Mystery mount disintegration - PeachParts Mercedes-Benz Forum

ck42 · #1 08-02-2014, 03:08 PM

So, first question is: What mount is this?
Second, why has it disintegrated like this??

This is on the driver's side, picture taken from the rear side of the tire.

uberwasser · #2 08-02-2014, 03:22 PM

This is your 300SD? Looking like a control arm bushing but I'm not that familiar with the W126's. Someone will know for sure.

Regarding the why, that looks chemical breakdown. Something was leaking on it, weakening the rubber. It looks sort of how my driver's side motor mount looked when I had biodiesel leaking on it - biodiesel is very aggressive on rubber. Here is a picture of the tank neck seal on the same care - I never let bio drip on that seal anymore.

ck42 · #3 08-02-2014, 03:47 PM

Funny you mention the driver's side motor mount. I had changed both mounts not all that long ago. While do a bunch of work recently, I found that that motor mount was also disintegrating. the right side one still looked perfectly fine!
I've never run bio-diesel...and can't think of what might have dripped onto BOTH of these mounts to cause this.

vstech · #4 08-02-2014, 03:51 PM

I believe that is the guide rod subframe mount, I've never seen one like that though...

vstech · #5 08-02-2014, 03:53 PM

Could be this
Stupid iPad won't let me select the part... It's the support arm to subframe bushing

ck42 · #6 08-02-2014, 04:01 PM

Just verified, it's this: (#113)

What's weird is that I found another thread where someone had what looked like an identical situation where the same bushing (#113) was rotted and the other one was just really worn and squishy looking.

So, next question: This bushing hard to replace? I had the guide rod mounts themselves replaced a couple years ago, so that stuff should not be seized or hard to undo.
Guessing these bushings need to be pressed out and back in?

What's involved with getting that whole 'L' shaped arm off the car though?

ck42 · #7 08-02-2014, 04:19 PM

Are both of the bushings on the carrier the same part # ?

vstech · #8 08-02-2014, 04:22 PM

Can you post a better pic of the part diagram...

uberwasser · #9 08-02-2014, 04:45 PM

Quote:

Originally Posted by ck42

Funny you mention the driver's side motor mount. I had changed both mounts not all that long ago. While do a bunch of work recently, I found that that motor mount was also disintegrating. the right side one still looked perfectly fine!
I've never run bio-diesel...and can't think of what might have dripped onto BOTH of these mounts to cause this.

I didn't realize both sides were like that, so yes, no likely to be that after all.

Were they URO brand???

ck42 · #10 08-02-2014, 04:46 PM

It's #16 here. The fact that it's showing both bushings as #16 seems to indicate that they're the same part...

DrLou · #11 08-02-2014, 06:15 PM

ck42,

Do yourself a favor while you have those subframes out, and replace the brake reaction bushings as well. I did this job many years ago. Yeah, it was pretty heavy, but managed it with hand tools.

I did have the bushings pressed out by the local shop, but am sure any of us here could handle this with some creative toolmaking.

Have you found the source of that disintegration? On that side, you could have fuel implicated, power steering fluid...

ck42 · #12 08-02-2014, 09:15 PM

If by 'brake reaction bushings' you mean the Bearing Bracket guide rod mounts, then as I mentioned, I already had those replace a couple years ago.
Haven't figured out yet if there's a leak of some fluid causing this, but power steering fluid is something to consider. Should be easy enough to locate though if that's what is causing it.