Hearing subtle "clunk" when slowly going over speed bump
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Member
Joined: Oct 2002
Posts: 107
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From: San Diego, CA
2001 E55 AMG
Hearing subtle "clunk" when slowly going over speed bump
A friend lives in a townhome complex and it has a lot of speed bumps. Whenever I pick him up to workout early in the morning, I hear a subtle "clunk" when I very slowly go over a few speed bumps. By slowly I'd say 2 m.p.h. - I almost completely stop before driving over them. The car is quiet then (i.e. minimal engine noise and no road noise) but I can hear a distinct "clunk" from the rear end somewhere.
Part of me thought it was gas sloshing back and forth in the tank?
Other thoughts?
[T-Squared recommended I use two-sided tape to tape down any moving parts in the rear trunk, etc., like the jack, etc....I did that but still hear the noise.]
Part of me thought it was gas sloshing back and forth in the tank?
Other thoughts?
[T-Squared recommended I use two-sided tape to tape down any moving parts in the rear trunk, etc., like the jack, etc....I did that but still hear the noise.]
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12' W204 C63 AMG coupe "T-Rex", 12' W451 Smart Fortwo Pulse (99' W202 C43 AMG + Ultima Can-Am sold)
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1999 C43, 2008 P30 E63, 2014 SQ5, 2024 Model Y Performance
+1, your symptoms do sound very familiar with the bushings in the rear control arms giving out.
I found this on another thread, this is a test some guy did:
I could not localize the sound by ear except to front of car. I did finally isolated my problem with pieces of 2x4 on the driveway.
Driving over 2x4 with both front wheels hitting the 2x4 at same time => clunk
Drive over 2x4 with left front wheel only => no clunk
Drive over 2x4 with only => clunk
Drive over 2x4 with rear wheels right/left/both => no clunk
Removed bar links one at a time => no change to above tests. This was a driveway test only. I did not drive the car on the street with disconnected link.
The clunk disappeared if I applied the brakes lightly on driveway tests and over the road.
Severity of the clunk varied a little with direction and angle of turning.
I sometimes had a tiny/miniscule amount of the highway speed steering wheel shimmy that is a typical symptom of failed thrust arm . But not every trip, and only for short periods, say 3 to 10 seconds.
Checked ball joints on thrust arms and control arms with a pry bar. I thought maybe some play in the right thrust arm ball joint but not definitive. Yes, I know that even tiny movement indicates a bad ball joint, but this, if it existed was so small that I was never sure it actually had moved. And by this time I knew it was a right front problem, so perhaps the power of suggestion.
Could not see any signs of bushing leakage, no visible stains.
Checked movement / looseness of thrust and control link bushings with a pry bar & push/pull by hand - no difference found between them.
Checked - push pull at 12-6 & 3-9 o'clock on wheel and smoothness of spin.
Also checked for pad rattle, strut bearings, brake air ducts in front facia, loose front end trim pieces, etc. etc. ad infinitum.
I found this on another thread, this is a test some guy did:
I could not localize the sound by ear except to front of car. I did finally isolated my problem with pieces of 2x4 on the driveway.
Driving over 2x4 with both front wheels hitting the 2x4 at same time => clunk
Drive over 2x4 with left front wheel only => no clunk
Drive over 2x4 with only => clunk
Drive over 2x4 with rear wheels right/left/both => no clunk
Removed bar links one at a time => no change to above tests. This was a driveway test only. I did not drive the car on the street with disconnected link.
The clunk disappeared if I applied the brakes lightly on driveway tests and over the road.
Severity of the clunk varied a little with direction and angle of turning.
I sometimes had a tiny/miniscule amount of the highway speed steering wheel shimmy that is a typical symptom of failed thrust arm . But not every trip, and only for short periods, say 3 to 10 seconds.
Checked ball joints on thrust arms and control arms with a pry bar. I thought maybe some play in the right thrust arm ball joint but not definitive. Yes, I know that even tiny movement indicates a bad ball joint, but this, if it existed was so small that I was never sure it actually had moved. And by this time I knew it was a right front problem, so perhaps the power of suggestion.
Could not see any signs of bushing leakage, no visible stains.
Checked movement / looseness of thrust and control link bushings with a pry bar & push/pull by hand - no difference found between them.
Checked - push pull at 12-6 & 3-9 o'clock on wheel and smoothness of spin.
Also checked for pad rattle, strut bearings, brake air ducts in front facia, loose front end trim pieces, etc. etc. ad infinitum.
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Joined: Oct 2010
Posts: 209
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From: San Diego, Cali
AMG 2002 E55, 1997 E320
A friend lives in a townhome complex and it has a lot of speed bumps. Whenever I pick him up to workout early in the morning, I hear a subtle "clunk" when I very slowly go over a few speed bumps. By slowly I'd say 2 m.p.h. - I almost completely stop before driving over them. The car is quiet then (i.e. minimal engine noise and no road noise) but I can hear a distinct "clunk" from the rear end somewhere.
Part of me thought it was gas sloshing back and forth in the tank?
Other thoughts?
[T-Squared recommended I use two-sided tape to tape down any moving parts in the rear trunk, etc., like the jack, etc....I did that but still hear the noise.]
Part of me thought it was gas sloshing back and forth in the tank?
Other thoughts?
[T-Squared recommended I use two-sided tape to tape down any moving parts in the rear trunk, etc., like the jack, etc....I did that but still hear the noise.]
