Okay some of you have probably seen my other threads, but I've been struggling with my rear suspension clunking for a while. I get clunks every time I go over speed bumps with one wheel on the bump and one wheel off. It does not happen when both wheels go over the bump at the same time. I also get clunks when turning into inclined driveways, and very hard cornering. Sometimes, when I put the car in reverse and start backing up I occasionally get a clunk.

I have eliminated almost everything. I took a jack, prybar, and wiggled, pried, everything back there. Checked all the bolts, even sprayed some lube on all the bushings for good measure. Strut mounts bushings and struts: good (and recently have been replaced) Rear sway bar end links and rear sway bar bushings: good (recently changed the sway bar bushings and they are well greased) I tried prying on the trailing arm bushings. I couldn't get them to clunk, but they did seem a little too easy to move around. These bushes, afaik have NEVER been replaced in the 18 years the car has existed, and my car has 134,000 miles on it. The rear control arm bushings have also NEVER been replaced.

Logically, does it make sense I should go about replacing these? I think I've eliminated everything else back there. Even if they aren't causing all the clunking, they are certain to be bad by now right?

 

Especially because you mention this happens when each side is being acted on differently, I would suggest to start with replacing the swaybar endlinks. Although I don't have this experience, yet, on our Mini - replacing the swaybar endlinks quieted suspension clunks on our 05 Volvo V70R and 05 Town&Country. The Volvo ate the front swaybar endlinks every 15-20k miles or so, until this last set of Lemforders that I installed (I think they were Lemforders).

Good luck!

 

I forgot to add it in but I replaced the sway bar endlinks as well. Didn't solve the clunking.

 

Based on your last thread, my suggestion is to find a competent and trusted local mechanic that can help with troubleshooting. Trying to pinpoint where a noise is coming from is near impossible over the internets.

Either that, or have a willing friend ride around in your back seat to see if he can figure out the location where the sound is coming from. Getting an accurate location will be key to determining the cause.

 

I've tried several mechanics, the issue is even the local ones trusted here have given me several different answers as to what it could be.

I had a friend sit in the back seat and he told me it feels like there is something popping under the seat.

I'm still wondering about the RTABs bushes though because through process of elimination I've checked literally everything else and they are the only original bushings left on the car. At almost two decades old 130k+ miles and many autoX days I'm sure they HAVE to be bad.

Is there any reason why they wouldn't be an issue?

 

If you're 100% sure its under the seat, could be the control arm bushings binding up. They connect tot he body up under the seat to the subframe. Maybe try pulling the bolts out and lubricating the frame where the bushing bolt go through.

Again, though, crap shoot....

 

That's something I've yet to try. Is it worth replacing the RTABs and control arm bushings anyways though because of age?

 

I have seen numerous threads about clunking after servicing or replacing a suspension component. Recently I learned that BMW's method for torqueing fasteners is to have the suspension under compression before torqueing. Meaning that you should not have your wheels/suspension hanging when you do the torque to spec. I will include a couple of reference you tube videos that hopefully may help with the problem.
Although these may not be the same vehicle the same principles should apply.
I hope they help, let us know how you make out.
Steve

 

Appreciate the advice. I replaced the rear trailing arm bushes a couple days ago. The clunks are gone and the car handles better, HOWEVER, I can definitely still hear something binding only on the right rear side. I'm getting tired of working on the car constantly, so I'm going to put this off till the next oil change I have to do. But I will pull the struts, bolts for the rear control arm out and relubricate and retorque everything with the suspension under compression and hopefully that loosens up whatever is binding up.

 

Did you figure it out? I have the same issue.

 

Going to revive this. Did either of you find your solutions.

I am planning on the rear trailing arms. And I think I realized my mistake in not torquing after loading. So I am looking for some ideas of where to look before I can get back under.

 

I'm curious as to how anyone torques the bolts under compression because there's no way to get under the car when parked. Does everyone use a drive-on 4-post lift?

 

I have a 2-post lift, and then I raise a hydraulic transmission jack putting pressure up via the wheel or wheel hub until that corner of the suspension seems under typical load and then tighten the bolts.

Wheel hub stands would work well, I think, and still allow good access to tighten all the bolts.

 

The cheap diy way is to use/build a car ramp. Not a fan of these for doing a lot of work, rather use jack stands, but for this application it serves it's purpose.

 

+1^^^
I don't have a lot of fancy tools let alone garage space - But I do recall doing rear suspension work and having the wheels under load by jacking up the rear and stacking a few 2"x6" length of wood under each wheel before letting down the jack. Of course placing jack stands poised in place for safety.