thumping sound - speed dependent and steering return

[jrobie79]

So i just got my car back on the road - all new bushings in the rear (poly), H&R race and billy sports, got everything aligned at Bavarian Performance group.

Noticed when I'm driving I have a thumping sound that is speed dependent, which makes me think its a tire problem, but I wanted to confirm. I'm pretty sure I tightened everything up back there, ie half shaft to diff bolts, hub bolts, lug nuts, etc... anything else that might cause this.

also I do not have power steering, but it seems like my steering wheel is reluctant to turn back to center coming out of a turn unless I give it some help. I have all new tie rods, control arms, and powerflex eccentric CABs. Just recently aligned, the only thing not new is the upper strut bushings/mounts or whatever they are called with the three sutds into the strut tower. Could this be the reason its not returning? I hear no physical binding, just wont return.

Thanks!

[KenC]

Did you do anything with the driveshaft? Thumping could be that it's not tightened down all the way.

Non-returning from wheels are almost always due to a missing washer between the strut and the upper strut bearing race cover.

[jrobie79]

I replaced the driveshaft, with one that was in better shape than my previous...my previous one the CSB was all torn up, the one I bought (used) had some stiffness in the u-joints, but not nearly as much as my old one and the CSB looked pretty damn good, bought it from someone on here too. I replaced the guibo and CSB too.

and I thought I made sure that washer was in there, it is item # 8 in the picture right:

[KenC]

The u-joints in your driveshaft are binding. It could also be out of balance. Did you pre-load the CSB?

Yes, #8 is the washer that most people forget. The upper strut mounts should spin with ease.

[jrobie79]

I don't remember my old driveshaft making any noise, and it is definitely in worse shape than this one, and I thought I preloaded the CSB (put it forward a little before tightening the CSB frame to the body)....oh well, I knew I'd need a new driveshaft sooner or later, just can't afford a reman one yet

[KVF]

U-joints being firm is not a test of their condition. Binding/inconsistent firmness, play, or otherwise not feeling smooth are the issues to look for. Smooth and firm without any play is actually good. Additionally, you can only test balance via a shop. Sounds like you should toss the old ds back in with a quality guibo and see how that works.

[jlevie]

If the cause is the drive shaft, the thumping should get worse when you subject the drive train to high torque. Acceleration in the lowest gears with a generous amount of throttle should aggravate the issue.

[jrobie79]

I notice it in neutral rolling to a stop, like on an exit ramp coming from 70mph to 20 by just rolling, no engine braking or brake pedal

[KenC]

I notice it in neutral rolling to a stop, like on an exit ramp coming from 70mph to 20 by just rolling, no engine braking or brake pedal

Then it's probably just unbalanced.

[jrobie79]

I'll take a look, I am 99% positive I matched up the white marks on each end of the D/S, will it be catastrophic to keep driving like this till the weekend?

[jlevie]

Unless it gets worse I wouldn't worry too much.

[jrobie79]

Failed the mention the car sat for about 5 months before I put it up on jack stands....flat spotted the tires maybe? Gonna swap my winters on it to see if it goes away.

[jrobie79]

figured it out, warped rotor coupled with shitty tires, swapped both, no noise