When to replace shocks? - PeachParts Mercedes-Benz Forum

WannaWagon · #1 12-07-2004, 09:52 PM

Thinking about getting new Bilsteins for the front of my TD and was hoping you guys could help me justify it.

The car doesn't seem to bounce excessively, and it seems to pass the bumper-bouncing test. But man, does it lean a lot in the corners! I gotta hang onto that wheel or I'll be thrown out the window. Is this a sign that the shocks are going south, or is this how these cars always drive (only owned mine for 4-5 months)? Will new shocks help with this?

The car seems to have the OEM shocks on it still.

KCampbell · #2 12-07-2004, 10:18 PM

Body roll would suggest anti-sway bars not doing their job.

No shocks last 161,000 miles, so if you think they are original, replace them. My car didn't do badly on the bounce test, but rides much better with 4 new shocks. I don't put a lot of faith in the simple bounce test myself.

Kevin

psfred · #3 12-08-2004, 12:42 AM

Excess body roll usually means the links on the rear sway bar have parted company with the car. They have a viton insert that holds the bolt on, and when it goes bad, the link will fly off. MB sedans do NOT roll -- to the point, on the W115/4 chassis, you can push a tire off the rim under hard cornering!

Check the bushings on the swaybars (fornt are rear) as well. Check to make sure the sway bar end isn't broken off up front, this is a fairly common failure at high milage.

Bilsteins usually start to knock pretty badly when worn out -- the compensating piston (under nitrogen pressure) that keeps the oil compressed (and air out of the shock) will eventually hit the shock piston as it rises as the oil gradually leaks out. When they start to crash on bumps, replace. Usually no other symptoms.

New one will ride better than ones with 160,000+ miles, though....

Peter

braverichard · #4 12-08-2004, 01:03 AM

Both of Benzes still have their original shocks... the 300SD is currently at 157K. They both ride fine. Except the 300SD vibrates like hell at high speeds since I put the 16 inch wheels on it. I attribute this to the higher contact area between the road and the tires (went from 205/70/14s to 225/50/16s). In terms of work done by the shocks, the original shocks on my cars seem to be doing their jobs well. I once read from a forum member here that those Bilstein shocks take a really long time to wear out.

WannaWagon · #5 12-08-2004, 01:00 PM

Thx for the feedback. I'm not sure the collective wisdom here amounts to a "yes" or "no." But I have noticed some knocking lately from the front end when going over bumps. I'll also check out the rear swaybar bushings (I know the fronts are good).

Hatterasguy · #6 12-08-2004, 01:27 PM

How old are they? If they are original replace them they are shot.

#7 12-08-2004, 03:04 PM

Got quite an education on tires from a guy the other day at the Cosco tire store. Seems that often people "cheap-out" on tires, and cornering performance really suffers. My 300CD is rated to have a high speed rating...because of cornering, and "sticking" to the road.

Just a thought.

Joe

psfred · #8 12-08-2004, 08:12 PM

Vibration at speed isn't contact patch, it's an out of round tire, an unbalanced tire, or a bent rim.

Get a good balancing job done, and let them put weights on the outside, too -- the "slight" imbalance required to avoid outside edge balancing weights will knock your teeth out at 80 mph!

Note that all tires are NOT round, and that a hard spot in rotation due to interal dissarangments in the tire can also cause serious vibration.

Peter

#9 12-08-2004, 08:27 PM

If you have the origional shocks, change them along with looking at your sway bar and most likely the front end suspension is needing a over haul. I'd suspect your lower ball joints and upper control arms are bad. I just went through this expereince about 3 months ago. What a difference the ride makes now. It'll cost you unless you can DIY.

braverichard · #10 12-09-2004, 01:14 AM

Quote:

Originally Posted by psfred

Vibration at speed isn't contact patch, it's an out of round tire, an unbalanced tire, or a bent rim.

Get a good balancing job done, and let them put weights on the outside, too -- the "slight" imbalance required to avoid outside edge balancing weights will knock your teeth out at 80 mph!

Note that all tires are NOT round, and that a hard spot in rotation due to interal dissarangments in the tire can also cause serious vibration.

Peter

I purchased the rims (which were used) and brand new tires. They mounted them on and balanced them. Then they did a four wheel alignment. On silky smooth highways the vibrations aren't that bad, but on most highways 80mph can't even be done the in car without a whole lot of vibrations. City driving is smooth with no problems. So, what do you suggest I tell them at the tire place?

#11 12-09-2004, 09:08 AM

I'm sorry for going against the conventional wisdom here, but if the shocks are original, then they are quality units and could very well be in good shape after a few hundred thousand miles. Just because they have high mileage does NOT mean they are gone.

It depends on road conditions that they have lived with. If they are aftermarket and not Bilstien, then they very well could be shot. As psfred said, they are worn out when they are loose and knocking. I've seen Bilstiens with almost 300,000 miles in such good shape that you couldn't tell the difference after replacing them.

On the 123 the shocks are very easy to replace, so I would loosen one end and give them a shove. If they are not rattling and still have pressure, leave them alone.

My $0.02,

oldnavy · #12 12-09-2004, 09:42 AM

I replaced the shocks on the 240D because they were orignal to car and the difference was quite noticable. I did the bumper bounce and it passed, but one shock looked like it had had some fluid leaking in the past.

Anyway when they were pulled off, the old ones were what I would call strong if they had been a cheap shock, but nothig like the new Bilstien I installed. On the old ones I removed from the car the buffer material on the shaft had detererated and most of the stuff was gone.

#13 12-09-2004, 06:44 PM

Quote:

Originally Posted by psfred

MB sedans do NOT roll -- to the point, on the W115/4 chassis, you can push a tire off the rim under hard cornering!

There was a thread on here somewhere talking about how all benzes apart from the w115/4 were desigend to have some body roll to address this issue that creeped up on them.
Instead of popping tires off the beads, they decided to have the cars roll a bit.
It would be safe to say that MB sedans are supposed to roll, not remain extremely firm and 'biff' it.

I am not sure where the thread was...I think it was a 300SD handling thread...I will see if I can find if for ya.

Brandon

psfred · #14 12-09-2004, 07:29 PM

Tell them they need to verify that the rims are indeed round and have no runout, and that the tires have been mounted correctly so that they have exactly the same diameter all the way around. A piece of chalk run just barely touching the tire on the balancing machine will tell you. If the tire isn't perfectly round, the chalk will not mark it all the way around (a paint marker works well too). Takes a light touch, but if there is a bulge or out of round condition, the tire will vibrate at high speed.

A bad belt, or a hard spot in the tire, where it flexes less, will also do this.

You should also attempt to determine where the vibration is (right/left, front/rear), and have them move the tires around to see if the vibration follows the tire. If so, I'd insist on another tire or pair of tires, they are either defective or improperly balanced. I suspect you must have a dynamic balance done on a good machine, the simple more or less static balance won't work.

If they are not V rated tires, swap them for some that are.

Peter

braverichard · #15 01-05-2005, 09:58 PM

Unfortunately for me Peter, you were right!

Before I took the car to the tire place, I rotated the tires from the vibrating end to another end and it just got worse! To be exact, the vibration comes mostly from the front passenger's side, so I rotated the two tires on that side of the car. After it worsened, I took the car to the tire place. They pulled all four wheels and determined that I had one really bent rim and another slightly bent rim. In fact, the rim that was really bent was the one that ended up in the front passenger's side after I did that rotation.

I then had to pull all four wheels, put back the original M-B wheels and had my luxury car ride restored. How those rims were bent is something I don't get. I was beginning to think I had suspension issues when it was all in the rims. And to think I paid so much money for these! This is the first time I've ever purchased used rims and it will definitely be my last.

Anyway, I have two questions:

1) Is there any facility that straightens out bent rims, or is my luck really that bad in this deal? The guy that determined the rims were bent told me that he doesn't know of any place that fixes such rims.
2) The rims in question are 16" Lorinser chrome plated rims. Do you know if these are still being sold, brand new from the manufacturer? I'm checking on this in case I have to purchase replacements. Well, actually, I'm probably better off posting this question in the wheels section.

Thanks for your help Peter. Too bad for me you were right, but I'm better off having a solution to this problem. Also, sacrificing the look of my car in order to get back the smooth ride isn't so bad now actually.

Why make the car look so nice for everyone to look at it when I don't even enjoy driving it?