Repair the little belt tensioner shock absorber?

[S-Class Guru]

You know, the tiny shock absorber on the 103 belt tensioner.
These cost $35.
Seems the only fail mode is when they start to rattle because the rubber bushing in the end of the shaft shrinks and gets loose.
I'm about to have to buy my 3rd one, and the first two are fine except for the rubber bushings.
I tried deforming the eyelet, and putting an o-ring between the bushing and the mounting washer. these worked for awhile, but the rattle returned.

Anybody found something suitable to replace the tired rubber bushing?

tks,
DG

[dkveuro]

Are you sure the stud bolt is compressing the center spacer and not staying loose.

I have installed many of these over the years and can't ever remember replacing one earlier than a few years later.

Of course, all mine where MB OE. What do you have?

My own 300e has one over 5 years old...no rattles, but there again, I run with no plastic viscous fan.


.

[TMAllison]

On my E300 diesel, I went through 3 dampers before discovering partially collapsed motor mounts were the root cause.

Your tensioner is subtly different than my setup but is easy to check the condition of the mounts to rule that out.

[Arthur Dalton]

The trick with the O ring is to put it on/around the shaft/pin that goes through the eyelet, not on the side of the pin....that takes up the slack of the bushing while still allowing full tightening of the pin bolt. When all together , you will then see the bushing can not move sideways b/c it is now sandwiched between the O ring and washer..you can use one on each side.
I have done this to many and they have lasted for years.
Correct way is supposedly a new shock, but O ring trick does work if done right...[ not that you have not done it correctly] and seems to be better than a new shock b/c the new shock seems to have the same fail rate as the old one did....

[S-Class Guru]

Thanks guys. Arthur, yes, I was using a similar technique; the center bushing will pull up quite tight using the bolt, so that is not the problem. The problem is that the rubber doughnut in the shock eyelet shrinks after several years, and allows the eyelet/shock to move up and down and thump. You can really feel it on the top of the eyelet with the engine idling. Placing an 0-ring between the bolt washer and the doughnut, concentric with the worn-out doughnut/bushing kinda spreads the doughnut out, but eventually loosens up.
I think some kind of new rubber doughnut for the shock would be the best solution. Oh well, a new shock every 8 years ain't so bad.

DG

[Arthur Dalton]

Yeah, the O ring trick is only a solution for lateral play..which most have b/c the glue that holds the bushing to the eye dries up, allowing side rattle....
I am sure you could take the damper off and use almost any good rubber inserted in there of proper size and over-cut to length... over-cut on the length would make the rubber tighten on the pin when reassembing...

Look around at some other old parts that use rubber bushes..

[lee polowczuk]

I think when this happened to me, i got a couple of washers to make up the space difference