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#1073877 - 05/10/22 12:04 AM Stock 86, High Speed Vibration  
Joined: Oct 2016
Posts: 110
guitars Offline
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guitars  Offline
Member

Joined: Oct 2016
Posts: 110
Toronto, Canada
At speeds above 55 MPH I feel a buzzing and hear the dome light vibrating. Here is what has been checked.
1. wheels rebalanced
2 off ground testing with weight on rear axle, wheels removed, brake drums removed = rear axle vibration
3.driveshaft u joints checked for movement -ok, - rear of driveshaft at pinion shaft= no runout, at pinion bearing=no play
4. front of driveshaft has little play in transmission output bushing, seal and bushing 1000 miles old- no leak
5 left axle bearing has very little play, right axle bearing a bit more play and a little runout(plus a very slight wobble)
6.right axle shows more c clip wear in-out movement

Summary - the vibration is felt at both ends of the axle housing equally but not as pronounced at pinion bearing end, This is an axle without wheels and brake drums for testing.

Will measure axle shaft at bearing diameter and check for bearing wear surface
Would the driveshaft u joint angles need to be verified?
Is there anything I missed
1986 SS, 90k miles, no accidents, always had vibration since I bought it about 8k miles ago
Thanks, in south eastern Ontario

#1073878 - 05/10/22 12:36 AM Re: Stock 86, High Speed Vibration [Re: guitars]  
Joined: May 2007
Posts: 5,130
Buick Runner Online content
10+ Year
Buick Runner  Online Content
10+ Year
Member

Joined: May 2007
Posts: 5,130
Dharma station 1 the Hydra
Did you check the driveshaft for balance? That includes clocking it to the same position it was removed from.


SBC powered 1987 Regal with TES headers, ZZ4 intake, ZZ4 PROM chip, mini starter, THM2004R, 2500 stall converter, 2040 cam, CCC system, and 3.73 posi rear.

2008 ex NPS P71 Crown Victoria, cop motor, cop shocks, cop brakes, and Jmod.

Never argue with an idiot.
They will just drag you down to their level and beat you with experience.
#1073879 - 05/10/22 01:01 AM Re: Stock 86, High Speed Vibration [Re: guitars]  
Joined: Feb 2008
Posts: 954
AkronAero Offline
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AkronAero  Offline
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Joined: Feb 2008
Posts: 954
Akron OH
X2 on Buick's balance check.

Also note that apparently MANY shops will replace a bad bearing cap assembly rather than change out the entire U-Joint. Sort of makes sense except not all bearing caps are interchangeable. As I mentioned in an earlier thread, my driveline shop finds several mis-matched bearing caps each week. I believe the outer bearing cap diameters are the same but the inner/bearing dimensions are not. I had an earlier shop build a NEW drive shaft for me and they mis-matched parts using different vendors. Took it back to rebalance and it still vibrated. Kept welding on washers to try to correct. Thus the stop at a pro shop where they put the yoke in a vice and twisted the other side all over the place. Inspect the u-joints for play (may not see when mounted?) and if any doubt swap them out for a new set (not expensive).

Good hunting and let us know.
Gordon
. .


1987 Aerocoupe. Frame-off, notched/mini-tub, 383 with AFRs @ 535HP/487TQ, March Serpentine, 304 SS headers (Jet-Hot) & 304 3" dual exhaust w/ Borlas, Janis 200-4R, TrueTrac w/ girdle and Moser 28, Hydroboost, computer delete, lowered, every part replaced or messed with (several times).
#1073881 - 05/10/22 01:24 AM Re: Stock 86, High Speed Vibration [Re: guitars]  
Joined: Dec 1999
Posts: 11,982
86ttop Offline
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86ttop  Offline
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Joined: Dec 1999
Posts: 11,982
Brooksville, Fl
Try this, I know, you're gonna think it's goofy, but an old time mechanic told me to put a hose clamp on the driveshaft at the rear u joint and mark the positions at the caps as 1-2-3-4 and spin it just as you already did and if the vibration is still there, move the hose clamp 1/4 turn,to the next mark and retry, if that takes care of it, you're good, if not, try the next position and so forth! Good luck and let us know how it turns out!


Leo Paugh
It's not an attitude, it's just the way I am.
POW*MIA
You are not forgotten
If things improve with age, I must be approaching magnificent. thumbs
#1073890 - 05/11/22 01:29 AM Re: Stock 86, High Speed Vibration [Re: guitars]  
Joined: Oct 2016
Posts: 110
guitars Offline
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guitars  Offline
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Joined: Oct 2016
Posts: 110
Toronto, Canada
It looks like the driveshaft yokes are welded off center causing oscillation at either end and the middle - 25 -30 thou. It's visually easy to see if the shaft is spinning. I checked all u joints - no looseness, C clips firmly seated, u joints check good, no missing internal spacer in bearing cups, no pinion/companion flange runout or looseness, Not sure if I have enough hose clamps to offset the wobble.

#1073898 - 05/12/22 01:05 AM Re: Stock 86, High Speed Vibration [Re: guitars]  
Joined: Dec 1999
Posts: 11,982
86ttop Offline
20+ Year
86ttop  Offline
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Member

Joined: Dec 1999
Posts: 11,982
Brooksville, Fl
Use just one large enough to fit around the driveshaft and see how it works, good luck!!


Leo Paugh
It's not an attitude, it's just the way I am.
POW*MIA
You are not forgotten
If things improve with age, I must be approaching magnificent. thumbs

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