During the course of upgrading the handling of my C280 I have picked up a rattle when the car goes over small, little ripples and bumps.

I sounds like the shock is loose, kind of like the bolt would be rattling in the lower control arm.

But as far as I can tell the bolts holding the shocks and swaybars are tight.

Are there any other suspension pieces that could make this kind of sound. The subframe, control arms, ?

Jeff

Take a Close Look at the Front sway bar Brackets..they Break!
Also Inspect the lower Control arm Bushings..They Can Make the Noise you are Talking about..
Good Luck!

Thanks Mark,

I guess I should have made it clear that the noise is coming from the rear only.

Once the suspension is under a load the noise is gone. I would guess because the slack is then taken up.

It's like I have a 6mm bolt in an 8mm hole, if that helps to get a feel for the type of sound.

Jeff

Had the same problem with '87 260E. The problem was caused by broken E brake shoes at the rear. Lift car and shake tires L & R. Hope this helps... not sure if it would apply to your model/year....

Nice suggestion,

I will look tonight and see if they are broken.

How were the Ebrake shoes broken? Was it them or the mechinism?

Thanks,

Jeff

It was the pad's lining (1/2 of 1 shoe) that was detached from the shoe. My mechanic said that this happens when either you forget to release the brake before driving off and/or when they get too old. In my case, both since my car has been in the garage most of it's life (51K mi original) on 87 260E.

Hope this helps....

Well, I removed the left rear disc brake rotor and the parking brake pads are in good shape an undamaged.

Then I thought it might be the upper rear shock mounts because the rubber isolators sit in that metal cup and the shock is attached with a big flat washer that is slightly larger then the metal cup. So I thought that the flat washer was hitting the metal cup on the small, ripple type bumps causing the knocking noise. So I added another rubber washer to space the to metal pieces apart.

Drove the car and the noise is still there.

When I had the wheel off I pushed and pulled and tapped on every part, contol arm, etc. and could not reproduce the same rattle and knocking noise.

Very fustrating.

Jeff

Where EXACTLY is the sound coming from?

I had a similiar sound and I quite sure it was from the rear left door panel (or in the door) or n the B-pillar. So sure, that I removed both of those panels and had my wife drive me around while I listened. No go, it still rattled over little bumps -- almost a knocking sound. "Tock, tock, tock"

Thought it was a door hinge, so drove with doors open, windows down --- you name it. Still sounded like it was coming from the B pillar or front portion of rear door.

Finally, I removed the left rear wheel to check the pads etc. Everything looked good. While it was on a jack stand, I tightened the 2 smaller hex bolts for the support plates on the frame floor (as the shop manual describes it).

Put the wheel back on, and now the sound is gone!

I am sorry I dont know where those two hex bolts are located.

Can you describe further

Thanks

jeff

They are located just forward of the rear wheel, set up in circular fashion. My wife has the car right now, otherwise I'd take a quick digi-pic for you. The center one is larger than the other hex bolts which I *barely* tightened.

Not sure if this is the case with your C280 as I'm not too familiar with them. It's worth taking a look. It almost looks like a metal pad for the jack.... you'll see it if you have it.

Are they in the wheel well or on the bottom of the frame rail around the rubber jack button?

However the noise you describe sounds just like what I hear.

Jeff

Yup, the frame rail -- jack pad -- tho' I don't use my floor jack there as it'll tear it up. My guess is that when my buddy and I did the brakes on it a before the rattling started, he used it as a jack point and forgot to use the piece of wood we had on hand...

Thanks a bunch. I will go check that out right now.

Jeff

Well I found the source of the knocking noise. It was the spearical bearing at the top of Penske shock that is on my car.

I found out it was moving up and down about 0.008". Just enough to cause the bolt and bearing to rattle up and down and cause a very irritating noise.

I was able to shim up the bearing and that got rid of the noise.

I am soooo relieved to find that dammed noise.

Thanks for all the help everyone.

Jeff

I think I found and fixed the noise. It turned out to be a worn out or loose spherical bearing in the top eye of my Penske shock.

For now I just shimmed the bearing to get rid of the play. And that has eliminated the noise.

Thanks you all for ideas and suggestions.

Jeff