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#911749 - 01/07/12 04:38 PM can i install an adjustable prop valve  
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can i install one of these before my stock metering block or does it have to be after it ?i would like to put it right next to the mast cyl but i dont know if i can do that with the stock metering valve in place


86 ss 86 cl,330hp GM vortec cratemotor-700-r trans worked,ford 9.5 inch rear with 3-50s,custom 3 inch exhaust with flowmasters.
#911761 - 01/07/12 06:07 PM Re: can i install an adjustable prop valve [Re: markg]  
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.. Put it in place of the stock non-adjustable prop valve...

.. Do you understand why an adjustable proportioning valve is desirable?


'86 Monte LS (total'd Fall '2013), '87 GTA TransAm TPI350 TH700-R4, '85 Fiero 5-speed, '75 MG Midget Buick Alum.V8 BW 5-speed manual, '77 Pontiac Astre Formula wagon 5-speed posi, '78 F150 4WD 351"M ==> 400" C6, '79 Caddy Seville Olds EFI 350" TH400, 19' Slickcraft 425HP 351W MerCruiser I/O
#912147 - 01/09/12 05:10 PM Re: can i install an adjustable prop valve [Re: BuzzLOL]  
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Baer says to gut the stock prop valve so that it still acts as a prop vavle. Maybe search Baer adjustable proportioning valve installation on google.

#913593 - 01/18/12 01:30 AM Re: can i install an adjustable prop valve [Re: SickSpeedMonte]  
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sorry for the late reply.
i installed it right after the stock metering block.it seems to work well but i have it adjusted all the way out which they claim is a 57 % reduction.
i did a brake swap in the rear recently and the rears have been locking up on a hard hit.the old stock ones would never lock up.
i put 11 inch drums in the rear from a caprice up from the 9 inch stock ones.
the old ones never seemed to work well and i even posted here several times about how i thought they werent working properly.
as soon as i did the upgrade i noticed a big difference in stopping power but they would lock up on a hard hit.
i had gotten kinda used to it and learned to feather the pedal.
i was on the freeway last week and had to do a panic stop in a lot of traffic.i was going about 70 mph.the rears locked up immediately and within a second or 2 i was completely 180 deg around!
i was still going at least 60 and had no idea what i was going to hit that would stop me.
i really thought that this was it.
i eventually went off to the side (still backwards)and went up on the guardrail.this crunched the quarter a bit and took off half my exhaust and bumpercover but that was all.i was able to drive it away.i was very lucky


86 ss 86 cl,330hp GM vortec cratemotor-700-r trans worked,ford 9.5 inch rear with 3-50s,custom 3 inch exhaust with flowmasters.
#913664 - 01/18/12 08:19 AM Re: can i install an adjustable prop valve [Re: markg]  
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Originally Posted By: markg
i installed it right after the stock metering block.it seems to work well but i have it adjusted all the way out which they claim is a 57 % reduction.

What brand adjustable PV valve are you using?

If the stock proportional valve is still in place(not gutted) that is just dangerous.
Originally Posted By: StopTech
We’ll start here with three of the most basic rules regarding proportioning valve installation and selection.

1. If you have the deeply-rooted need to install your own adjustable proportioning valve, be advised that they should NEVER be installed if the factory unit is still in place. Proportioning valves in series with one another can do nasty, unpredictable things!

2. If you have the deeply-rooted need to install your own adjustable proportioning valve, be advised that they should NEVER be installed in-line to the front brakes. The effect would be to make your vehicle rear-biased before you could say “terminal oversteer.” Front brake line pressure should always be left alone – only the rear pressures should be considered for proportioning.

3. In all cases, the basic brake system balance needs to be close to optimized to start with. This is the only way that a proportioning valve can be effectively utilized. You should never assume that simply adding a proportioning valve will address all rear-bias conditions, as even the best proportioning valves must be well-matched to the target vehicle.

From Brake Proportioning Valves The True Story
If one modifies a brake system, it needs to be modified as a system. You cannot cobble a system together by mix and matching parts without doing some basic calculations. What you will create is a death trap.
Originally Posted By: markg
i put 11 inch drums in the rear from a caprice up from the 9 inch stock ones.

Only B-body Wagons and 9C1 Sedans used the larger 15/16" wheel cylinders/11" rear drums, in conjunction with larger 70mm calipers/12" front rotors.
B-body sedans use 11" rotors/70mm calipers with 9" drums and 7/8" wheel cylinders.
G body uses 10.5" rotors/60mm calipers with 9" drums and 3/4" wheel cylinders.

If you have done the B spindle/70mm caliper swap a better upgrade would have been to use 7/8" wheel cylinders('82 S-10 with manual brakes) on the factory rear G body drum system.
Originally Posted By: markg
the old ones never seemed to work well and i even posted here several times about how i thought they werent working properly.

Automakers tend to make vehicle brakes more front biased than ideal. This keeps the car stable under emergency braking. If the cars were designed with optimum brake bias the average vehicle operator would probably end up yawing the car into a partial spin during anything above moderate braking.
Originally Posted By: markg

as soon as i did the upgrade i noticed a big difference in stopping power but they would lock up on a hard hit.
i had gotten kinda used to it and learned to feather the pedal.

The problem with the upgrade you did is at slower speeds and light braking, the car will feel better at stopping. However this is not completely true. To properly adjust the rear brake bias via the prop valve...
Originally Posted By: Maximum Motorsports
The rear brakes should never lock before the front. To be sure this doesn’t happen, start with the valve fully toward the “decrease” setting. Test hard braking in a safe and controlled environment. A race track is reccomended. Adjust the proportioning valve toward “increase”, until the rear brakes begin to lock at the same time as the front. At this point, turn the valve toward “decrease” until the rear tire lockup just goes away, and only the front tires lock up. This setting will give you greatly improved braking power and directional stability compared to the OEM proportioning valve.

From Install Instructions BPV-1

The above is only applicable if the system is correctly biased via rotor/drum diameter and caliper/wheel cylinder piston sizing.
Originally Posted By: markg

i was on the freeway last week and had to do a panic stop in a lot of traffic.i was going about 70 mph.the rears locked up immediately and within a second or 2 i was completely 180 deg around!

Originally Posted By: StopTech

We also know from fundamental brake design that the following factors will affect how much brake torque is developed at each corner of the vehicle, and how much of that torque is transferred to the tire contact patch and reacted against the ground:

· Rotor effective diameter
· Caliper piston diameter
· Lining friction coefficients
· Tire traction coefficient properties

From Why Brake Balance Matters
Rotor can be replaced with drum and caliper with wheel pistons. However, drums are a bit trickier to calculate due to different mechanical drum designs, where the wheel cylinder is located, and that whole self energizing effect. Although the GM Bendix drums have changed little since self energizing came to be.

From your experience at speed you know that the rears are capable of locking up. What you now need to do is get the bias forward.

What is your brake system now? If it's stock front brakes with the B-wagon rear drums this is not going to work no matter how much you adjust the PV.


-Michael
Where the hell is JMD?!
#913888 - 01/19/12 05:05 PM Re: can i install an adjustable prop valve [Re: MADMIKE]  
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nj
thank you so much!
what would you suggest i do in the front and still be able to run 15 inch wheels?
here is another prob i did not mention.my car is extremely high in the rear.the front is also very high.on a hard brake the front dives down and the rear lifts up.im thinking this is unloading a lot of weight off of the rear which makes it easier to lock up.i dont want to lower it because this is the look and stance i like.perhaps a set of shocks in the front with a higher "down" rate or maybe some type of bumpstops which prevent it from diving as much.
any help is greatly appreciated.
thanks
mark


86 ss 86 cl,330hp GM vortec cratemotor-700-r trans worked,ford 9.5 inch rear with 3-50s,custom 3 inch exhaust with flowmasters.
#913995 - 01/20/12 02:49 AM Re: can i install an adjustable prop valve [Re: markg]  
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First let me state that I made a slight error in the above B body combinations'

B-Sedan 11" Rotors/70mm Calipers and 9" Drums with 7/8" Wheel Cylinders.
B-Sedan 12" Rotors/70mm Calipers and 11" Drums with 15/16" Wheel Cylinders.(9C1)
B-Wagon 12" Rotors/70mm Calipers and 11" Drums with 1" wheel cylinders.

Originally Posted By: markg
what would you suggest i do in the front and still be able to run 15 inch wheels?

You can run 11" or 12" rotors with 15" wheels. That's what GM did with the 80s B bodies. I thought http://flynbye.com had brackets to use a 11" or 12" B rotor on a G spindle, but I could be mistaken. There is also the B-body spindle swap where you can utilize the 12" rotors.
Originally Posted By: markg

im thinking this is unloading a lot of weight off of the rear which makes it easier to lock up.

Weight transfer happens in all vehicles be it accelerating/decelerating or change of direction. Being your car is raised more than stock there is more weight transfer and it would be easier to unload the rear. Combined with your 11" rear brakes the rears lockup much easier now.

The problem currently with your car is there is too much rear brake bias. Your car simply does not need this much rear brake. You need to down grade from the 11" rear drums to the 9" drums and the smaller 3/4" wheel cylinder.

Since you have already changed to the 4 bolt style of rear brake mount you can just down grade to the 4 bolt backing plate for the 9" drum. You will need to use a 3/4" wheel cylinder from a '92 S-10 as well. If you still have your original G body 9" brakes, you can reuse all of the parts except the backing plate and wheel cylinder.

It would be better to change the front brakes to increase stopping power. Depending on what you decide to do this may also require a change in rear wheel cylinder size if there is a change in front caliper piston area.

e.g. if you do the B spindle swap with 70mm calipers you will need to change the rear wheel cylinder in size as well to keep the bias correct.


-Michael
Where the hell is JMD?!
#914234 - 01/21/12 02:44 AM Re: can i install an adjustable prop valve [Re: MADMIKE]  
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-Michael
Where the hell is JMD?!

Maybe at Barrett-Jackson.
Bob

#914709 - 01/23/12 05:46 PM Re: can i install an adjustable prop valve [Re: mmc427ss]  
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Great info MADMIKE!!

#914842 - 01/24/12 09:43 AM Re: can i install an adjustable prop valve [Re: mmc427ss]  
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Originally Posted By: mmc427ss
Maybe at Barrett-Jackson.
Bob

I haven't heard from Matt in years. Last time I had contact with him was before the monte-list went down back in '07(?). If you have a known good e-mail or contact info would you PM it to me? I would greatly appreciate it, thanks.


-Michael
Where the hell is JMD?!
#914978 - 01/25/12 05:11 AM Re: can i install an adjustable prop valve [Re: MADMIKE]  
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PM sent.
Bob

#915004 - 01/25/12 02:11 PM Re: can i install an adjustable prop valve [Re: mmc427ss]  
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mad mike.. nice write up.. but..
(and I'm sure this is a typo) is it 82 s-10 with manual brake or 92 like inyour last post..
also a few things that where left out.. on the b body drums and the wheel cyl size.. the body is a heavier car and has more rear weight bais..
the b body brakes are also designed with the likelyhood of the car towing something and having rear passangers more offen than not..
the b body brakes drum set up is tomuch rear brake for the g body even if you add the b body front brakes..
these cars just don't need that much brake in the rear.. the swept area might help in a solocross event.. MIGHT..
the problem with having that extra swept area and the testing listed in your post,is, the threshold of the drums locking up changes with use, a cold drum will tend to lock up faster than a hot ones ,say in a solocross course.. or a road race..
and I'm assuming(bad idea I know) that the bigger brakes where added because of spirted driving or racing.. so, the rear bais that you set in testing ,might not be the best set up when used on a road course.. to get those 11" drums to work(not lock up) you are almost shutting off the rear brakes.. even with the b body front brakes, 9 times out of 10 you don't need the bigger rear.. intill the hardcore autocross racing, and they don't add bigger drums, they go straight to disc.
Another thing that was not touched on. is the o/p set up.. all he said was his caris high in front and rear, and sounded like the rear is higher than the front.. a rake front to rearlooks kool, but does nothing for braking/traction or handling. I'dwork onfixing that before I even did anything else as changes here will change the rear brake bias.. brake dive.. without moving front sub. mounting points, you can slow it down with shocks..
I'd have started with the stock rear drums with good shoes and an in spec drum(not oversized, worn out)and added the adjustable bias control.. fixed the brake dive with shocks and maybe better springs(not knowing what the o/p has in the car)
huge brakes on the rear of cars are 99.9% of the time added for looks,, most could never use the stopping power of the pizza sized discs because of tires,springs,shocks,oem sub. mounting points.. and the public streets prep..
good braking is more than just the braking system.. fix/limit the brake dive and you'll be alot happier..
a new or barely worn 9" drum will out stop any 11" drum tat is worn.. as the drums warem the surface area of the shoe that hits the drum is smaller and the shoe has to "ware into the drum" something that in normal use takes thousands of miles.. I sand the shoes intill I get 80% of the shoe area touching the drum.. this kills service life,, but adds serface area contact, and less fade as more of the shoe is doing the work.
doing this yeilds better braking most times over justadding bigger drums.. cause why did you add the bigger drum, you added them for more surface area.. pop the drums off and spray bodywork guide coat (this is a carbon, not a paint.so you can't use a normal spraybomb.. ) spray the carbon based guide coat on the shoes, put it together and go for a drive.. come back and open the rear brakes and you'll see just how little of the shoe is touching the drums,, thats your working surface area.. sanding the shoes you can get more of the shoes touching the drum, as the area that touched is the high spots. ofcourse if your drums are oversized, worn. this is pointless..
the moreof the shoe that touches the better the braking will be.. you'll get less of a change from brake fade and a more predictable set up..


Oh when your body starts to shake,It's time to loosen off the brake ,and slam the hammer down
#915007 - 01/25/12 02:42 PM Re: can i install an adjustable prop valve [Re: Furgie]  
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The 11" rotor has more surface area and also has 22% more "leverage" or torque on the axle as a result of the larger diameter. Same concept as using larger diameter rotors with the same calipers/pads (in addition the added thermal capacity and surface area to dissipate heat and avoid fade). Plus the wheel cylinder has more leverage on the longer brake shoe (the distance b/w where the cyl contacts the shoe and the pivot point at the bottom increases) The mechanical gain factor probably remains pretty constant, maybe going up a hair.

I agree that I don't think I would be comfortable with 11" drums on the rear. If you are going to be road racing/auto crossing, the disc brakes give you much more linear control over the rear brake force, which better matches the front brake force.

#915023 - 01/25/12 04:24 PM Re: can i install an adjustable prop valve [Re: SickSpeedMonte]  
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this is cast iron.. the smaller drum cools faster.. wink
the 9" drums are more than enough.. the only down side of drums is the lag because the shoes back off. and have to move father than a disc brake pad does..
cars with heavy wheel/tire packages might need the extra "leverage" 17,18"rims are not light.. and short sidewalls don't seem to = lighter tires. for the same width/height..
your torque on the axle.. explain please.. no matter the leverage, you need traction on the road.. no traction.. you lock up the wheel.. , your torque on the axle, has me confused.. with a locked up converter, the engine does more to slow(brake) the driveline than the brakes are.. and is why I have a toggle switch to bypass the brake convrter clutch release at the brake pedal.. smile
when spirted driving..

Last edited by Furgie; 01/25/12 04:27 PM.

Oh when your body starts to shake,It's time to loosen off the brake ,and slam the hammer down
#915058 - 01/25/12 09:25 PM Re: can i install an adjustable prop valve [Re: Furgie]  
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There's a lot being discussed here, I'm going to break this up.

Originally Posted By: Furgie
this is cast iron.. the smaller drum cools faster.. wink


How do you figure that? The mode of cooling for the drum is going to be forced convection, and that is a function of the heat transfer coefficient (same for the 9" and 11" drums), as well as the difference in temperature of the drum and the air flow, and the surface area. A larger drum can hold more heat, but it will also have more surface area to dissipate it. The ratio of surface area to mass will be greater for the 11" drum, unless it gets proportionally thicker as well, which I doubt. Changing the material from cast iron to cast aluminum will change the heat transfer coefficient, but the same relationship holds true so I don't understand the reference to the material. If a smaller drum cools faster than a larger one, it is only because it got hotter in the first place with it's reduced thermal capacity.

Originally Posted By: Furgie
the 9" drums are more than enough..


Agreed, strictly in terms of the maximum braking power being enough to lock the wheels.

Originally Posted By: Furgie
the only down side of drums is the lag because the shoes back off. and have to move father than a disc brake pad does..


That's not true. The major disadvantage of a drum brake to a disc brake is the controllabiliity. As you apply a drum brake, the leading shoe (actually the rear shoe in our cars) wedges into the rotating drum, giving you the mechanical advantage. This is good for reducing the pedal effort, but it means that the braking force changes with time. From Fundamentals of Vehicle Dynamics, Gillespie, pg 52. "On drum brakes, the torque will often exhibit a "sag" in the intermediate portion of the stop. It has been hypothesized that this effect is the combination of temperature fade and velocity effects." The sag he is referring to is the shape of a graph that was the result of a brake dynamometer test, where the brake torque reduced in the middle of a stop due to increasing temperatures, and then climbed at the end due to the reduced velocity of the wheel. These causes are hypothesized, but the effects are measured and very real.

The other disadvantage of drums is brake force versus pedal apply force. With a disc brake, the equation is very simple. Brake force = pad friction coefficient * apply force. (Alright, it's slightly more complicated than that due to adhesion, in addition to hysteresis, but it's a good approximation and serves well for this discussion.) In other words, the brake force is direclty proportional to the apply firce. With a drum brake, it's much more complicated and much more sensetive to the coefficient of friction. In fact, if mew goes up too much, you can acutally lock the braks... that means you totally release the apply force and they will not unlock. Gillespie goes on to say that it is very difficult to proportion disc brakes and drum brakes to work well under all conditions because they do not react the same to pedal force inputs.

Originally Posted By: Furgie
cars with heavy wheel/tire packages might need the extra "leverage" 17,18"rims are not light.. and short sidewalls don't seem to = lighter tires. for the same width/height..
your torque on the axle.. explain please..


Torque on the axle generated by the brakes. It's not a torque that causes rotation like we are used to thinking of, but rather one that opposes the already existing rotation (road speed). A larger drum means that the interface between the shoe and the drum (where the brake force is generated) is further from the center of the rotating wheel/tire/axle. Because it is further out, the same brake apply force generates a greater "negative" torque on the axle, and therefore a greater decelerative force at the tire contact patch for the same diameter tire.

Originally Posted By: Furgie
no matter the leverage, you need traction on the road.. no traction.. you lock up the wheel.. , your torque on the axle, has me confused..


Now we are getting outside of the point I was trying to make. Of course traction is required to decelerate the car, but it doesn't have anything to do with the brake sensitivity or maximum braking force that I mentioned. In my first post, I was just trying to show that even though 11"/9"=1.222, going from a 9" drum to an 11" drum does not mean a 22% increase in braking force. If you only account for the swept area, you are not getting the whole picture.

Originally Posted By: Furgie
with a locked up converter, the engine does more to slow(brake) the driveline than the brakes are.. and is why I have a toggle switch to bypass the brake convrter clutch release at the brake pedal.. smile
when spirted driving..


So you are saying that if we both had the same car and you locked the convertor and closed the throttle, and I put it in neutral and braked at the threshold of tire traction or maximum brake power, whichever comes first, you would stop first? The brakes slow the driveline too, just from the other end of it... but what I said had nothing to do with this point. Don't get too caught up on the "axle" reference when I mentioned "axle torque". I only mentioned it because the axle is an easy to visualize center of rotation. Not becuase it has anything to do with the rest of the driveline. Maybe I should have just said center of wheel rotation.

#915060 - 01/25/12 09:41 PM Re: can i install an adjustable prop valve [Re: SickSpeedMonte]  
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Originally Posted By: SickSpeedMonte
Plus the wheel cylinder has more leverage on the longer brake shoe (the distance b/w where the cyl contacts the shoe and the pivot point at the bottom increases) The mechanical gain factor probably remains pretty constant, maybe going up a hair.


Turns out this isn't true. I ran some hypothetical numbers and the effect of increasing all drum dimensions (not including the wheel cylinder) doesn't change the brake apply force (in terms of hysteresis)

The greater surface contact area might give higher braking force from the adhesion component.

The other point about the shoe/drum interface being further from the axle centerline still holds true.

#915068 - 01/25/12 10:22 PM Re: can i install an adjustable prop valve [Re: SickSpeedMonte]  
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So you are saying that if we both had the same car and you locked the convertor and closed the throttle, and I put it in neutral and braked at the threshold of tire traction or maximum brake power, whichever comes first, you would stop first? The brakes slow the driveline too, just from the other end of it... but what I said had nothing to do with this point. Don't get too caught up on the "axle" reference when I mentioned "axle torque". I only mentioned it because the axle is an easy to visualize center of rotation. Not becuase it has anything to do with the rest of the driveline. Maybe I should have just said center of wheel rotation.


my set up, thebrakes don't have to slow the driveline, onlythe car.. so mybrakes will stop faster all things being equal, because mine isn't try'n to stop the axle, the gears, the driveshaft the trannys internals, an converter/orflywheel spinning.... as the engines braking will slow all of that allowing the brakes to only have to stop the movement of the car.. no matter if you have gibbs racing abs

Last edited by Furgie; 01/25/12 10:24 PM.

Oh when your body starts to shake,It's time to loosen off the brake ,and slam the hammer down
#915087 - 01/25/12 11:49 PM Re: can i install an adjustable prop valve [Re: Furgie]  
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Originally Posted By: Furgie
is it 82 s-10 with manual brake or 92 like inyour last post..

Originally Posted By: MADMIKE
If you have done the B spindle/70mm caliper swap a better upgrade would have been to use 7/8" wheel cylinders('82 S-10 with manual brakes) on the factory rear G body drum system.

Originally Posted By: MADMIKE
Since you have already changed to the 4 bolt style of rear brake mount you can just down grade to the 4 bolt backing plate for the 9" drum. You will need to use a 3/4" wheel cylinder from a '92 S-10 as well. If you still have your original G body 9" brakes, you can reuse all of the parts except the backing plate and wheel cylinder.

Originally Posted By: Furgie
the b body brakes drum set up is tomuch rear brake for the g body

Originally Posted By: MADMIKE
If it's stock front brakes with the B-wagon rear drums this is not going to work no matter how much you adjust the PV.

Originally Posted By: MADMIKE
The problem currently with your car is there is too much rear brake bias. Your car simply does not need this much rear brake. You need to down grade from the 11" rear drums to the 9" drums and the smaller 3/4" wheel cylinder.

Originally Posted By: Furgie
a cold drum will tend to lock up faster than a hot ones

This is dependent if there is condensation on the brake shoe material. Organics are better when cold/light braking vs semi-metallic or ceramics, but drop off in stopping ability when heat is induced.
Originally Posted By: Furgie
Another thing that was not touched on. is the o/p set up...you can slow it down with shocks..

Shocks should only be used to correctly dampen the springs. The suspension should be looked at for correcting unwanted lift and dive characteristics. Too stiff of a shock absorber on a spring will prevent the spring from allowing the tire to maintain contact with the road. The car will skip about and the ride will be horrible.
Originally Posted By: Furgie

I sand the shoes intill I get 80% of the shoe area touching the drum..

Sandpaper has aluminum oxide in it, this can embed into the shoe material and transfer to the drum.
Modifying the shoe is similar to the old practice of re-arching the shoe to fit a worn drum. I don't think anyone does it anymore.
A simplie alternative would be to locate shoes with more aggressive stopping compounds. Dealing with asbestos laden shoes or soft organic compounds are a thing of the past.


-Michael
Where the hell is JMD?!
#915092 - 01/26/12 12:20 AM Re: can i install an adjustable prop valve [Re: MADMIKE]  
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well, my last set of brakes, done in 2004 (before the car was parked) stopped the car in 126 feet from 60mph, with the poor 10.5" front rotors and sad 9" drums..
better adjustable shocks, and stock everything else..
on eagle gtII 215/65/15"
we did 8 back to back 60-0 test.. the last one was 129 feet.. not bad for outdated, to small brake set up..

Last edited by Furgie; 01/26/12 12:21 AM.

Oh when your body starts to shake,It's time to loosen off the brake ,and slam the hammer down
#915093 - 01/26/12 12:23 AM Re: can i install an adjustable prop valve [Re: Furgie]  
Joined: Dec 2011
Posts: 131
Furgie Offline
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Furgie  Offline
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Posts: 131
Rustbeltville,MA
btw a new 2002 ws6 t/a was only 6 feet shorter stoping times..


Oh when your body starts to shake,It's time to loosen off the brake ,and slam the hammer down
#915099 - 01/26/12 01:07 AM Re: can i install an adjustable prop valve [Re: Furgie]  
Joined: Jul 2003
Posts: 9,209
SickSpeedMonte Offline
15+ Year
SickSpeedMonte  Offline
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Member

Joined: Jul 2003
Posts: 9,209
MD
Only if your rear brakes cant put the rear tires at the limit of traction without engine braking helping.

#915101 - 01/26/12 01:13 AM Re: can i install an adjustable prop valve [Re: Furgie]  
Joined: Jul 2003
Posts: 9,209
SickSpeedMonte Offline
15+ Year
SickSpeedMonte  Offline
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Member

Joined: Jul 2003
Posts: 9,209
MD
Curious how you conducted your brake testing

#915113 - 01/26/12 02:23 AM Re: can i install an adjustable prop valve [Re: SickSpeedMonte]  
Joined: Dec 2011
Posts: 131
Furgie Offline
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Furgie  Offline
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Joined: Dec 2011
Posts: 131
Rustbeltville,MA
I didn't test it.. a replacement brake company, tested the car with a third wheel..
back to back test of 4 different vendors..
all on the same day.. all at watkins glen.
all I did was install and drive .. they ran the test..
you can get the same pads at advanced..

or wagner

Last edited by Furgie; 01/26/12 02:25 AM.

Oh when your body starts to shake,It's time to loosen off the brake ,and slam the hammer down
#915251 - 01/27/12 01:33 AM Re: can i install an adjustable prop valve [Re: Furgie]  
Joined: Jun 2001
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markg Offline
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markg  Offline
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nj
wow!
thanks for all of the info!
with the manual prop valve now in place the rear will lock if i really stand on it.i think if someone else who wasnt aware of what was going on could still lock the rear in a panic stop.
also it rained the other nite and on a wet road it will lock up much easier.i dont remember trying this with the stock rear brakes.
do u think i should bother trying the larger wheel cylinders in the rear or should i just go back to the 9 inch brakes?
my friend who builds rear axles and told me this was an upgrade said that this was the same exact setup as on a 73ish elcamino with 11 inch rear drums.this year car would also have the same front brakes as ours(im told)
the elcamino seems like it would be lite in the rear for this setup.
i would love to keep the 11 inchers because i dont have any of the old stuff anymore but if this current setup is not going to work i would rather ditch it now.


86 ss 86 cl,330hp GM vortec cratemotor-700-r trans worked,ford 9.5 inch rear with 3-50s,custom 3 inch exhaust with flowmasters.
#915331 - 01/27/12 11:09 AM Re: can i install an adjustable prop valve [Re: markg]  
Joined: Jul 2010
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MADMIKE Offline
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MADMIKE  Offline
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Posts: 81
C.V. CA
Originally Posted By: markg

with the manual prop valve now in place the rear will lock if i really stand on it.i think if someone else who wasnt aware of what was going on could still lock the rear in a panic stop.

Ideally, you should never be able to lock the rear tires, especially in a panic stop. All that nose diving and tire smoking theatrics may look good on TV but it's not practical or safe.
Originally Posted By: markg
do u think i should bother trying the larger wheel cylinders in the rear or should i just go back to the 9 inch brakes?

Go back to the 9" drums.
Originally Posted By: markg

my friend who builds rear axles and told me this was an upgrade said that this was the same exact setup as on a 73ish elcamino with 11 inch rear drums.this year car would also have the same front brakes as ours(im told)

'73-'77 A bodies had 11" rotors and 75mm calipers.
'78-'88 A/Gs have 10.5" rotors and 63.5mm calipers.
The suspension geometry is also different. Both are GM RWD intermediates but they are different generations and different designs.
Originally Posted By: markg

the elcamino seems like it would be lite in the rear for this setup.

It is also a truck. The brake system is designed with the forethought that a load will be in the bed.
The 11" brakes were an option on the '73-'77 El Camino. They also used the 9" drums. Theh lasat generation of El Camino had a slighlty longer wheel base than the rest of the G body line. Was this true for the previous generation? If so keep in mind...
Originally Posted By: StopTech
· Weight distribution of the vehicle at rest
· CG height – the higher it is, the more weight gets transferred during a stop
· Wheelbase – the shorter it is, the more weight gets transferred during a stop


-Michael
Where the hell is JMD?!
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