Hi: 2004 MCS w/ 160K. Chasing a 'clunk' in the rear suspension. Have already replaced the struts, mounts, and bump stops. Torqued everything to spec. Am now replacing the sway bar end links. Should I replace the sway bar bushings? I do not detect sufficient play in them to create the clunk and I'm scared that I might break one of the mounting bolts. Will check the nut that secures the struts to the top mount. What about the trailing arm mount and control arms? Thoughts, particularly any guidance on how best to limit the possibilities? Yes, I know how difficult such questions can be to answer without the car in front of you. Thanks.

 

Having the same issue with my '04 since switching to poly bushings. My end links and sway bar bushings are also new. I've also replaced struts. Everything is torqued to spec and I cannot locate the source of the "clunk" either. I would be interested in knowing whether or not your trailing arm mounts may not be torqued correctly (74 ft lbs). I realize this information doesn't help you in any way but if you nail down the cause of your "clunk" I would appreciate a heads-up. It's driving me crazy also.

 

None of my trailing arm mounts have been disturbed. I am nonetheless thinking of installing the 'inserts' in the forward mounting points. Not inclined to touch the lateral control arms (upper & lower) unless the car can't be aligned, or my mechanic suggests otherwise. (I'm having the front subframe dropped to replace the rear main seal, clutch, all ball joints, and the sway bar bushings.)

 

For me clunks have always ended up being the sway bar. So new bushes and end links...

 

Clunks at the rear of my buddy’s R53 was the top nit of the struts. One worked it way loose.

 

JAB 67, dependent on your build date your rear control arms are not adjustable and do not affect alignment. If your build date was after 11/04, the control arms will have a cambered nut that will allow slight camber adjustment. If your build date was prior to 11/04, then the only adjustment in the rear is the toe-in that is accomplished by moving the trailing arm mounts.

 

Cooper: Thanks; Yes, I understand that. My build date is March of 04. However, I have read that if excess camber is suspected, such as by excessive inner tread wear, it may indicate the the control arm bushings are worn and because they are not adjustable you need to either replace the bushings or the entire arm. Have I misunderstood that?

 

You're correct. Worn control arm bushings could certainly affect camber/tire wear but they would have to be pretty far gone to do that. The upper and lower control arms are all the same part (with the exception of the one with the leveling sensor) and would not have to be replaced unless they were bent. Camber adjustment is the primary reason people switch to adjustable control arms on the bottom. That's not really necessary unless you track the car. I switched my trailing arms and control arms to poly bushings simply as part of my rebuild. I will say I notice a stiffer ride and more road noise. I had it aligned after the bushing installation and have found that the alignment shop apparently over-tightened one of the left side trailing arms bolts damaging the threads and now I'm unable to torque it to spec. That's the reason I asked about your trailing arm bolts.