Just bought a nice 2006 Cooper S hardtop with 70K miles...One owner....Have all repair receipts. ISSUE: clunking noise ONLY when I go over bumps, from the rear suspension. No equivalent sounds from front. Can't tell if I'm just hearing the normal Mini hard suspension sounds (and maybe the run-flats noise). Rear struts were both replaced 15K ago. I think all other rear bushings are original. Pulled both back tires off and looked over all bushings and every single nut and bolt I could get a wrench on. Everything looks look good (tight, solid, stock parts, Bilstein replacement struts, no cracks or wear marks on any rubber bushing, nice black color!) Also checked all interior plastic trim to be sure I wasn't hearing them rattling, but it's not that kind of noise.

THE NOISE: not a heavy, "big things underneath are probably broken" expensive sound. More like a medium size box of rocks or a box of loose tools in the trunk (if I had a trunk). Only over bumps. Hit a bump = clunk. Smooth road = quiet.

If this is the normal 2006 Mini experience, I will relax and enjoy my new toy. I've read about rear anti-roll bar bushings, etc going bad. Any thoughts would be appreciated. Thanks.

 

Rear sway bar, or strut mounts

 

^+1

 

Moving you to the Stock Problems/Issues area.

Could be a loose end link. Pull a tire, check the nut that connects the sway bar end to the end link that goes down behind the brake rotor.

 

Thanks for replies: I've crawled under both sides now twice, tightened everything I can see. Tied to shake and push anything I can touch. Nothing is loose. Assuming for now that it's not a loose bolt/nut, not wheel bearings (tires are rock solid), would my logical next step be to try a set of new ASB bushings and the trailing arm bushings and/or trailing arm bushing insets? I have no receipts from any rear bushing replacement.

Alternatively, I could spend that $100 to take car to mechanic and have him/her listen to the noise. Then probably buy parts. Not crazy about throwing parts at the problem, so am asking for any advice.

 

When driving can you reach your arm into the back seat and put your hand where the struts would be mounted? Do that first. If you can’t ‘feel’ the knock then there’s a good chance it’s not the struts. RSB could still be knocking against the floor of the car - is it aftermarket?

 

Good idea! I'll climb in the back and have the wife drive me over some bumps. Might be able to locate the source. Anti sway bar is stock, and bushings look fine...black, not cracked or worn. No gap or space between bar and bushing.

 

3 highly probable locations:

Shock top bushings are collapsed

Shocks aren't properly tightened and are clunking in the upper spring cup as well as blowing the hole out. Or spring isolators were omitted on reassembly of the rear shocks.

Sway bar bushings

I've not seen many failed rear endlinks on the first gen cars, but it seems to be a plague on the second gens, but that's not to be ruled out.

Control arms and trailing arms aren't a culprit, but have you looked at your exhaust? Broken hangers will cause a clunk on bumps.

 

Okay: first, I don't want to have to ride laying in the back of this car for long. Second, the sound is mostly coming from the back right corner area, and definitely somewhere outside the interior. Muffler hangers all look good. I only see two bolts at top of shock into the body and they are tight. I've not heard of spring isolators before, but I'll check for them tomorrow. I see what they are via Google, but unclear if I would see them once installed. Can I see them from underneath if I remove the tire? First owner receipts show a "rear shock mount replaced" and alignment in May of 2017, at a local import shop. Maybe I'll swing by there and ask them what they did. Thanks for the help.

 

I will put money on the strut mount / strut not having been tightened fully

 

Riding in the back of the car isn't going to tell you much that you don't already know, you need to get under the car and get hands on.

There is a lock nut on top of the shock assemblies in the rear, and you can only see it with the assembly out of the car. At this point you can also see if the shock top bushings are collapsed and failed.

The spring isolators are just rubber rings, one is at the bottom of the spring, the other is at the top under the perch. I've never seen the upper isolator being omitted, but I've seen multiple cars that the lower is missing.

I would also recommend disconnecting the rear end links from the sway bar to articulate the bar and feel for play in the bar bushings, and while the end links are disconnected check that the plastic injected cup isn't loose in the steel eye of the link causing a clunk.