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Clonking from rear

Those bilstein B4s are junk. They ride well but the rattling they make is unbearable. I had two sets and it was the same thing both times. I’ve got some KYB excel Gs on my car now and they’re quiet. Be sure to replace the lock nuts since they are considered one time use only.
 
Jack said:
14-15 years ago is a long time
You need to check it all

U joints or drive shaft center support bearing
Click to expand...

But it wasn't a long time 13 years ago.

Center support bearing has also been replaced and there's no-way it can make clonking noises like that. U-joints, I'd again say, not only does it not make a sound I can imagine they would, but surely it would also be affected by load and rpm.

I need to put my phone in the back and record this sound when I get a chance. Or maybe remove the rear seat and have my wife listen for the noise rolling along.

Maybe I need this:
 
I had a clunk that drove me batty for over a year. Ended up being the bolts for the upper shock mount. Was tight, but the tolerance was soo loose that the shock moved up and down. Couldn't duplicate in the driveway either.
 
It sounds like it could be a loose shock. I'd expect it during 'normal' driving, possibly a high frequency of occurrence of the knocking.

I believe the upper shock mount threads into the body, so if you pull the shock off the upper mount, I recall there's a hex head on the base of that stud that the shock mounts to...check that it's tight.

Of course by then you'd have found if the upper shock mounting nut was loose, but that could allow for noise.

Lower shock mount on the long bolt, if not fully tight, the lower end of the shock can move on the bolt.

Or if the bushing itself at the ends of the shock are allowing for too much movement.

When my '92 244 had this u-joint going bad (where it attaches at the rear axle / pinion flange), it was MUCH worse under acceleration when the joint needed to articulate but couldn't, so it would clunk badly. Steady-speed cruise, it was fine. This one slowly got worse, and I was pretty sure what I was going to find before I took it apart.

173891744.jpg
 
Thanks, upper damper mounts could definitely be it. I hadn't thought of that. I checked the lower mounts and bushes pretty well.

The car has been undersealed, so any movement would normally show up as smeared or cracked wax.

Regards,
Henrik Morsing
 
Hi,

Is it normal for the back-end of the 240 to be very lose side-to-side? Like it moves a lot sideways if I push it, and I can feel it driving as well. If I take a corner and there's a pothole in the road it feel like it slides.
 
That's not normal. There is some compliance side to side, no more than 2cm I'd say. When I push my car like that only the tire sidewalls move. When I'm loaded up in a fast corner like a highway onramp and I hit a bump I feel the rear end do a quick shimmy but it feels more to me like a toe change than the axle moving left or right.
 
Just found out there is something called "Chassis Ears"! Looks very impressive, will order a kit and see where I get with it.

www.tooltruck-uk.com

Alba Diagnostics Engine Ear and Chassis Ear

The Alba Diagnostics Engine Ear and Chassis Ear enhances workshop efficiency and customer satisfaction while saving time and reducing unnecessary warranty expenses. This advanced diagnostic tool allows you to listen to six under-chassis locations simultaneously during a single road test...
www.tooltruck-uk.com www.tooltruck-uk.com
 
morsing said:
Thanks, looking closer it is just the tyre walls flexing.
Click to expand...
morsing said:
Just found out there is something called "Chassis Ears"! Looks very impressive, will order a kit and see where I get with it.

www.tooltruck-uk.com

Alba Diagnostics Engine Ear and Chassis Ear

The Alba Diagnostics Engine Ear and Chassis Ear enhances workshop efficiency and customer satisfaction while saving time and reducing unnecessary warranty expenses. This advanced diagnostic tool allows you to listen to six under-chassis locations simultaneously during a single road test...
www.tooltruck-uk.com www.tooltruck-uk.com
Click to expand...
How do you mount that to rubber
 
I finally managed to fit some chassis ears and drive around a bit. It's not as clear cut as some people make out but I fitted three mics on each side and after a test run moved them to new locations.

As far as I can tell, it's the springs clonking. I was looking at the spring seats and mounts and, the anti-rust wax helps confirm this, nothing is lose or moving around. However, I am wondering a bit about the lower spring clamp. Could the springs be rotated wrong with regards to the lower clamp? The clamp has a shape, I assume it need to be rightly rotated for where the coil starts.

I have attached some photos.

IMG_0690.jpg

IMG_0691.jpg

IMG_0686.jpg

Regards,
Henrik Morsing
 
Very percular problem. If the car moves as you say I think there would be alot more wear marks on the spring perch and or tophat. As far as I know that spring looks fine as it's being clamped now.
 
Well, I give up, then. I just have no idea. Maybe I should buy a set of standard springs to fit just to eliminate these IPD springs.
 
I have replaced the upper spring seats. The old ones weren't bad, but at this point I just need to start replacing things. It didn't eliminate the noise, but it did dampen it, so that confirms it travels up the springs to the body.

I have bought a pair of those wheel stands you bolt on to the wheel hub so you can get access to the suspension fully loaded. I have a feeling maybe something it rubbing somewhere.

I think my next step is to remove the anti-roll bar and go for a test drive, if that doesn't help, I just have to remove one item at a time and inspect it. I might order some standard springs and see if that helps as well.


1776695663814.png (Example only, not my actual car)
 
Are you sure the panhard rod (tracking bar) bushings are good? Mystery clunking sounds can be associated with that. Unless they're badly worn it's sometimes difficult to pinpoint the source unless the suspension is loaded and the vehicle is in motion. Having it up on those stands may help you spot it. BTW Lowering springs have changed the rear end tracking geometry slightly. Ipd has an adjustable rod with poly bushings that may be worth thinking about. The cost of having new bushings pressed into your old rod could help offset the cost of buying the ipd one.
 
945T said:
Are you sure the panhard rod (tracking bar) bushings are good? Mystery clunking sounds can be associated with that. Unless they're badly worn it's sometimes difficult to pinpoint the source unless the suspension is loaded and the vehicle is in motion. Having it up on those stands may help you spot it. BTW Lowering springs have changed the rear end tracking geometry slightly. Ipd has an adjustable rod with poly bushings that may be worth thinking about. The cost of having new bushings pressed into your old rod could help offset the cost of buying the ipd one.
Click to expand...

'morning,

I already have the IPD bar. Bushings look perfect and it seems solid when pulling it. However, it is high on the list of items to remove and inspect.

But, it wouldn't really tie in with my chassis ears findings or the fact that new spring rubbers dampened the sound.

Thanks
 
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