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back end sway under acceleration

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Tom Willard

New Member
Joined
Nov 6, 2002
Messages
28
I have a GN(48k miles)with stock suspension and airbags. 18psi right side, 8 psi left. Under hard acceleration the back end wobbles violently left to right. Sometimes it's scary enough that I have to let off of it. What causes this?
 
Wobble

Probably bad bushings in the lower control arms. Maybe uppers, but lowers are easier to get to, and I think they are more likely to cause wobble. One step up, and pretty cheap, are the 1LE bushings from a Camaro/Firebird. Next step would be poly bushings, which may squeak. 1LE lower control arms are an improvement, or you can box your stock arms, or you can buy any number of "high performance" arms from Lakewood, Hotchkiss, Edlebrock, etc. Some of the aftermarket lower arms will come with bushings. It's probably not the arms causing the wobble, though, bushings more likely. The stock arms can cause "tramp", on launch, though. This is just my thoughts, others may have, and probably will have, different opinions. But it's free advice, what can you expect?
 
More opnions on this issue please. Mine does the same thing but only when i'm at 40 to 50MPH and I get on it. The car feels like it wobbles from left to right. On normal crusing the car runs fine.
 
My car does this too. Only when WOT from 30mph up. It does not do it everytime. I always thought that it was caused by the 275/50's.

I do have new poly bushings for the rear arms. Maybe I'll get to do that this winter.
 
I've seen this many times before on friends cars. Almost always the same symptoms that you guys are describing, and after riding in a couple of them I can relate how scary of a ride it can be. Whenever we'd have this problem, changing the rear upper and lower control arm bushings would cure it. Unless the moutning holes for the bushing were Ovaled out from really bad bushings and excessive wear.
Hope this helps a little.

Patrick
 
My car used to suffer from this . At that time i along with others who suffered the same on this board came to the conclusion that it was the rear tires. I used to run BFG 275/50 15s. The others did too. Mine did it with polys on the stock control arms and an ATR sway bar so that wasnt it.I now run GNX look alike s with different tires altogether.
 
Originally posted by Louie L.
My car used to suffer from this . At that time i along with others who suffered the same on this board came to the conclusion that it was the rear tires. I used to run BFG 275/50 15s. The others did too. Mine did it with polys on the stock control arms and an ATR sway bar so that wasnt it.I now run GNX look alike s with different tires altogether.

I also run GTA/GNX look alike's, with 245/50/16. Does it suffer from the same problem with this setup?
 
I thought it may have been the BFG's too on mine, but can't recall. Probably the stock control arms and bushings too I guess :-) Replaced with Hotchkis and Metco and it's never happened since.

TurboTR
 
I run 16" GTA wheels and my car lauches straight as an arrow. Try letting all the air out of the air bags for a test first, also consider checking your shocks and bushings out.
 
Originally posted by Grumpy
wornout clutches in the posi unit :eek:

That's what I was going to suggest. Usually if the bushings were bad, they take an instant set when loaded and typically you have to countersteer a steady amount. The rear of the car is more likely to wobble as the power is not evenly and consistantly distributed to the tires.
 
I have delt with a couple of vehicles with the same issues. I replaced the bushings on the uppers and lowers or replaced the control arms completely. This along with proper air in the air bags and tires and this fixed these issues
 
Originally posted by Louie L.
My car used to suffer from this . At that time i along with others who suffered the same on this board came to the conclusion that it was the rear tires. I used to run BFG 275/50 15s. The others did too. Mine did it with polys on the stock control arms and an ATR sway bar so that wasnt it.
Yep mine did the same thing with "regular" Radial TA tires in that size. I have since went to a BFG DR(same size) and no longer have the problem.
 
I was about to say, that I too had the BFG 275/50's radial T/A's and had the same problem. I have the hotchkis lower arms and new bushings. I changed to different tires/wheels and the problem is gone. But with the 275/50's on the stock GN wheels I could get the car rocking side to side with me lightly pushing on the rear of the car in the garage. It was kind of like driving on a set of balloons. :eek:

Derrick
 
too wide of tire for rim ...no suspension work will cure that

been there done that not fun esecially higher powered cars...scarry
 
I too have had a severe case of this on two outta three of my TR's. Both cases it was the rear control arm bushings. I always replaced all of them at once, with Energy Suspension replacements. These can be acquired through Summit, Jeg's, or usually any local speed shop.
Yes, they do have a tendency to squeak more, but it by far beats the alternative of feeling like you're on a rollover roller coaster at Disney World!!! The squeaks can be quieted by use of a little lube, and the car definitely rides much better.
 
I have boxed arms atr rear bar polly bushings and stock front bar (at the time) and only time mine did it was when I put 265/50/15 bfg's on a 7" wheel

I changed to narrower tire and was fine...so for gigles I mounted the 265's on my a/r 15/8.5 rims and no problem

Its more of a short sidewal too wide tire than a taller tire since the sidewall dont get as distorted on taller tire

other words a 275/50 on 7" wheel will be less stabile than a 275/60 tire on same wheel
 
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