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240 rear clunking noise

Patestrickland

Patestrickland

Member
Joined
Oct 25, 2017
Location
Emerald Isle, NC
My 93 240 has started making a loud clunking noise coming from somewhere in the rear suspension. It only makes this noise when I go over speed bumps or super big bumps. I replaced the shocks and it still makes this noise. I tightened everything down in the rear and still made the noise. I tried to do some research and found that it might be the trailing arm bushing. Could the be the culprit?
 
Mine makes this noise because of the rear axle colliding with the exhaust. I have overload springs, and PO had a shop weld a new 2.25 stainless catback system, resulting in collision. Going to have my shop go over-axle. Raise the car and see if there are collision marks on either the exhaust or axle.
As others have said, trailing arm bushings are also the common culprit.
 
I had this happen after replacing shocks. Double checked everything. Everything was snug.

Medium length story made shorter - the upper shock bolts mount through the subframe. You can have them *tight* on the shock, but it's easy to accidentally loosen them where they bolt to the subframe - separate nut. Then a gas pressure shock like a Bilstein will keep that under pressure when the car is sitting still, and you won't notice the slack. But when you go over a bump, it goes from compression to rebound - and the forces reverse briefly, making it clunk.
 
JohnMc said:
I had this happen after replacing shocks. Double checked everything. Everything was snug.

Medium length story made shorter - the upper shock bolts mount through the subframe. You can have them *tight* on the shock, but it's easy to accidentally loosen them where they bolt to the subframe - separate nut. Then a gas pressure shock like a Bilstein will keep that under pressure when the car is sitting still, and you won't notice the slack. But when you go over a bump, it goes from compression to rebound - and the forces reverse briefly, making it clunk.
Click to expand...

This also happened to me, but it was very apparent when driving on bumpy roads, and with the rear seats down, it was acoustically obvious where the noise was coming from, sounded like a loud rattle.
 
IansPlatinum said:
This also happened to me, but it was very apparent when driving on bumpy roads, and with the rear seats down, it was acoustically obvious where the noise was coming from, sounded like a loud rattle.
Click to expand...


I previously had this problem but both sides are tightened. I swapped my old rear shocks on my car last night and the sound over speed bumps wasn't there anymore. Maybe it's because my stiff bilsteins caused something to rattle and my soft old shocks didn't.
 
Patestrickland said:
I previously had this problem but both sides are tightened. I swapped my old rear shocks on my car last night and the sound over speed bumps wasn't there anymore. Maybe it's because my stiff bilsteins caused something to rattle and my soft old shocks didn't.
Click to expand...

I'm pretty sure the rear shocks are all supposed to have the same fully-extended length eye-to-eye, but maybe the bilsteins are longer and are allowing your axle to hit that exhaust on full extension. get under there and you'll be able to immediately tell if it's that or just bushings based on wear marks on the axle/exhaust

the higher damping ratio on the billys could also be transmitting more force to your rubber bushings and making them clunk too

are they yellow HDs or touring?
 
There are only a couple of suspects - the upper or lower control arms.

If the TABs are original, they are the likely cause.

The 'torque arms' aka upper control arms could also have bad bushings.

In my case, it was the FRONT bushing on the lower control/trailing arms.

If all the bushings are original, its a very good possibility that they are all in some state of failure.
 
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