Hello,

My 1994 W124 keeps making a groaning sound in the left front. It is apparent when braking to a stop and when I press down on the left fender. I also sometimes hear that sound or a clunk when going over potholes. The first culprit is usually the LCA ball joint, so I replaced the LCA on the left side. The sound persisted regardless.

Here's the list of what has been replaced/checked on the car so far:

-Left LCA replaced
-Right LCA replaced
-Sway bar bushings inner and outer (inner bushings sit very firmly. The outer ones slide on very easily and there seems to be a bit of play, as the bar was worn to bare metal underneath. Recoated the sway bar with few coats of paint.)
-Sway bar "hangers" are OK, no signs of breakage
-Unrelated, but let's rule those out: idler arm bushing has been replaced, steering linkage inspected, no play.
-Strut mounts inspected, no play, no cracks
-Top strut nuts tightened just to be sure

The left shock makes a "gurgling" noise when I press on the fender - even if it's bad, I don't think it would be a culprit for that sound. I undid the top mount and inspected the shock - it has considerable resistance going up and down, does not seem to be shot despite the sound. The shocks were replaced with Bilstein parts before I purchased the car (late 2021).

The steering and suspension feel very tight and the car does not wander - I had a very bruised 300D in the past and that one and the current car are like night and day.

My money's on the sway bar being excessively worn on the outer bushing side, but I'm very curious about your suggestions before I go sourcing a new sway bar or smaller diameter bushings (if I remember correctly, there are several diameters. The ones I currently have on the vehicle are VIN appropriate). Any help is greatly appreciated.

A groaning sound in the front suspension is the ball joint of the upper control arm.
There is to much pressure on the lower control arm to groan, it just wears out silently.
The upper control arm is not under pressure and can groan really loud.

Rob

Hi Rob, I have a W124 - no upper control arm in the front.

Sorry I looked at the W123.

With the W124 it is probably the part that attaches the strut to the frame or the strud/damper itself.

It has to be a part that is not under heavy load.

It can be difficult to find where it comes from.
I use a homemade detector with 6 guitar microphones, cheap and effective.


Rob

KJ:

Consider disassembling the sway bar & bushings enough to lubricate the bushings, both the ID and the surfaces of the bushing in the clamps.
Use glycerine or a rubber lube such as Ru-Glide. If the bushings are the source of the noise, the lube should give, at the least, a temporary reprieve.

Hello Frank,

When installing the bushings, I used some dish soap. After recoating the bar, I used the same approach. I went for a test drive right after the installation and the noise persisted, even tho the bushings were coated with soap on the inside.

A discussion on another forum recommended 1) winding the bar with teflon tape or 2) coating with epoxy and sanding down to diameter. Has anyone used those approaches? I'm not very partial to welding the sway bar, to say the least.

According to the exploded drawings of the W123s front end, it looks the same as the W126?

From the LCA, there is a "Breaking Strut" that goes back to an aluminum housing with a bushing at the end. That bushing is your likely issue. I don't see that item among the ones you have addressed. The 'clunk' on breaking and potholes is the tell.

Hey Doug, I have a W124.

My bad.

For future reference - if anyone runs into the same problem and the groaning/clunking persists even after ball joints were replaced, check your strut. Unlikely culprit, but that's what caused the problem for me. I replaced the strut with an OEM Bilstein component and all funky noises are gone.