Rear end wobble after axle drop
#1
Rear end wobble after axle drop
Hello,
So where do I begin.. I have a 98 Firebird V6 with about 95k on it. Motors strong, trans is strong, and drive line is strong.
About 2 years ago, I blew the rear. Broke the pinion rod in half, which then caused everything else to just yoke up. Needless to say, I rear built the rear. Put a 3.73 posi in. The rear is great, gave the car a hell of a lot more pick up, and the posi is just fun. I also then put a set of American Racing rims on, with 10.5" rears and 9" in the front, 17" rims, not the 18". Also put Sumitomo tires that are rated up to 183mph.
Now to rebuild the rear, I ended up having the drop the axle, not going to get into that because the story as to why I had to do this is irrelevant.
After the rebuild, we put the rear axle back up, torqued everything down to spec, lubed up all the bushings and replaced the sway bar links. But for some reason, the rear end wobbles like hell now. The struts are good, the car isn't sagging or anything like that, doesn't bounce up and down or anything. However, the car wobbles side to side horribly, to the point that I can't take it on the highway over 55 or it feels like the rear end is going to whip out. Bumps have became extremely rough, and there is a loud clunk.
I have been in school and working full time, so I haven't had a chance to tear anything apart to check bushings or anything, with the traction bar or anything, but I did replace all of them on the sway bar. Like I said, everything is torque to spec that the Hanes has listed. Other than the posi and rims/tires, this car is completely stock. This never did this before I dropped the axle. Only things I disconnected were whats necessary to remove the axle, no bars were completely removed.
Any advise as to what to check?
I might be able to get pictures from the orginial teardown in a little bit, to show what was still attached and what was removed.
Many Thanks
So where do I begin.. I have a 98 Firebird V6 with about 95k on it. Motors strong, trans is strong, and drive line is strong.
About 2 years ago, I blew the rear. Broke the pinion rod in half, which then caused everything else to just yoke up. Needless to say, I rear built the rear. Put a 3.73 posi in. The rear is great, gave the car a hell of a lot more pick up, and the posi is just fun. I also then put a set of American Racing rims on, with 10.5" rears and 9" in the front, 17" rims, not the 18". Also put Sumitomo tires that are rated up to 183mph.
Now to rebuild the rear, I ended up having the drop the axle, not going to get into that because the story as to why I had to do this is irrelevant.
After the rebuild, we put the rear axle back up, torqued everything down to spec, lubed up all the bushings and replaced the sway bar links. But for some reason, the rear end wobbles like hell now. The struts are good, the car isn't sagging or anything like that, doesn't bounce up and down or anything. However, the car wobbles side to side horribly, to the point that I can't take it on the highway over 55 or it feels like the rear end is going to whip out. Bumps have became extremely rough, and there is a loud clunk.
I have been in school and working full time, so I haven't had a chance to tear anything apart to check bushings or anything, with the traction bar or anything, but I did replace all of them on the sway bar. Like I said, everything is torque to spec that the Hanes has listed. Other than the posi and rims/tires, this car is completely stock. This never did this before I dropped the axle. Only things I disconnected were whats necessary to remove the axle, no bars were completely removed.
Any advise as to what to check?
I might be able to get pictures from the orginial teardown in a little bit, to show what was still attached and what was removed.
Many Thanks
#3
It does this when your on the throttle or not, it has nothing to do with throttle, I don't believe anyway. Also, it seems like when I hit about 65-70, it feels like a tire is off balance, but I've had the tires checked by 4 different garages. There's also no body roll either, the car sits completely flat going around a corner. I can take very sharp corners at 45 full throttle, and the new tires just stick to the road, but if there is any type of bump, the car will fly all over the place.
#4
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Long ago I installed a set of bolt in control arm brackets and mine would do the same thing. I decided to weld them and problem solved. From my experience it sounds like something is loose allowing it to shift from side to side.
Just dumb question but was the suspension loaded when you torqued everything? I'd look at control arms, panhard, and tq arm bolts and bushings one more time just to be certain nothing is loose and none of the bushings are shot. I don't know if uneven tq or misslignment of the sway bar would cause this or not.
Just dumb question but was the suspension loaded when you torqued everything? I'd look at control arms, panhard, and tq arm bolts and bushings one more time just to be certain nothing is loose and none of the bushings are shot. I don't know if uneven tq or misslignment of the sway bar would cause this or not.
#5
Make sure you didn't do something that would be my speed which is leave the c clips out so the calipers are holding the axles in. Also put a micrometer on each tube and check the runout of your axles.
#6
Long ago I installed a set of bolt in control arm brackets and mine would do the same thing. I decided to weld them and problem solved. From my experience it sounds like something is loose allowing it to shift from side to side.
Just dumb question but was the suspension loaded when you torqued everything? I'd look at control arms, panhard, and tq arm bolts and bushings one more time just to be certain nothing is loose and none of the bushings are shot. I don't know if uneven tq or misslignment of the sway bar would cause this or not.
Just dumb question but was the suspension loaded when you torqued everything? I'd look at control arms, panhard, and tq arm bolts and bushings one more time just to be certain nothing is loose and none of the bushings are shot. I don't know if uneven tq or misslignment of the sway bar would cause this or not.
I did torqu the sway bar a little past spec (by like 2-3lbs) and that seemed to help a bit.
#7
I don't have a micrometer, so I can't do that, but the shop that I had shim my rear, said that the axles and the actual rear it's self is fine. I know that I need to have my gears re-shimmed, because they do have a small amount of slack, but simply from it being broken in. The new chunk and gears only have about 2000 miles on them.