Clanking noise from rear of 300TE: What's the source?
 

Vehicle is a 1992 300 TE with 133k miles on it.

When I go over speed bumps and/or humps which are everywhere in my area a clanking noise is heard coming from the rear of the vehicle. I think it’s on the drivers side only, but not sure.

So far I’ve checked the following:
1- the bushings in the multi-links seem to all be intact. Car has no rust at all anywhere,
2-Makes noise if car is in neutral when I go over bump,
3-makes noise if car is in gear when I go over bump,
4-noise is not from spare tire or tools,
5-noise is not from rear windshield washer tank,
6-noise does not seem to be coming from a shock,
7-while exact location of noise is hard to pinpoint, it seem to be coming right from behind the tire, i.e., wheel,
8-condition of supporting joint at bottom of rear wheel carrier looks poor, see photo below,
9-Muffler and rest of exhaust system is not source of noise.

I’ve also attached a diagram of wheel carrier, the supporting joint is # 7a. The spring link is #6.

A photo of the supporting joint is also attached.

So does anyone have any idea what the source of the sound might be?

have you adjusted the parking brake shoes?

No I've not done that.

check ant. motor

I have the same issue with my 1988 TE as Ron does with his. I've had all of the things looked at that Ron has and I even looked at the antenna motor. None of it seemed to be the culprit.

If you have any success, Ron, please let us know.

Thanks.

I suspect it's the supporting joint, 7a which I discussed in my first post. It's also called the rear outer lower control arm bushing. That joint seems to function kind of as a ball joint in the rear. Hopefully someone that had this problem will view this thread and let us know. I'm sure I'm not the first person with this issue.

Edited

Here's a photo of the special tool to remove the supporting joint installed on the car.

Ron- had same problem on my 1989 300TE. Replaced the rear sway bar links and bushings and it solved my problem. Hope this helps. Jay

Other possibilities might be:
- the upper hydraulic strut mount (rubber settled, loose nut)
- lower strut mount worn (ball joint)
- subframe mount
Good luck, Bruno

Bruno,

I checked the rubber mounts and they are fine. The lower strut mount if I'm not mistaken is what my manuals refer to as the supporting joint.

I looked at the subframe mounts but I can not tell if they're ok, visably they look fine.

Ron
By lower strut mount I actually meant the foot of the strut that it is part of the strut itself. It is a ball joint that has some play on my car. The protecting rubber boot got damaged allowing water to enter so I asssume. The only cure seems a new strut (pricey).
Bruno

Bruno,

Below are two photos, the first is for orientation relative to where photo is taken. Second is of the part we are talking about, I think. The support joint bolts to the spring link after it is press into the wheel carrier. Does that make sense?

I did remove the torsion bar link (which is in fine shape) to check it and get a better view for photo.

Edited
That support joint/control arm bushing/ball joint is only about $30 each.

It occurred to me that you might be talking about what I would call a ball joint on the bottom of the hydropnematic shock.. Actually I had both shocks out to install new bump stops and new boots, both ball joints on the bottom of the shocks were in excellent condition.

Yes, I have been talking about those - sorry about the confusion.
I have been replacing the supporting joint 7a as well. It works well with the tool you have shown but do not try without it (do not ask how I know...).
I have read those can cause noise when worn but do no know from experience.
Good luck, Bruno

Below is photo of spring link separated from wheel carrier. Tension on coil spring was relieved slowly with a floor jack while vehicle was on lift.

Ron,
I was able to get the wheel carrier joint out with a combonation of stuff that I picked up from home depot. See picture...

Geoff,

I used your directions to remove the spring link with no problelm. Below is a photo of link and the coil spring after I wiped them down with simple green, they look quite good. I was going to replace the inner bushing on the spring link but it look and feels like new.

The support joint is another story. I'm not sure it's is the cause of the rear suspension noise, but I'm changing it because it look and feels worn out. See the photo of the supporting joint below, I cleaned it up and you can see what is essentially a ball type joint inside.

I may spring for the MB special tool or I may make one like yours. Did the joint come out easily with the tool you made? And were you able to seat the new joint with no damage to boot?

I did buy the special tool. It was expensive but it worked greated. Heated the part of the wheel carrier that holds the support joint with a heat gun and little bearing, bushing, ball joint or whatever it's called came right out.

Ron,
Buying the proper tool for is buying piece of mind. The tool (pic in earlier posting) that I put together worked well for me in all respects. But, I did have to go out and shop those pieces - and was never certain that it would work. Luckily, it did. It's an interesting make-or-buy analysis .

Glad things worked out - let us know if you get to the root of the noise.

Geoff

I installed the new joint supports and put everything back together and torque all fasteners to spec.

I did not think the joint supports were the source of the noise and I was correct.

I'm going to start a new thread as I can describe the sound exactly.

I think you should check the parking brake shoes.

Ron while you are under the car check your differential mounts to see if they are cracking. That could cause the type of noise you describe too I think.

Wiper motor? Just a thought.

also check the wheel hub bearing, it might need to be repacked (replacing or adding up new grease) or retighten, had that problem before on mine...

Mystery noise source identified and fixed.

Isolated noise to shock absorbers with my stethescope but still didn't know what was causing noise or how to fix it. So I took it to a friend who owns an MB shop in town for him to diagnosis. He had not heard a wagon making the sound mine was making when you bounced the rear up and down manually, without the problem being one of the ones I tested for.

He also thought it was the shocks so he manually filled and dumped the fluid from the control valve for the self leveling rear suspension with a couple of us sitting on the rear of the wagon with the tailgate open.

That fixed it. The problem was the shocks were not sufficiently full of hydraulic fluid. We don't know if the noise was air or what since the noise was present on both rebound and compression.

hello 104.992

Could you please indicate the dimensions of all the parts that make the tool you show in this thread?

I need to change the bushing of my car.

In advance many thanks

For whatever its worth, my 95 E320Coup and wagon both had a clunking from the FRONT passenger side, both turned out to be anti-sway bar and bushing as well... weird!

Ron,

Where is this support joint located ? On the rear hub/knuckle assembly or somewhere else ?

Do you have a pn# ?

:-) neil