MonteCarloSS.com

Manual Brake Conversion on a 1980 El Camino

Posted By: malibudave78

Manual Brake Conversion on a 1980 El Camino - 01/02/12 10:08 PM

I just finished up upgrading the brakes on my father’s 1980 El Camino. This is a daily driver that I am testing several different master cylinders for a manual brake conversion swap. His brakes worked good before exchanging out all the parts, but I wanted to take out most of the variables when testing master cylinders. First and foremost, I wanted to make sure this 1980 El Camino did not have quick take up front brake calipers. In my research, quick take up calipers will make it difficult do get good pressure to the caliper when using manual brakes.

Here is the rundown of the parts I used:
• Speedway Motors Big Bore Metric Calipers - PN# 91031040 $59.99 each
• Bendix Titanium metallic front brake pads (FF Rated) - PN# MKD154 $38.22
• Turned the stock rotors $30 Local Auto Parts Store $15 each
• Edelbrock/Russel Stainless Steel Braided Flex Lines PN# 692100 $54.80
• Wagner 7/8” Wheel Cylinders from an manual brake S10 PN# F110261 $13 each
• Wagner Thermo Quiet Rear Shoes (EE Rated) - PAB514R from O’Reilly’s Auto $32.99

The Speedway Motors big bore metric calipers (2.75” bore v 2.38” bore standard) came with brake pads, but the pads did not have a rating on them. I DID NOT want to use a brake pad that would need a lot of heat to be effective. The weight difference between the two calipers is less than ½ of a pound. This is a daily driver and not an autocross car, so I chose the Bendix Titanium pads because my research and reviews showed them to have good cold clamping friction. Based on the EE rating, the rear shoes should also have good cold stopping abilities. Look on the pads or shoes when you buy them to make sure they have a rating on them. The higher up the alphabet you go the hotter the pads will have to be to work effectively. Pads or shoes with no rating on them should be avoided.

It was surprising to me to find a 24mm strait bore aluminum master cylinder on this 1980 El Camino. I didn’t know they made aluminum ones with a strait bore for g-bodies. I had always been under the impression, because it was aluminum, that this was a step bore master for quick take up calipers. I do know for a fact that any NEW replacement master cylinders for g-bodies will for than likely be cast iron. So if you want aluminum master cylinder for power or manual brakes that bolt up to your brake lines, a rebuilt master cylinder may be your only option.

I changed out the 30 year old rubber brake lines with the braided stainless. The front lines were a little longer than the originals, but I routed them so they were not touching any suspension pieces. The rear was a little more difficult to replace because the clip that holds the rubber line to the frame was difficult to get at. The new braided rear line was fairly easy to install also.

The hardest part to the entire swap was installing the rear wheel cylinders. Getting the clip off was not too bad, but getting the clip back on was a pain. I did it with two c-clamp, and open ended wrench, and the lid off of an old battery terminal cleaner (don’t ask for these details because I do not recommend doing it this way. G-H-E-T-T-O).

After the system install, bleeding the fluids, and bedding in the pads and shoes I took it out for a spin to test the brakes with the same master cylinder and vacuum booster from the original test with the original brakes. Even though I was able to easily lock up all four wheels, it seems to have a little more pedal travel before you could feel the brakes start to grab. I believe this has to do with the increased piston area in the front calipers and rear wheel cylinders while using the strait bore 24mm master cylinder. The 24mm master cylinder will have more pedal travel to fill the extra volume of fluid required by the calipers and wheel cylinders.

If keeping the vacuum booster, it might be best to step up to the step bore master cylinders that are used on the 1981 and up g-bodies. The primary bore is still 24mm, but it also has a larger step bore of 36mm that will increase the volume of fluid to the larger calipers and wheel cylinders.
Posted By: malibudave78

Re: Manual Brake Conversion on a 1980 El Camino - 01/02/12 10:09 PM

The manual brake conversion went well. I kept the stock , 31 year old, 24mm master cylinder that came with the stock power boosted brake system. I kept the 24mm master, for now, because I upsized the front calipers and wheels cylinders. It stopped the car ok, but I felt I still had too much pedal travel and I couldn't get the front brakes to lock up. I am going to rebleed the calipers, unbolted from the spindle, to point the bleeder screws up at the 12 o'clock position. If this doesn't do the trick, I will bolt on a brand new manual brake master cylinder from a 1978 to 1980ish g-body. This master cylinder has a smaller bore which should give me higher pressure at the pad.

Before manual brake conversion:




After manual brake conversion:


Posted By: malibudave78

Re: Manual Brake Conversion on a 1980 El Camino - 01/02/12 10:09 PM

I rebled the front calipers unbolted from the spindle to try and get rid of some of the spongyness in the pedal. I did this to see if there was any more air in the system at the caliper by rotating the bleeder screw at the 12 o'clock position and bleeding the system. No air at the caliper, so I think the origanal 31 year old master cylinder has air in it or it is bad.

I am going to replace it with a new 7/8" bore master cylinder from a manual brake 1978 g-body ($60 from amazon). Though it is made of cast iron, it is the smallest bore master cylinder that readily bolts on. I know of no aluminum master cylinders that are 7/8" bore that will readily bolt on, other than one of the expensive aftermarket ones. I would also like to test a master cylinder from a Dodge Dakota. It has a 24mm bore, is aluminum, and with one brake fitting adapter, it bolts into place with the adapter plate I am using.
Posted By: malibudave78

Re: Manual Brake Conversion on a 1980 El Camino - 01/02/12 10:11 PM

Here is the pushrod assembly I put together that is in my dad's El Camino.

It is adjustable from roughly 3.75 inches to about 4.25 inches.

Blown apart


Assembled Top View


Assembled Side View
Posted By: GuysMonteSS

Re: Manual Brake Conversion on a 1980 El Camino - 01/03/12 04:01 AM

So how well do the brakes work now Dave ??? Unless I'm missing something,this looks like a fairly easy modification,and cheap too.I have previously upgraded my front brakes very similar to what you have done,although I used the USBrakes oversize metric calipers,Hawk HPS pads,slotted & crossdrilled rotors and Russell braided SS hoses,and the Ford 9 inch has rear drums much bigger than stock.The brakes work much better than stock but the vacuum runs out after a couple of pumps.I bought an electric vacuum pump,but I am reluctant to clutter up the engine compartment with it,and yours sure looks pretty clean without the booster.So tell us a bit more on how your dads brakes work,and how big a job it was too change over to manual.
Guy
Posted By: malibudave78

Re: Manual Brake Conversion on a 1980 El Camino - 01/03/12 11:00 AM

Originally Posted By: GuysMonteSS
So how well do the brakes work now Dave ??? Unless I'm missing something,this looks like a fairly easy modification,and cheap too.I have previously upgraded my front brakes very similar to what you have done,although I used the USBrakes oversize metric calipers,Hawk HPS pads,slotted & crossdrilled rotors and Russell braided SS hoses,and the Ford 9 inch has rear drums much bigger than stock.The brakes work much better than stock but the vacuum runs out after a couple of pumps.I bought an electric vacuum pump,but I am reluctant to clutter up the engine compartment with it,and yours sure looks pretty clean without the booster.So tell us a bit more on how your dads brakes work,and how big a job it was too change over to manual.
Guy


The car stops OK with the 32 year old 24mm bore master cylinder it has on it now, but I cannot get the brakes to lock up. There is some sponginess in the pedal that I suspect is either a bad 32 year old master cylinder or I have air in the rear brake lines somewhere. I am waiting for my brand new 1978 Malibu 7/8" bore manual brake master cylinder in the mail to change over from the 24mm bore strait bore.

Hardest part of the install is bolting it to the firewall. You will need a someone else to help align everything up and bolt it down to the firewall. The pin (stud) will also need to be pressed into the brake pedal using a press. If using a plate without a retention cup, it bolts directly to the firewall with no modifications to the firewall. With a plate with the retention cup, the firewall will have to be trimmed a little to clear the retention cup.

It is really not a hard job to install a manual brake system. The hardest part is getting it to work correctly.

There are usually 3 main reasons why manual brake setups on g-body cars, s-10 trucks, and 3rd generation Camaros/Firebirds do not function well.

1. Low drag calipers
2. The small piston diameter in the low drag caliper
3. The master cylinder

You and I have numbers 1 and 2 covered above which takes out most of the variables. I am working on number 3 by testing out master cylinders and narrowing down which ones work best with my setup.
Posted By: GuysMonteSS

Re: Manual Brake Conversion on a 1980 El Camino - 01/03/12 01:00 PM

Very interesting Dave,please be sure to keep us updated as you go,and take lots of pictures.So what,if any,is the advantage,or dis-advantage,to using the retention cup ??
Guy
Posted By: malibudave78

Re: Manual Brake Conversion on a 1980 El Camino - 01/03/12 05:16 PM

I will keep you updated. I am waiting for a 1978 Malibu manual brake master cylinder with a 7/8" bore to install and test.

Because the manual brake master cylinder from a g-body has a shallow cup to retain the pushrod (actually it is just a dimple), the pushrod is not held in by anything. You need a retention cup (or something other devise) to make sure it doesn't fall out the back of the master cylinder. If the pushrod does come away from the master cylinder piston, the retention cup keeps it in line with the "dimple".

Pushrod Fall Out the Back = No Brakes = Injury or Death
Posted By: howehot

Re: Manual Brake Conversion on a 1980 El Camino - 01/03/12 08:22 PM

On the Schwatrz chassis I'm getting it will have manual brakes with 13" wilwood brakes 6 piston front 4 piston rear. Jeff told me to he uses a master cylinder for a 70 corvette for this application. Cheap and works great. My be your answer.
Posted By: malibudave78

Re: Manual Brake Conversion on a 1980 El Camino - 01/03/12 10:17 PM

Originally Posted By: howehot
On the Schwatrz chassis I'm getting it will have manual brakes with 13" wilwood brakes 6 piston front 4 piston rear. Jeff told me to he uses a master cylinder for a 70 corvette for this application. Cheap and works great. My be your answer.


13" wilwood brakes with 6 piston fixed front calipers and 4 piston fixed rear calipers is a lot larger caliper piston area than a big bore 2.75" metric caliper front and 7/8" wheel cylinders in the rear. Schwartz says to use a 1970 Corvette manual master cylinder with a 1” bore. That bore size is comparatively small compared to the brakes it supports. I am not saying their wrong. It just proves a point that you do not need a big master cylinder to have good manual brakes. Your master cylinder needs to be sized proportionately to the brakes you are using.
Posted By: ProTourAero

Re: Manual Brake Conversion on a 1980 El Camino - 01/04/12 01:44 AM

I have the same Wilwood brake set up on mine 13" - 6 Piston on front, 4 piston on rear, and I use the Wilwood 1Ό" master.
It's not manual, I have a hydroboost, but it works real well.
Posted By: pazzo1969

Re: Manual Brake Conversion on a 1980 El Camino - 01/04/12 02:08 AM

Good, i feel confident the twin piston front and rears from strange will hold up with the Strange master cylinder with 1.25 bore and 1.550 stroke part #b3359. Mike
good thread here nice info
Posted By: malibudave78

Re: Manual Brake Conversion on a 1980 El Camino - 01/04/12 02:20 PM

I ordered a Raybestos MC39166 7/8" bore master cylinder from Amazon for about $75, but it was taking 1 to 2 months for delivery, so I cancelled the order. I then went out to rockauto.com and order a Dorman unit M39166 for less than $45 with shipping.
quote]

Well the Dorman master cylinder from rockauto.com was also out of stock. Customer representative called me up to explain that there was a mistake in the system. He talked me into a Wagner unit MC101252. Roughly $65 with shipping. Hopefully it wil be here by the weekend so I can test this master, weather permitting.
Posted By: GuysMonteSS

Re: Manual Brake Conversion on a 1980 El Camino - 01/04/12 03:56 PM

Dave,I hope you get that master cylinder,I am really looking forward to how well it works out for you.
Guy
Posted By: malibudave78

Re: Manual Brake Conversion on a 1980 El Camino - 01/05/12 12:31 AM

A day after I talk with the rockauto.com representative, I recieve my Wagner 7/8" bore 1978 Chevrolet Malibu manual brake master cylinder in the mail.

See something wrong with this picture? Reservior is on backwards. I will turn it around before i bench bleed it.



Made in the Good Ol' U. S. of A.



7/8" bore master cylinder piston with the pushrod "dimple"



I pushed in the piston with a brake pedal pushrod I had laying around. Travel was a little over an inch.

Weight of 7/8" Manual Brake Master Cylinder
3 lbs 5 1/8 ounce

Weight of Aluminum Step Bore S-10 Master (24mm / 1 1/4" step bore)
2 lbs 8 1/4 ounce

Only a little over a 3/4 of a pound difference.

I need to grind down some of the casting flash and shoot is with some aluminum or black colored paint to keep it looking fresh and not like a peice of rust after about a year.
Posted By: malibudave78

Re: Manual Brake Conversion on a 1980 El Camino - 01/05/12 02:03 AM

Just an FYI.

The manual brake setup talked about in this thread uses the stock g-body manual brake configuration. The manual brake pin (stud), pictured in the pushrod linkage above, is pressed into a pre-drilled hole that is already in the stock vacuum power boosted pedal from the factory. There is no drilling involved with this setup.
Posted By: syclonesuper

Re: Manual Brake Conversion on a 1980 El Camino - 01/05/12 04:24 AM

That,s the master I used also works great
Posted By: malibudave78

Re: Manual Brake Conversion on a 1980 El Camino - 01/05/12 10:15 AM

Originally Posted By: syclonesuper
That,s the master I used also works great


What is your brake setup (rotors, calipers, drums, wheel cylinder, etc.)?
Posted By: malibudave78

Re: Manual Brake Conversion on a 1980 El Camino - 01/08/12 02:47 PM

Weight differences between Mater Cylinders.

Weight of Cast Iron 7/8" Manual Brake Master Cylinder
3 lbs 5 1/8 ounce

Weight of Aluminum Step Bore S-10 Master (24mm / 1 1/4" step bore)
2 lbs 8 1/4 ounce - difference of 12 7/8 ounces or a little over 3/4 lbs over the cast iron unit

Weight of an Aluminum Mopar / Strange style master cylinder
2 lbs 2 3/4 ounce - difference of 1 lb 2 3/8 ounces over the cast iron unit
Posted By: malibudave78

Re: Manual Brake Conversion on a 1980 El Camino - 01/08/12 02:48 PM

Worked on the new 7/8" bore manual brake master cylinder for a 1978 malibu, Wagner part number MC101252.

I ground off the front casting "imperfections"



I ground off the bottom casting "imperfections"



I painted it with some aluminum color paint I had from a previous project.

Posted By: GuysMonteSS

Re: Manual Brake Conversion on a 1980 El Camino - 01/08/12 11:43 PM

Looking good Dave !!!
Guy
Posted By: malibudave78

Re: Manual Brake Conversion on a 1980 El Camino - 01/09/12 12:41 AM

UPDATE:

I had trouble getting the brakes bled. I bench bled the system, but for some reason I couldn't get any pedal after I installed the system. I am going to use a bleeder kit to push brake fluid up to the master cylinder from the wheel cylinders and calipers. I will not be able to get to it until January 21st or 22nd, so stay tuned in until then.

Let me know if you have any questions.
Posted By: GuysMonteSS

Re: Manual Brake Conversion on a 1980 El Camino - 01/18/12 12:42 AM

Hey Dave,are you making any progress with your install ???
Guy
Posted By: malibudave78

Re: Manual Brake Conversion on a 1980 El Camino - 01/18/12 04:39 AM

Originally Posted By: GuysMonteSS
Hey Dave,are you making any progress with your install ???
Guy


Haven't had the time to finish it up. I am looking at this weekend to get it completed. All I have to do is get the master cylinder bled and rebleed all the lines to make sure no air is in the system.
Posted By: GuysMonteSS

Re: Manual Brake Conversion on a 1980 El Camino - 02/02/12 06:27 PM

Hey Dave,just wondering how you are coming along with this project,keep us updated...
Guy
Posted By: MAP

Re: Manual Brake Conversion on a 1980 El Camino - 02/02/12 11:37 PM

Hi Folks,

MC bore area is a double-edged sword. As area goes down, pressure goes up for a given pedal force, and so other things being equal, a higher braking deceleration ought to be attainable. But if there are any compliances in the system such as caliper flexure, piston seals, flex cables, pad "wedgeness," or, of course, air in the brake fluid, then the pedal will feel spongier as MC bore area goes down, which subjectively creates the impression that the brakes aren't as "responsive" or as "firm." In other words, the pedal response is opposite to the braking response. The exact same effect is seen if the pedal leverage ratio increases: the braking force goes up, but so does the impression of sponginess in light of any system compliances.

Best,
MAP
Posted By: malibudave78

Re: Manual Brake Conversion on a 1980 El Camino - 02/03/12 10:25 PM

MAP,

I would have to agree with what you said about compliances in the braking system. Floating calipers are not as "efficient" as fixed calipers, rubber lines are not as "efficient" as braided stainless, flex in the calipers because they are not ridgid, low drag piston seals, etc. All that is very understandable.

All g-body cars with stock brakes have all of these. Floating, small, single piston, low drag caliper, with rubber lines and a small front rotor.

I would think that the #1 contributor to spongy brakes is air in the lines, and it is the most obvious. The other less obvious, for g-body cars, is the low drag caliper used in conjunction with a strait bore master cylinder and maybe rubber flex lines.

Besides the 3 above factors, how much more sponginess would you get from a floating caliper than a fixed? How does the "wedgeness" work and how do you maximize the effectiveness of the pad? How ridgid is a stock metric g-body front caliper?

I know the best solution would be to drop a couple of grand on an aftermarket multiple piston, fixed aluminum caliper with a large rotor and an aftermarket master cylinder. How do you maximize a stock front brake system for manual brakes for our cars other than aftermarket metric calipers, braided stainless flex lines, and a good street brake pad, with a good working master cylinder?
Posted By: malibudave78

Re: Manual Brake Conversion on a 1980 El Camino - 02/03/12 10:38 PM

Originally Posted By: GuysMonteSS
Hey Dave,just wondering how you are coming along with this project,keep us updated...
Guy


Time. I need more of it. I am actually considering having a mobile mechanic come out and bleed the entire system and be done with the bleeding and actually having some time to see how well the manual brake system works with all the new parts.

Dave
Posted By: MAP

Re: Manual Brake Conversion on a 1980 El Camino - 02/03/12 10:49 PM

Hi Malibu,

Brakes are not my forte: in this area, I speak more from theory than from practice. But I'll try my best:

1. Air in brake fluid biggest contributor to sponginess: probably yes, but there's also a vanishingly small density of air in the liquid where it will no longer be the dominant compliance.

2. Low-drag caliper: clearly to go from low drag to high drag (i.e., applied brakes,) will require an increase of force and some displacement of fluid. The real question is partial F/ partial V.

3. How much sponginess for a floating vs. fixed caliper? I haven't the foggiest idea. It comes back to the definition in (2.).

4. "Wedgeness": The pads don't wear exactly parallel to the rotor surface since the distribution of clamping force (and thus pad wear,) isn't uniform across the pad, but higher on the pad's leading edge. Some of the partial F/partial V involves displacing some additional fluid to restore the pad face to a parallel alignment with the rotor surface.

5. How rigid is a stock metric g-body front caliper (or any other caliper for that matter): I haven't the foggiest. Probably 1e9 N/m if not greater!

6. "How do you maximize..." I don't know, which is the reason why I only offer restricted comments on the topic.

Best,
MAP

Posted By: malibudave78

Re: Manual Brake Conversion on a 1980 El Camino - 02/14/12 01:29 PM

I want to let everyone know that there has been one issue with the calipers that I recommended from Speedway Motors. Its the Speedway Motors Big Bore Metric Calipers - PN# 91031040 $59.99 for each.

Here are the links that describe the issue.

http://www.maliburacing.com/forum/viewtopic.php?f=2&t=111382

http://www.gbodyforum.com/viewtopic.php?f=14&t=35367&sid=fe32adcefeafad16021984241fd71525

I have not had any problems with the ones I have bought. I have been told that these calipers are made by U.S. Brake when I first bought mine from Speedway Motors.

There are other options for big bore calipers, but they are a little more expensive from Wilwood.

http://www.speedwaymotors.com/Wilwood-GM-Iron-Metric-Calipers,24192.html
Posted By: GuysMonteSS

Re: Manual Brake Conversion on a 1980 El Camino - 02/14/12 03:53 PM

Very interesting stuff Dave,although I havent had any issues with the ones that I got from USBrake,and they have been on my Monte for a couple of years now.So how are you coming along with your project ??? I am still considering the manual brake swap,but not until I see how it works out for you.
Guy
Posted By: malibudave78

Re: Manual Brake Conversion on a 1980 El Camino - 02/14/12 04:08 PM

It looks as if I will be finishing up the bleeding of the brakes this Friday afternoon.

Hopefully, I don't run into any issues and I will let you know how it goes.
Posted By: MAP

Re: Manual Brake Conversion on a 1980 El Camino - 02/15/12 12:13 AM

Hi 78,

To hear of even one instance of such a failure is enough for me not to buy from them. The low cost is another tip-off that quality control might not be everything it needs to be.

May I recommend that before driving the car, you start the motor and literally stand on the brake pedal to make sure nothing goes "pop?"

Best,
MAP
Posted By: MAP

Re: Manual Brake Conversion on a 1980 El Camino - 02/16/12 08:38 PM

Hi 78,

In addition to the matter of mechanical stress at room temperature, is the added stress created by the enormous temperature range the caliper sees in service. I'd buy top quality for brakes because one's life literally depends on it.

Best,
MAP
Posted By: GuysMonteSS

Re: Manual Brake Conversion on a 1980 El Camino - 02/17/12 02:18 PM

Mark,this makes me wonder if the USBrake big bore calipers vs the Speedway ones,which are quite similar,may have different manufacturing locations.There is quite a big difference in pricing,app 30-40 dollars per caliper,maybe quality accounts for this difference ???.The USBrake ones I have appear to be high quality,at least from a visual inspection.And no breakage so far.
Guy
Posted By: MAP

Re: Manual Brake Conversion on a 1980 El Camino - 02/17/12 04:16 PM

Hi Guys,

I have no idea about manufacturing source. And, even for a bad vendor, 999,999 out of 1,000,000 may be good, but if you're driving the car with that millionth caliper, well - it could be a bad hair day.

With my employer, I know the tolerance for a failure leading to a fatality, is targeted for 1e-9 failure rate or less, that is - one in a billion or less.

I know that the hotrodding world tends to wing it a lot more than the corporate world, because the corporations are the ones with the big lawyers who file the big law suites, and who in turn get sued big-time. Even so, I don't like to roll the dice with my life.

Best,
MAP
Posted By: malibudave78

Re: Manual Brake Conversion on a 1980 El Camino - 07/29/12 09:26 PM

Purchased an additional new 7/8" bore master cylinder just in case the older new one I bought doesn't work like it is suppose to when I install it on the El Camino. When I was bench bleeding the older, new one, the front port for the rear brakes would suck the fluid back into the master cylinder after the piston was released. The rear port for the front brakes didn't have this issue.

Is this normal? I don't know, but I will find out from the new master cylinder that I bought.

I also baught a rebuilt, aluminum master cylinder, with a 1" bore, from a 1979 Buick Riviera with the optional rear disc brakes. I did this because the reservior is larger, it can be retro fitted to the 7/8" bore manual brake master cylinder, and it matched the angle of the firewall. You don't need it for rear drum brakes, but I like the extra fluid capacity.
Posted By: malibudave78

Re: Manual Brake Conversion on a 1980 El Camino - 07/29/12 09:27 PM

Here is a link to a person that carries new Proportioning Valves for Ford, GM, and Jeep.

http://proportionvalves.com/

Here is a link to a disc/drum PV for a g-body from the http://proportionvalves.com/ site.

http://www.carolinaclassictrucks.com/78-86-malibu-PV2.html

Here is a link to a disc/disc PV for a 2nd gen f-body that looks like it will work with g-body brake lines if you convert to rear disc brakes. Please call to confirm it will bolt in.

http://www.carolinaclassictrucks.com/79-81-TransAM-PV4.html

MOPAR MASTER CYLINDER RETROFIT
I may have found a way to retrofit a 7/8” mopar (1993 Dodge Shadow) master to a g-body for manual brakes. I have not tested this yet to see if this works.

For the Front Brake port on the Proportion Valve:
Edelmann 258350 - Adapter-Standard To Dual Master Cylinder - 3/16" Tube - 3/8-24 Female Inverted Flare Seat x 1/2-20 Male Inverted Flare

For the Rear Brake Port on the Proportion Valve:
Edelmann 258340 - Adapter-Standard To Dual Master Cylinder - 3/16" Tube - 3/8-24 Female Inverted Flare Seat x 7/16-24 Male Inverted Flare

I don’t know the length of the brake lines from the proportion valve to the mopar master, but flared lines are less than $10 each from the auto parts stores. It should be about 2 to 3 foot of line. A coat hanger can be used to find the actual length needed.

If this setup works, this will be the cheapest way to get an aluminum master cylinder retrofitted to a g-body.

Let me know if you see any issues with what has been posted above.
Posted By: malibudave78

Re: Manual Brake Conversion on a 1980 El Camino - 07/29/12 09:28 PM

A Wilwood master cylinder will not work with the angle of a g-body firewall if the Wilwood master cylinder is bolted directly to the firewall. It physically bolts up, but there is a hole at the bottom of the master cylinder that regulates the fluid from one reservior to the other. When bolted directly to the firewall, the angle will let all the fluid run to the back reservior and the front reservior is left almost empty.

The Wilwood master should work on a TRZ or TNT adapter plates because these adapter plates correct the angle of the firewall and allows the master cylinder to sit horizontal (level) to the ground.
Posted By: malibudave78

Re: Manual Brake Conversion on a 1980 El Camino - 07/29/12 09:28 PM

I have purchased 3 different metric calipers for comparison:

**CCP big bore 2.75" bore (2.565" piston diameter) metric cast iron caliper – WEIGHT 6 lbs 11.2 oz bare with slider bushings installed
**US Brake standard bore 2.5" bore (2.376" piston diamter) metric cast iron caliper- WEIGHT 6 lbs 4.7 oz bare with slider busings installed
**Wilwood small bore 2.0" bore (1.981" piston diameter) metric cast iron caliper - WEIGHT 4 lbs 1.7 oz bare with NO SLIDER BUSHINGS INSTALLED.

A while back I purchased NEW the $59.95 each, big bore calipers from speedwaymotors.com. There was some manufacturing issues or problems with these calipers and they sent me replacement calipers. The replacement calipers are NEW CCP big bore metric calipers. PN CP412526. Online, these are the same price of $59.95 each from classicperform.com. They look exactly the same except for the paint on the calipers. The originals where painted/powder coated silver. These are painted/powder coated black. The caliper housing, compared the standard bore US Brake 2.5” calipers and 2.0" Wilwood calipers, are a different casting. The piston looks to be stainless steel and comes with a dust boot installed. The piston diameter is 2.565" in diameter. These calipers came loaded with pads, slider bolts/pins, and hose fittings. You should be able to bolt these to your car, bleed the brakes, and drive. The piston cylinder side of the caliper is roughly the same size as the as the standard 2.5” bore caliper.

I recently purchased NEW, US Brake/Afco branded 2.5” standard bore metric calipers. They are $45 to $50 each online. The casting is not painted or powder coated. They come in a right PN 7241-9003 and a left caliper PN 7241-9004. They cannot be interchanged from side to side. The piston looks to be a cast steel/iron, unlike the CCP 2.75” and Wilwood 2.0” bore calipers. They are also 2.376" in diameter which matches stock advertised piston/bore sizes. The casting looks to be a stock casting and comes with a dust boot installed. It has all the markings of a stock calipers. This caliper came unloaded with no pads, slider bolts/pins, and hose fittings. It does come with the bleeder screws and bushing inserts for the slider bolts/pins. You will have to reuse your slider pins from your stock calipers and hose fittings. You will need to purchase new pads or reuse the ones you have on your car.

I also recently purchased NEW, Wilwood 2.0” small bore metric calipers. PN 120-9333. The price is round $80 each online. It is also a different casting from the other two. Visually the casting looks better and it looks to come with a stainless steel piston that is 1.981" in diameter. The casting comes bare with no paint or powder coating and they can be interchanged from the right and left hand side of the car. The piston cylinder portion of the caliper is physically smaller than the other two because of the reduced size of the piston. The piston bore and stainless steel piston look to have a better, tighter fit. The clearance is so tight there is no dust boot installed around the piston like the 2.75” and 2.5” bore caliper above. These calipers only come with a bleeder screw. It does not come with any other hardware. You will have to supply the slider bolts/pins, slider bolt/pin bushing inserts (I need to make sure this is possible), brake pads, and hydraulic hose fittings. All hardware should be able to transfer over from your original caliper. Please refer to this web page for more details. http://www.wilwood.com/PDF/Flyers/fl176.pdf

Out of the three calipers above, I was most impressed with the Wilwood calipers. These calipers have a very clean casting that weigh at least 2 lbs less than the other two calipers. The Wilwood website list a 2.75” bore version also that weighs just 5 more ounces than the Wilwood 2.0” bore versions (4lb 6.4oz v 4lb 1.6oz). These Wilwood iron calipers weigh roughly 1lb more than the Willwood comparable aluminum metric caliper with the 2.38” bore (4lb 6.4oz v 4lb 1.6oz v 3lb 6.4oz). I also suspect that the piston to bore clearances are just as tight as their 2.0" verson which will give the 2.75" version of the Wilwood caliper a larger piston that that of the CCP version. It theory this gives more clamping force.
Posted By: malibudave78

Re: Manual Brake Conversion on a 1980 El Camino - 07/29/12 09:29 PM

Pics of the CCP 2.75" Big Bore Metric Caliper





Posted By: malibudave78

Re: Manual Brake Conversion on a 1980 El Camino - 07/29/12 09:30 PM

Pics of US Brakes / AFCO 2.5" Driver's Side Metric Caliper





Posted By: malibudave78

Re: Manual Brake Conversion on a 1980 El Camino - 07/29/12 09:30 PM

Pics of Wilwood 2.0" Bore Metric Caliper





Posted By: malibudave78

Re: Manual Brake Conversion on a 1980 El Camino - 07/29/12 09:31 PM

I purchased my second new master cylinder from rockauto.com a while back and just now had time to install it. The master cylinder is a Centric brand PN# 130.62005. It is a manual brake master cylinder for a g-body with a 7/8" bore. I installed it and bleed the brakes from back to front and got a good, firm pedal. I left the speedway motors recalled calipers installed, for now, to see how the system all worked together. I noticed, while I was under the car bleeding the brakes, I saw a lot of caliper defection as my dad pumped the brake pedal when the bleeder screws where closed.

How did it do? For the setup I have, it did very well. I could not lock up the front brakes, but the braking felt more confident than when I had the stock, 24mm bore power master cylinder . I felt, if I was driving this on the street a lot, I wouldn't have to anticipate my braking. I felt I could stop where I wanted to when I wanted to under normal street driving. As expected, the pedal stroke is longer than a power brake pedal.

What would I do different? I would find a better front caliper. I think I will try the Wilwood single piston, 2.75" bore, metric caliper. From my experience with the inspection of 2" bore, Wilwood, single piston, metric calipers, I think the 2.75" big bore Wilwood will have a larger piston that the CCP/Speedway Motors 2.75" big bore caliper. I just worry that any 7/8" bore master cylinder may not have the volume of brake fluid needed to make these work.
Posted By: malibudave78

Re: Manual Brake Conversion on a 1980 El Camino - 07/29/12 09:32 PM

Things I learned from this process.

*New master cylinders are hit or miss in functionality. My first new one I bought did not work, but it was a clearance item from rockauto.com. I ended up spending another $80 plus shipping for the Centric brand one that actually worked.
*The larger the caliper piston is the better the clamping force.
*Caliper deflection affects brake performance more that I thought.
*The smaller the bore of the master cylinder is the better the pressure to the caliper.
*But if the bore of the master cylinder is to small, it may not have enough fluid to fully compress the caliper piston.
*The diameter of the brake rotor also affects the performace of the brakes not only because of rotor area and heat dissipaton, but also a larger diameter rotor gives the brakes greater leverage. Just think of using a 6" long breaker bar instead of a 5.25" braker bar to get a bolt loose. A longer bar will have a easier time getting the bolt loose. A 10.5" rotor has a 5.25" (half the rotor diameter) of "leverage". A 12" rotor has 6" of "leverage". Larger is better.
*They make brake pad designed for drag racers. They work better when cold and are for vehicles that do not use their brakes on a daily basis.
*Wilwood makes nice metric calipers.
Posted By: malibudave78

Re: Manual Brake Conversion on a 1980 El Camino - 08/08/12 04:01 AM

Just recieved my Wilwood 2.75" big bore calipers in today. These are very nice calipers, just like the Wilwood 2 inch metric calipers. The piston diameter measures 2.704 inches. On the underside of the caliper, there are ridges that bridge the piston side (inside) of the caliper to the wheel side (outside) of the caliper. These ridges are not present on any of the other calipers. These ridges should cut down of caliper deflection. The weight of each of the 2.75" calipers is 4 lbs 8.6 ounces with out the bleeder screw. I hope the 7/8" bore g-body manual brake master cylinder can handle the increase in volume these calipers may require.





Posted By: malibudave78

Re: Manual Brake Conversion on a 1980 El Camino - 08/08/12 04:01 AM

Caliper Specs

Caliper............................Part Number........Advertised Bore Size.......Actual Piston Size.....Weight
Wilwood 2" Bore Caliper........PN 120-9333...................2.00"..........................1.981"................4lb 1.6oz
US Brake / AFCO Caliper.......PN 7241-9004..................2.50"..........................2.376"................6lb 4.7oz
CCP Big Bore Caliper............PN CP412526...................2.75"...........................2.565"................6lb 11.2oz
Wilwood 2.75" Bore Caliper....PN 120-8926...................2.75"...........................2.704"................4lb 8.6oz
Posted By: malibudave78

Re: Manual Brake Conversion on a 1980 El Camino - 08/27/12 04:24 PM

This week I put on the Wilwood big bore calipers. I got them bled and immediately had less pedal pressure when using the 7/8” G-Body manual brake master cylinder. The pedal almost went to the floor. I assume it is from the increased piston diameter over the Speedwaymotors.com “Big Bore” calipers (2.704” Wilwood v 2.565” Speedwaymotors/CCP) that I replaced. When driving with the Wilwood big bore calipers, I could pump the pedal 3 or 4 times and get the pressure I needed and would lock up the right rear tire and stop the car just like the other calipers. I suspect now I will need a 24mm bore G-body master cylinder (from a power, vacuum boosted G-body) and EE rated front pads to replace the FF rated front pads I have on the front now. The EE rated front pads have better “bite” when the rotor is colder. FF rated front pads have better “bite” when the rotor heats up. Since this is a street driven car, the EE rated pads should be a better choice and will match the rear EE rated shoes that are already on the car.
Posted By: malibudave78

Re: Manual Brake Conversion on a 1980 El Camino - 11/21/12 11:21 PM

I am done testing the manual brake setup with a stock, aluminum, rebuilt, 24mm bore, 1980 El Camino master cylinder. With only this change, I got back the brake fluid pressure that I lost when I upgraded to the Wilwood 2.75” metric calipers using the 7/8” bore master cylinder. I bench bleed the master cylinder installed it in place of the 7/8” bore master cylinder, bled the line at the master cylinder, and then bled the car at all four wheels.

On the test drive, using the 24mm master, I did a few hard stops from about 30 mph. I was rewarded with both rear wheels locking up, but the front braking system felt as if it still wasn’t grabbing. After the testing, I jacked the front of the car and removed the wheels and I unbolted the calipers so I can take a look at the pads. I suppose during my very first manual brake test, I did not bed the brakes in properly and I glazed the brake pads over. I do not know why I did not notice this when I put on the Wilwood calipers other than not recognizing what glazed pads look like. The glazing most likely happened because I had a large master cylinder and small calipers on my first manual brake test and, at the time, I wasn’t getting enough pressure to the pads to do accomplish correct bedding. The moral of the story is to bed your pads properly.

Good news is that I found out what the issue is with the front brakes not grabbing. Bad news is that I didn’t deglaze my pads and retest. I didn’t deglaze the pads I originally used because went ahead and upgraded to a Wilwood Polymatrix A brake pad.

I went to the Wilwood PolymatrixA pad because of its good, cold clamping properties and, before I realized about the glazing pads, I had thought this would help with front brakes. **As a warning from Wilwood to any one using these pads, Wilwood considers these race pads**. These are aggressive pads and will most likely wear the front rotors prematurely and are intended for race use only. These pads have almost twice the friction coefficient as a “stock” type pad. I am using this aggressive pad because the front rotors are small, the brake pads are small, the front calipers are a floating design, and the car is now has manual brakes. These pads are also a wallet buster at $150 a set.

The braking test with these pads where a noticeable night a day difference. I felt very comfortable and confident while driving and stopping. On hard stops, the nose of the car would “dive” down and the rear wheels still locked up. Only time will tell if these front pads are good for everyday use with this manual brake setup.

If your car is a daily driver and not a drag car, you most likely do not need to change out to larger wheel cylinders on the rear drum brakes like I did. The original stock 3/4” bore wheel cylinders versus the larger 7/8” bore wheel cylinders should reduce rear lock up on hard braking.

For a drag racer with large, wide, sticky tires on the back, the larger 7/8” bore wheel cylinder may be better to keep the rear tires from spinning when your holding the car on the line with just the brakes. An aggressive front pad may also be needed to hold the car on the line (contact one of the major brake pad manufactures for suggestions).

From my experience, to do a manual brake system on a g-body or s-10, some or all of the brake components will have to be replaced. You cannot just remove the vacuum booster and bolt the master cylinder to the firewall and expect your braking to function well. It is a system approach.

Do you need an oversized caliper? In my opinion, no you do not.

Do you need to change out the front calipers? In my opinion, yes you do. Why? Because the stock calipers may or may not be a LOW DRAG design which requires a step bore master cylinder. How do you know that you have LOW DRAG calipers? You actually cannot physically tell, so its best to buy aftermarket calipers to cut down on variables that may cause trouble with your braking system.

Do I recommend rebuilt front calipers from the auto parts store? No. See above.

Do you need to change out the master cylinder? In my opinion, most likely you will need to. Why? It depends on what you are starting with. If you have a GM g-body vehicle that was built from 1978 to 1980, you have a strait bore, 24mm bore master cylinder from the factory and you can just upgrade to Wilwood 2.75” bore calipers if you master cylinder is in good working order. If you have a vehicle built from 1981 through 2003 you most likely have a step bore master cylinder. These master cylinders are too large for almost all manual brake conversions on a g-body or s-10. Now a choice has to be made. How much money do you want to spend on aftermarket front calipers? Cheapest ones that I have found are around $45 each with a stock size bore from U.S. Brakes. You will then need a 7/8” bore master cylinder to match to these front calipers. For a g-body car you can go with a new or rebuilt, stock replacement from a 1978 to 1980 g-body manual brake master cylinder. For an S-10, the only option I have found that readily bolts to the firewall and to the brake lines is a Wilwood 7/8” bore master cylinder. If upgrading to the Wilwood 2.75” bore calipers, you will need a 24mm master cylinder. The g-body options are a new or built stock power brake unit from a 1978 to 1980 g-body car. New ones will be cast iron. Most rebuilt ones will be cast iron. For some reason, the 1980 model years came in aluminum and these can be bought rebuilt (like I have installed in the latest test). For a s-10, you can use a stock replacement manual brake master cylinder from a 1982 to 1992 s-10 truck with manual brakes. These are step bore master cylinders with a primary bore of 1-1/4” and a secondary bore of 24mm. I do not recommend these master cylinders because they are hard to bleed and have a bypass valve that can fail. The other options are a 24mm Wilwood master cylinder and a 1990s 24mm Dodge Dakota master cylinder. Only issue with the Dakota master is the rear brake port is 9/16-20 instead of 9/16-18. I have found no adapter for this conversion yet.

Do I recommend step bore master cylinders? No, because they are generally too large for a stock size front caliper, they are hard to bleed, and they have a bypass valve that may fail. These three issues can be remedied by using a correct size strait bore master cylinder. A 7/8” bore master cylinder for stock bore, aftermarket calipers and 24mm bore master cylinder for a Wilwood 2.75” bore calipers.

Do I recommend other oversized front calipers other than the Wilwood 2.75” front calipers? No, because their piston size in these oversized calipers are not much larger than stock. The Wilwood caliper, visually, looks to be engineered better.

Do I recommend stock size calipers? U.S. Brake is the only caliper, of the aftermarket cast iron replacements I know, that is not a low drag caliper. There may be other aftermarket, “metric” calipers, but I cannot confirm if they are low drag or not. The U.S. Brake calipers are based on a stock casting. The other alternative is a stock, replacement aluminum, “metric” caliper from Wilwood. I have not used or viewed one of these calipers, but from engineering of the 2.75” bore and 2.00” bore calipers I have viewed, I suspect they should be just as well engineered and lighter.

Do I recommend larger wheel cylinders? If the car is street driven, most likely no. If drag raced, most likely yes to keep the rear tires from spinning when doing a brake stand

Do I recommend braided stainless steel flex lines? Yes, for the reduced ballooning and better pedal feel, but is not necessary.
Posted By: malibudave78

Re: Manual Brake Conversion on a 1980 El Camino - 06/22/13 03:11 AM

Here is a list of strait bore master cylinders that will bolt up to a G-body’s angled firewall when using a flat, manual brake adapter plate. This is a list from smallest to largest.

21mm (0.826”) bore 1993 Dodge Shadow master cylinder (other years and models may work)
• Requires adapters to mate master cylinder outlet to stock lines. The adapter Part number is MC-SF at http://www.classicperform.com.
• Mounting holes spaced 3.25” versus GM master cylinder’s 3.375”.
• Hard to find.
• Light in weight.
• Advertised as 21mm, but may be delivered in 7/8” or 24mm bores. Measure bore size before you buy. Rebuilt/Used ones will have a “1” cast into the front of the aluminium body under the reservoir.
• Can buy new or used. New ones are fairly cheap to purchase.
• Aluminium body – new, used, or rebuilt.
• Large reservoir can hold enough fluid for rear disc brakes.

7/8” (0.875”) bore 1978-1980 GM G-body manual brake master cylinders.
• Can buy new or used. Rebuilt are fairly cheap. New are fairly expensive.
• Reservoir too small for rear disc brakes. The reservoir from 1979 Buick Riviera with four wheel disc brakes can be retrofitted to this master cylinder.
• Advertised as manual brake units, but may be delivered as a 24mm, vacuum power boosted unit. Measure bore size before you buy.
• Bolt in.
• Cast iron body – new, used, or rebuilt. (no aluminium)

7/8” (0.875”) bore 1993 Dodge Shadow master cylinder (other years and models may work)
• Requires adapters to mate master cylinder outlet to stock lines. The adapter Part number is MC-SF at http://www.classicperform.com.
• Mounting holes spaced 3.25” versus GM master cylinder’s 3.375”.
• Easier to find.
• Light in weight.
• Advertised as 7/8”, but may be delivered in a 24mm bore. Measure bore size before you buy.
• Rebuilt/Used ones will have an “8” cast into the front of the aluminium body under the reservoir.
• Can buy new or used. New ones are fairly cheap to purchase.
• Aluminium body – new, used, or rebuilt.
• Large reservoir can hold enough fluid for rear disc brakes.

24mm (0.944”) bore 1978-1980 GM G-body power brake master cylinders.
• Can buy new or used. Used are fairly cheap. New are fairly expensive.
• Reservoir too small for rear disc brakes. The reservoir from 1979 Buick Riviera with four wheel disc brakes can be retrofitted to this master cylinder.
• Bolt in.
• Come in cast iron and aluminium. 1978-1979 are cast iron. 1980 is aluminium (some models i.e. El Camino).
• New master cylinders will most likely be cast iron regardless of year.
• Rebuilt units come in cast iron and aluminium (1980 – some models).

24mm (0.944”) bore 1993 Dodge Shadow master cylinder (other years and models may work)
• Requires adapters to mate master cylinder outlet to stock lines. The adapter Part number is MC-SF at http://www.classicperform.com.
• Mounting holes spaced 3.25” versus GM master cylinder’s 3.375”.
• Easiest to find.
• Light in weight.
• Advertised as 24mm, but may be delivered in a 7/8” bore. Measure bore size before you buy.
• Rebuilt/Used ones will have a “4” cast into the front of the aluminium body under the reservoir.
• Can buy new or used. New ones are fairly cheap to purchase.
• Aluminium body – new, used, or rebuilt.
• Large reservoir can hold enough fluid for rear disc brakes.

24mm (0.944”) bore 1993 Dodge Dakota master cylinder (other years and models may work)
• Rear brake line outlet is 9/16-20 versus GM rear brake line fitting of 9/16-18. The fitting for GM brake line may be used to “rethread” the master cylinder’s outlet.
• Front brake lines bolt up.
• Mounting holes spaced 3.25” versus GM master cylinder’s 3.375”.
• Can buy new or used. New ones are fairly cheap to purchase.
• Aluminium body – new, used, or rebuilt.
• Large reservoir can hold enough fluid for rear disc brakes.
• Reservoir not angled like above Dodge and GM master cylinders.

1.0” bore 1979 Buick Riviera with 4 Wheel Disc Brakes.
• Can buy new or used. Used are fairly cheap. New are fairly expensive.
• Reservoir is made for rear disc brakes.
• Bolt in.
• Come in cast iron and aluminium.
• New master cylinders will most likely be cast iron.
• Rebuilt units usually come in aluminium.

1 1/32” (1.03”) bore 1985 Dodge Diplomat master cylinder (other years and models may work)
• Rear brake line outlet is 9/16-20 versus GM rear brake line fitting of 9/16-18. Fitting for GM brake line may be used to “rethread” the master cylinder’s outlet.
• Front brake lines bolt up.
• Mounting holes spaced 3.25” versus GM master cylinder’s 3.375”.
• Can buy new or used. New ones are fairly cheap to purchase.
• Aluminium body – new, used, or rebuilt.
• Large reservoir can hold enough fluid for rear disc brakes.
• Reservoir not angled like above Dodge and GM master cylinders.

1 1/8” (1.125”) bore 1985 Dodge Ram master cylinder (other years and models may work)• Rear brake line outlet is 9/16-20 versus GM rear brake line fitting of 9/16-18. Fitting for GM brake line may be used to “rethread” the master cylinder’s outlet.
• Front brake lines bolt up.
• Mounting holes spaced 3.25” versus GM master cylinder’s 3.375”.
• Can buy new or used. New ones are fairly cheap to purchase.
• Aluminium body – new, used, or rebuilt.
• Large reservoir can hold enough fluid for rear disc brakes.
• Reservoir not angled like above Dodge and GM master cylinders.
Posted By: malibudave78

Re: Manual Brake Conversion on a 1980 El Camino - 01/02/15 12:51 AM

One of the main problems that arise when converting to manual brakes using a 7/8" bore master cylinder is LOW drag calipers.

LOW drag calipers require a step bore (quick take up) master cylinder. In my opinion they are too large to operate smaller 2.50" bore calipers with sufficient pressure, they are harder to bleed, and they have a 100lb residual valve that can fail. My opinion also is to change out to new (NOT rebuilt) calipers to make sure you do not get a set of LOW drag calipers.

To learn a little bit about new stock size calipers, I just purchased a set of left and right AFCO 2.5" bore metric calipers that are a bolt in, stock, replacement caliper for g-bodies, S10s, and most 3rd gen f-bodies. I removed the stainless steel piston and square piston seal to make sure it was not a LOW drag caliper.

SPECS:
MFG. Part #: 7241-9003 RH and 7241-9004 LH
Centerline of Holes: 5.50
Caliper Pistons: Single Piston Diameter: 2.50
Inlet fitting: 10mm-1.5 Material Type:
Steel Finish: Natural
Sold in Quantity: Each

Description:
The 2 1/2" bore steel GM metric caliper is designed to be a used as a stock replacement caliper. The caliper features a stock appearing remanufactured castings, remanufactured grounded 2 1/2" stainless steel piston, and low drag seals (see below) . Each caliper is assembled and pressure tested.

LOW DRAG SEALS
Though the description says "low drag seals", the seals are square with no noticable taper.




The seal-groove in the bore of the caliper are also square with no noticable taper.


When the seal is installed, it barely clears the top of the bore, and because of this, the piston to bore clearance, it seams, to have fairly tight tolerances.

The small end of the piston is what contacts the back of the brake pad. It measures 2.38".
The large end of the piston is what is inside the bore of the caliper. It measures 2.50"


Inside of piston cup, facing the brake pad.


Backside of piston that is installed inside the caliper bore.


I have bought these same exact part numbers a few years back and these new ones are a different casting with, what looks to be, a stainless steel piston. These calipers DO NOT come with pads, but they come with slider pins and slider pin bushings. At this time, they are around $40, and seem to be an improvement over the previous design.

Bottom line is that these should be a good stock replacement, NON low drag, brake caliper that will work with both strait bore master cylinders and step bore (quick take up) master cylinders.
Posted By: malibudave78

Re: Manual Brake Conversion on a 1980 El Camino - 08/27/15 07:46 PM

Caliper Update:

I have found a good NON low drag (normal) bolt in replacement brake calipers for stock front brake systems. These brake calipers can be used with strait bore (normal) master cylinders and step bore master cylinders.

It is under the Centric Brand. They are about $33 plus shipping at rockauto.com.

Part number are:
14162066
14162065

AFCO has a brand new replacement brake calipers. They are about $49.99 plus shipping. $100 order are free shipping at Summit Racing, Jegs, and Speedway Motors. These should be NON low drag.

The part numbers are:
6635003
6635004
Posted By: malibudave78

Re: Manual Brake Conversion on a 1980 El Camino - 12/07/15 05:28 PM

Manual brake installation with adapter plate painted satin black to match firewall better.

Posted By: malibudave78

Re: Manual Brake Conversion on a 1980 El Camino - 02/18/16 04:56 PM

Below is an analysis using the Brake Torque Calculator found on Pro-Touring.com. This calculator will give you an idea of what brake torque is for a certain front and rear setups. I am just going to show the changes from the stock front g-body brake system and compare them to a Blazer dual piston brake swap, a stock LS1 Camaro brake swap, a LS1 Camaro brake swap with Corvette calipers

Page 7, Post #140

http://www.pro-touring.com/threads/10458...-of-KORE3/page7
This entire post is a really good read if you are interested about brakes.


Here are the inputs that are the same for ALL different types of brake systems shown below.
• 6 to 1 pedal ratio
• 26” tall tire
• 100 ft/lb pedal pressure
• Manual Brakes – NO POWER ASSIST
• Pad Coefficient of Friction - .45
• Use of stock type (tandem) master cylinder

____________________________________________________
Stock G-body/S10/3rd Generation F-body Front Brake System
• Rotor Diameter – 10.5”
• 7/8” Bore Master Cylinder Area - .601 sq-in
• Line Pressure – 998 psi
• Front Caliper Piston Area – 4.909 sq-in
• Front Clamping Pressure – 4899 pounds
• Front Rotor Torque – 964 ft/lb
• Tire Forces – 890 lb
____________________________________________________
Stock LS1 Camaro/Firebird Front Brake System
• Rotor Diameter – 12”
• 7/8” Bore Master Cylinder Area - .601 sq-in
• Line Pressure – 998 psi
• Front Caliper Piston Area – 4.931 sq-in
• Front Clamping Pressure – 4921 pounds
• Front Rotor Torque – 1107 ft/lb
• Tire Forces – 1022 lb
____________________________________________________
Stock LS1 Camaro/Firebird Front Brake System with Corvette Calipers with 7/8” bore master cylinder
• Rotor Diameter – 12”
• 7/8” Bore Master Cylinder Area - .601 sq-in
• Line Pressure – 998 psi
• Front Caliper Piston Area – 3.994 sq-in
• Front Clamping Pressure – 3986 pounds
• Front Rotor Torque – 897 ft/lb
• Tire Forces – 828 lb

Stock LS1 Camaro/Firebird Front Brake System with Corvette Calipers with 21mm bore master cylinder
• Rotor Diameter – 12”
• 21mm Bore Master Cylinder Area - .537 sq-in
• Line Pressure – 1117 psi
• Front Caliper Piston Area – 3.994 sq-in
• Front Clamping Pressure – 4461 pounds
• Front Rotor Torque – 1004 ft/lb
• Tire Forces – 927 lb

____________________________________________________
Stock Blazer Twin Piston Front Brake System
NOTE: The Blazer twin piston front calipers have a piston area too large to run a .875” bore master cylinder. These calculations are using a 24mm bore master cylinder.
• Rotor Diameter – 10.75”
• 24mm Bore Master Cylinder Area - .701 sq-in
• Line Pressure – 856 psi
• Front Caliper Piston Area – 5.152 sq-in
• Front Clamping Pressure – 4410 pounds
• Front Rotor Torque – 889 ft/lb
• Tire Forces – 821 lb

Stock Blazer Twin Piston Front Brake System
NOTE: The Blazer twin piston front calipers have a piston area too large to run a .875” bore master cylinder. But to show the differences between the systems, these calculations are using a .875” bore master cylinder.
• Rotor Diameter – 10.75”
• 7/8” Bore Master Cylinder Area - .601 sq-in
• Line Pressure – 998 psi
• Front Caliper Piston Area – 5.152 sq-in
• Front Clamping Pressure – 5142 pounds
• Front Rotor Torque – 1036 ft/lb
• Tire Forces – 956 lb


Rating from best to worst:
1. LS1 Camaro / Firebird stock front brakes with 7/8" bore master cylinder.
2. Blazer Twin piston stock front brakes with 7/8” bore master cylinder. NOTE: This setup will not work with a 7/8” bore master cylinder.
3. LS1 Camaro / Firebird front brakes with Corvette brake calipers and a 21mm bore master cylinder. NOTE: A 21mm master cylinders are fairly rare and hard to find.
4. Stock g-body/S10/3rd Generation F-body stock front brake system with 7/8" bore master cylinder.
5. LS1 Camaro / Firebird front brakes with Corvette brake calipers and a 7/8” bore master cylinder.
6. Blazer Twin piston stock front brakes with 24mm bore master cylinder.
Posted By: malibudave78

Re: Manual Brake Conversion on a 1980 El Camino - 01/24/17 10:13 PM

Since being around brakes a lot since I started manualbrakes.com, sometimes I get a reoccurring question when people are doing the conversion.

What ports do my lines bolt up to?

The ports on all G-body master cylinders have a ½-20 inverted flare port (port closest to the firewall) for the front brakes and a 9/16-18 inverted flare port (port located toward the front of the master cylinder) for the rear brakes. The manualbrakes.com KIT comes with adapters to mate the stock GM line fittings to the MOPAR style master cylinder’s 3/8-24 inverted flare outlets.

For most GM applicatiosn, remember:
Rear port of master cylinder goes to the front brakes.
Front port of master cylinder goes to the rear brakes
Posted By: malibudave78

Re: Manual Brake Conversion on a 1980 El Camino - 01/24/17 10:17 PM

Master Cylinder Bleeding Proceedures.

NOTE: DO NOT bench bleed a master cylinder on the car. On a g-body the master cylinder sits at an angle and it WILL NOT get all the air out of the master cylinder. Use a vise to hold the master cylinder level to the ground to bleed the master cylinder of all its air.

I like to use plugs to bleed the master cylinder of air instead of the procedure that uses hoses to recirculate the fluid from the master cylinder ports back up to the reservoir. Why?

When using plugs to close off the ports of the master cylinder, this procedure will let you know if all the air is out of the master cylinder AND if the master cylinder is bad. You don't want to find out your master cylinder is bad after you have it installed and are trying to bleed the rest of the system. You most likely will not get all the air out of the system when your master cylinder is bad. New or rebuilt, it is always good to make sure your master cylinder is in good working order before bolting it onto the car. It will one less thing you have to trouble shoot if you run into other issues when you are trying to trouble shoot braking issues.

Steps to bleeding a master cylinder:
1. Mount the master cylinder in a vise with the bore of the master cylinder level with the ground. Do not use the top of the reservoir as a guide because is may not be level with the bore of the master cylinder. It may be at an angle versus the bore of the master cylinder.
2. Use the appropriate size solid plugs to plug the outlets of the master cylinder so no fluid can escape the ports.
3. Fill the master cylinder with the appropriate amount of brake fluid.
4. Use a rod to SLOWLY cycle the master cylinder piston in its bore. DO NOT use a flat head or phillips heat screwdriver because they have sharp edges and could harm the bore of the master cylinder. I usually use a nut driver that is used for Ό” drive sockets as a rod because the end does not have any sharp edges and there is a handle to hold onto.
5. After cycling the master cylinder piston SLOWLY a few times, the piston should become rock solid and only move about 1/16 of an inch or less down the bore.
6. After the piston becomes rock solid, push in on the master cylinder piston and hold for 45 seconds. If the piston slowly moves down the bore of the master cylinder, you have a bad master cylinder. If the piston says rock solid and does not move, you master cylinder is good.
7. Mount to your car and bleed the rest of your system starting with the brakes furthest away (passenger rear) from the master cylinder and working your way to the closest (drivers front) brake.
Posted By: malibudave78

Re: Manual Brake Conversion on a 1980 El Camino - 03/12/17 02:06 PM

This is from The Brake Man at tbmbrakes.com from his Facebook page. It may make you think a little differently about aluminum calipers and multiple piston calipers.

12 RULES YOUR BRAKES LIVE BY:

1. Pad area (volume) has no effect on braking torque. Pad area (volume) effects life and heat management.
2. Caliper clamping force is a function of piston area (on one side of the rotor) times line pressure.
3. The hotter the brake pad gets, the faster it will wear.
4. Deflection anywhere in the brake system will result in a proportional reduction in clamping force.
5. Piston count has nothing to do with clamping force, piston area does.
6. Caliper deflection that exceeds piston O-ring retraction (around .020”) will result in brake drag.
7. Given the same design, aluminum calipers will always deflect more than steel, cast iron, or steel reinforced calipers.
8. If your pads are tapered, your calipers are deflecting.
9. All brake pads perform best in a temperature range. Too cold is just as bad as too hot.
10. The smallest, lightest rotor that will dissipate the necessary heat is the best rotor for the application.
11. A smaller bore master cylinder increases line pressure.
12. Larger diameter caliper piston(s) increase clamping force.
Posted By: malibudave78

Re: Manual Brake Conversion on a 1980 El Camino - 06/28/17 05:34 PM

I pulled this information from the CPP website. I include this information on this thread because, during a manual brake conversion, the differential valve in the proportioning/combination valve may be triggered and cause only one side of the system to work resulting in poor braking performance.

The differential valve is built into most GM prop valves. It is for safety. If one side, front or rear, of the brake system looses pressure, the differential valve is triggered blocking off the low pressure side of the brake system so that the master cylinder can still provide pressure to the other side of the brake system. This ensures that there is some for of braking as a way to stop the vehicle. If a differential valve was not part of the braking system, and there is a loss of pressure in one side of the system, the master cylinder would not be able to build pressure. This would result in NO brakes.

Combination/Proportioning Valve Test

Use a test light by attaching a clip to a positive contact on the vehicle and touch the point of the tester to the electrical connection of the combination valve. If the the light does NOT come on, the valve system is operating correctly and no further testing is required.

If the light does come on, this indicates that the pressure differential valve is stuck in the front or rear position.

Bleed the brake system to determine if the front or rear lines are blocked off. Set up one front wheel and one rear wheel for bleeding at the same time. Crack both bleeder screws and gently pump the pedal a few times.

The blocked side will trickle fluid out when the bleeder screw is cracked and the pedal pressed. An unblocked line will squirt fluid out the bleeder.
The lines that are clear must be left open and the blocked lines should have the bleeder screws tight to cause pressure to build up on that side. Be sure to use the standard bleeding procedures to prevent air from entering the system.

Slowly press the pedal with steady pressure a number of times until the light goes out; this will center the differential valve. You may also hear a pop come from the proportioning valve. This is the metering valve returning to its equalized position. When the light goes out, close the bleeder screw. (See fig. below)


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