Excessive Rear Suspension Noise Over Pavement Joints

[blubox03]

Over the last year, I have experienced an increase in noise in the rear suspension, esp. over joints in the road at highway speeds. I have replaced sway bar bushings-no difference, one rear trailing arm-no difference, and am about to replace one rear control arm (which has a torn rubber boot). I have on order new drop links for all 4 corners which I will be replacing next week. I am starting to think it may be the struts? I have read on other posts that the struts really don't go "bad" until you se them starting to leak. Is this true? There is no leaking on any struts currently. I have been reading about the top mount for the rear struts - is this a common part that goes bad? 03 986 with 62,000 miles. I do track the car about once a month for the last 2 years. I have made sure all is tight and to prober torque. The sound is a loud bang (louder than what is used to be) over joints in the road - this does happen even at low speeds. The car handles great. What do you guys think? Thanks Jason.

[number9ine]

I've had strut mounts go on non-P-cars I've owned in the past, and a crashing noise over bumps is definitely a symptom. As far as your struts go, they can definitely show their age without failing. Does the car hop when you hit expansion joints, or continue to track straight? Do you feel unnecessary rebound when camber changes abruptly in turns? I would say those are signs that you should replace the struts.

Do you feel a lot of driveline vibration? If one of the motor or trans mounts has failed, you'll get some nasty noises over bumps. Considering your car's age and track history, I wouldn't rule this out even if it's not the cause of your current problem.

You mention you track the car. Are you running on the track tires, or do you have a separate set for the street? What brand and spec are they? The PS2s my car was sold with made a horrific hollow banging noise over every rut, expansion joint, and pothole they found--even with zero miles on the tread. Currently running Contis that are quiet as a mouse by conparison. As I'm sure you know, once tires are heat-cycled a few times they become very loud and hard.

Hope this helps.

Mark

[blubox03]

Thanks for the suggestions. I did change my motor mount last year. I don't really have much vibration and don't think this is related to trans mounts. I just changed driver side rear trailing arm tonight and no difference was heard. I also re-torqued my 3 bolts on top of strut to 27 ftlbs, they were a little loose, but still no difference. Your suggestion to the tires makes sense. I do have a different set of rims and tires for the track. I am starting to think it could be a tire issue. Currently running Conti Sport II with 5/16 tread remaining in the rear (50% left). Plan to put new drop links on this weekend and will see if that changes anything...

[N41EF]

Did the links help the noise? My 03S has a noise that sounds like it is coming from the right rear. I changed the oil and checked the tourque on everything I could find. I noticed the right sway bar end link would wiggle, but the left one was tight. I think that might be the source of my noise, I get a thunk sound when the right rear is on a bumpy road. Thanks, Chuck

[EZ Aire]

I don't buy into the "Struts don't go bad" idea. I changed mine out a month or so ago and could easily compress the struts just by holding them and opening and closing them repeatedly, while the replacements were not compressable at all by hand.

I also have the clunking and changed all of the parts you are and I still have it to some degree on rough streets.

Good Luck.

[Goslo]

This may be too late for you - you may already have corrected the noise. Had a similar noise and rough ride on my 2001 986S, and after much checking changed out both rear trailing arms to correct the problem. The test is to grab the traing arm(s) and shake it hard with weight on the wheels. If it moves the rubber bushing is likely collapsed. Had never seem what I thought were solid bushings collapse like the fluid in them leaked out. There was no evidence of leakage before removing them. Good luck.

[59coupe]

Check your wheel bearings as well. I had what sounds like a similar issue. Diagnosis, bad wheel bearing.

Keep the Faith "Z"

[blubox03]

I changed tires and that solved the loud clunk in the rear! All that and it was just **** tires :cursing: