Renntech suspension work

[Trae]

Well, It was May of 2013 when I took my Renntech to Jono.
He did a lot of front end work, but did not have time to address the rear suspension before Startech.

Jono sold me two hydro shocks that I intend to install with new spheres later this month. I have not been diligent to take pictures of the jobs I have been doing,but I hope to change that with my wife's new digital camera.

The Renntech has the dreaded "cathunk" sound when going over bumps and does not feel as tight as my 93'. Hopefully, this will correct that.

Chime in if you have any advise on this job (ie. . .links). It will be my first attempt.

 

[gsxr]

FSM procedure, with diagrams:
http://www.w124-zone.com/downloads/MB CD/W124/w124CD2/Program/Chassis/32-0610.pdf


Note that the first step is to de-pressurize the system:
http://www.w124-zone.com/downloads/MB CD/W124/w124CD2/Program/Chassis/32-0630.pdf

 

[rol607]

My '94 was experiencing the same "cathunk" you describe. Per Dave, I switched out spheres and both rear shocks. All is great now!

 

[Trae]

I was going to replace the rear sub frame bushings to see if that would help, but I'll try this first and save the bushing job for later.

 

[gsxr]

Rear sub frame bushings usually won't cause clunking noises, unless they're really, really bad, and I've never seen any in that condition (yet).

Differential mount bushings can cause clunking when worn, but that is common on the 6-cyl diff mounts, which are smaller. The V8 diff mounts are massive and I've never seen any wear badly enough to cause clunking (yet).

 

[Trae]

Update:
After changing the accumulators and new hydro struts (thanks Jono), the car drives like new!
I was going to try this work myself with the help of this site, but my indy mechanic was better equipped for the job and only charged me 3 hours labor.

The lower bushings were totally disintegrated. I think that was the main reason for the "cathunking" sound when going over bumps.
Also, the old accumulators were failing and gave a very bumpy/harsh ride.

 

[Stevester 500E]

GSXR, so clunking is usually the accumulators correct? What is the best price out on the web for new hydro struts?

 

[Trae]

I bought struts from Jono, however, Fred may still have these for sale:
I am not certain that they are the same struts, so do your homework.
I bought metal oil tubes from Fred and was very happy with his service.

SLS rear shocks

If you are still looking for SLS rear shocks
i have a set of shocks from a 600SL, the V12 convertible.

I sold several sets of these for people that own 500E, i used a set on my 500E which i sold and all is good, they fit fine and none of my buyers had any issues with them.

Part numbers:
sachs 01 2400 102 321
mb 129 320 11 13

if you're interested, $300 shipped for both

here are pictures:
http://www.furi-dorifto.com/sale/mer...0e/suspension/
​

 

[sheward]

Glad to hear you have the Renntech riding smooth, Trae!

drew

 

[gsxr]

GSXR, so clunking is usually the accumulators correct? What is the best price out on the web for new hydro struts?

Clunking is usually the shocks, not the accumulators. Best price will be from parts.com but even there the shocks are ~$800/pair. There seems to be two failure modes on the shocks with the clunk... either the lower eyelet bushing disintegrates, or something fails internally that causes the noise. I've heard of both.

Accumulators cause a rock-hard ride but not clunking.

The set of shocks Fred has are from an R129 and they are not the same as the 500E shocks, however I don't know the exact differences. They may bolt up but there could be differences in travel, valving, etc.

Trae, can you post photos of the "lower bushings totally disintegrated"??

BTW... there is no method I'm aware of to bench-test an SLS shock for the clunking, if the lower bushing is ok. You gotta install used ones and drive on them to see if they make noise.

 

[bing]

Don’t the upper bushings on the struts cause clunking as well due to age and as they get compressed? Also, I take it the lower bushings cannot be replaced separately, meaning if these are knackered you need new struts ?

 

[gsxr]

Don’t the upper bushings on the struts cause clunking as well due to age and as they get compressed? Also, I take it the lower bushings cannot be replaced separately, meaning if these are knackered you need new struts ?

I've never heard a confirmed case where worn upper bushings caused a clunking noise, but the rubber does wear with age and it doesn't hurt to replace them.

I believe the lower bushings are actually a spherical joint similar to the wheel carrier support joint, and no, they are not available separately. Some folks were looking into aftermarket replacements to salvage otherwise-good SLS shocks but I've never heard of a successful retrofit. It's usually cheaper and easier to just replace the darn things and they'll be good for another 20+ years...

 

[Trae]

Yes, I will try to post the lower bushing pictures.

I replaced the upper strut bushings first about three months ago. I was hoping that was the problem, but it was the struts themselves making the clunking noise.

The accumulators were delivering a very harsh ride. Something like riding on a brick, so I also had those replaced at the same time.

 

[Glen]

Trae, can you post photos of the "lower bushings totally disintegrated"??

Dave, here's a couple pictures of one of the struts that came out of my 199 car.

The joint is so loose that the lower part of the mount has worn away from rubbing against the LCA.

 

[Glen]

Here's a quick video I shot...see how loose the joint it?

[video=youtube;bnch3OMgWpM]http://www.youtube.com/watch?v=bnch3OMgWpM[/video]

 

[gsxr]

WOW! Great photos & video, Glen. I've never seen anything that bad. And the bottom end of the shock is flattened out from rubbing the bottom of the LCA? Yikes. This would definitely cause a nice rattle/clunk noise.

 

[KarlC]

So do you have to replace the whole strut or can you just replace the bushings then its this bad ?

And is that what usually goes bad is the bushings ??

 

[Trae]

As far as I know, you have to replace the strut.
You cannot replace the lower bushings.

 

[gsxr]

As far as I know, you have to replace the strut.
You cannot replace the lower bushings.

Trae is correct. I think the clunking noise is 50/50, half the time it's the lower bushing as in Glen's photo+video, the other half the time it's internal and basically invisible.

 

[gerryvz]

There's no real easy fix when it comes to the rear hydro legs. They have to be replaced when they clunk (at least, when it gets pretty bad over bumps) and there's only one source for them..... MB OE part.

Best to replace the pair, and best to buy them through parts.com. Unfortunately this is one situation where MB has all of us by the balls. The only other option is to buy used, but even then (unless they are known low miles) you don't totally know what you are getting.

The one bright spot is that the rear hydro legs don't wear out very often, so when you replace them with new factory units, you should be good for another 20 years....

Cheers,
Gerry

 

[jhodg5ck]

this is the bushing I want to find a replacement for...far too many of these rams are going bad when it's only the damn bushing that's worn. Lame.

 

[gerryvz]

this is the bushing I want to find a replacement for...far too many of these rams are going bad when it's only the damn bushing that's worn. Lame.

Sounds like an excellent project for ..... Jackasic

 

[8899]

An admin may want to merge this thread with this one here:

http://www.500eboard.com/forums/showthread.php?t=5556

 

[samiam44]

Jono,

Just need the OD for the bushing, and ID for the rubber.. I'm sure I can match up something.


Michael