bouncing, bouncing, bouncing, keep those dogies bouncing... - PeachParts Mercedes-Benz Forum

#1 11-24-2002, 04:40 AM

Minor complaint but worth bringing up for discussion: the ride on my 300TD with the self-levelling rear suspension is quite, well, bouncy.
Especially on worn or uneven roads. It's not harsh, it's just like we're going up and down ALOT. It's almost nauseating.
It handles fine otherwise, handles bumps fine, and on smooth road it's like glass.
I know that the self-levelling suspension is working well. Will replacing the front shocks help with this or is it just something to live with?
Is there any technical assistance posted on the forum anywhere in regards to replacing front shocks?
Thanks.

MikeTangas · #2 11-24-2002, 10:38 AM

I assume the bounce is from the rear? If so then the self leveling isn't working as perfect as you thought. The SLS may rise and fall in the presence or absence of a load, but that bouncey, bouncey says the nitro cells need to be replaced.

rickjordan · #3 11-24-2002, 11:04 AM

I can help you on both accounts, I have replaced both the rear nitro cells and front shocks on my TD. For me most of the bouncy ride was caused by the bad shocks. When I removed the shocks, I found that they were the ORIGINAL shocks from 1983. However they were completely shot. I was able to push the rod in by hand, without much effort. First do not skimp on shocks, these cars are very heavy and will require a serious shock. Stick will Bilsteins, Mercedes has for the last 40+ years. This is what I did. With the car on the ground, loosen the nuts on top of the shock. Now, jack the car up, remove the wheel, and start removing the 2 bolts holding the shock to the spindle. These are 12 point, 10mm bolts. Installation is in reverse order. Do this first and see if this illiminates or reduces your bouncy ride. The rear nitro cells are more expensive than the shocks. Does the rear of the car sag at all after it's been sitting for a while? The design of the car makes the backend look like it's sagging so to be sure the backend is at the correct height,do the following. Take a ruler and measure the distance from the jackpoint hole to the ground at all four corners. Of course make sure the cargo area doesn't have anything in it. They all should be about the same, give or take a little. If the back end is indeed sagging, check to see if the rear hydro-pneumatic shocks aren't leaking ($$$$$). If they are dry, then your nitro cells are bad. To replace these, you will of course need 2 new cells, one for each side, and replacement hydraulic fluid. You will also need a 11mm flarenut wrench. Do the front shocks first, and if that doesn't fix your problem, post what you find on the backend and I'll tell you how to replace the rear nitro cells.
I replaced mine due to the sagging.

rickjordan · #4 11-24-2002, 11:07 AM

One other thing you might want to do, buy yourself a Haynes manual for the W123 chassis. These cost about $15 at any autoparts store. This will help you alot. These books have excellent photos in them.

psfred · #5 11-24-2002, 02:32 PM

Bounce the rear of the car by stepping on the bumper -- if only the tires move, not the suspension, or it is VERY hard, you need new accumulators. Not a bad fix -- get the new accumulators and a quart of hydraulic fluid (use ONLY the MB stuff, anything else will cause you much more expensive repairs....).

Put the rear of the car up on jack stands for acesses, then clean the connections for the hydraulic lines, removing lines, remove accumulators, catch the dripping oil, install new accumulators, re-install hydraulic lines, and refill the fluid reservior.

On the W123, the accumulators are under the rear passenger floor, accessable from under the car.

Peter

Peyton300TD · #6 11-25-2002, 10:44 AM

same exact problem on my TD. my sister said it was like riding a roller coaster.

the problem was fixed with new nitrogen air cells and ran me about $500 parts and labor.

it's worth it though to avoid the nausea.

eric

rickjordan · #7 11-25-2002, 08:06 PM

If you change the cells yourself it will cost you alot less than $500. I got my cells for $75 a piece and the fluid was something like $7 a liter, you will need about 3-4, can't remember.

psfred · #8 11-25-2002, 08:08 PM

It can get actually dangerous to drive the car, since the rear tires will bounce so badly they aren't on the ground half the time. I got a pretty good "discount" on the TE by claiming it wasn't drivable with bad accumulators. I should feel bad, but don't!

Peter

#9 06-24-2003, 12:40 AM

I replaced the front shocks and that seemed to help but now on a business trip down to Chi-town we were bounced silly!

I know it's the back end because I've gone back there both with the car off and idling and it seems I can really get the car rocking pretty easily by just pushing on it with my hands, no jumping on the bumper required.

I know the SLS is working after taking ground-to-body measurements before and after starting the car.

So...bad nitrogen cells? Am I just bouncing up and down on the springs like another post seemed to indicate?
-shawnster

Dinosaur · #10 06-24-2003, 08:39 AM

I also have the bouncy rear end. I replaced the front shocks with bilstein comforts. That didn't seem to help. I bought rear accumulators and replaced the as well. My car still bounces. I made the mistake of raising the rear end slightly by changing the leveling valve on the rear sway bar. I think this may cause my bouncing problem.

How does one measure the correct ride height at the rear?

Also my rear end sags still after the car has been setting for a day. I'm thinking that the rear leveling valve needs rebuilt.

Shawnster, I read your posts on your leaking from the front windshield area.
I just posted on a problem like that. See the post ( Leaking may not be due to windshield gasket)

Mike

pkmorgan17 · #11 06-24-2003, 10:21 AM

Don't worry if it sags after sitting for a day - the only concern is if it doesn't raise after car running for a minute or two.

jassz · #12 06-24-2003, 11:49 PM

Yours was the clearest, most concise description of how to remove the front shocks! I did a search here, but the opinions as to how to do it seemed to vary, and the cd manual goes on for days and is not very clear (and it can be a dangerous job!). You said it all in one paragraph, and even said exactly what size wrench is needed! Unfortunately we don't have it (yet).

I have a tentative appt set up with our mechanic to go over a few things next Monday, but if things keep progressing the way they have we may not need her (largely thanks to this board!). We have already removed the self leveling strut from the parts car (Belinda's was leaking) and plan to scalp the front shocks as well. There is far less bounce to the parts car when you push down in the corner, so I think they're pretty good.. We also scalped the strut used to hold the rear hatch up... yeah! There is a number on the strut, and I think part of it denotes a date. If so, the one from the parts car was made in 1998. The original one in Belinda wasn't dated, but it said, "Made in West Germany". When was Germany unified? 1989 or so wasn't it? Anyway, with the 'new' one installed it's like the car got a dose of Viagra.

dmorrison · #13 06-25-2003, 12:03 AM

The one consideration on removing and replacing shocks it to prevent the shaft at the top of the shock from rotating or you may allow the shock to release and cause injury. To prevent this you hold the shaft. It usually has a flattened section for a wrench or a slot for a screwdriver, and then you rotate the nut below it. Sometimes when you rotate the nut. The shaft turns and you may screw the shock assemble apart and it will release a lot of gas pressure ane force.
This post covered the process.

http://www.peachparts.com/shopforum/showthread.php?threadid=60880&highlight=shock+tool

Dave