Violent front end shaking/55+ MPH/'82 300SD - PeachParts Mercedes-Benz Forum

rocketman93116 · #1 09-18-2006, 03:46 AM

Violent front end shaking/55+ MPH /'82 300SD/201,000 miles. I suspected worn front shocks. I installed "known good" - by MBZ mech - used front bilstein shocks(removed KYB shocks). Lifted front of vehicle by frame cross member, checked play front to back, side to side on both left and right wheels, feels OK. Have not done anything else to front end, except visual, as of yet. Any ideas?

I'm open to suggestions, thanks guys.

PatricdeBoer · #2 09-18-2006, 04:06 AM

There are a couple of threads around on this subject, but I had the same thing in my 81 300sd. It was a violent shudder that would develop into almost a pounding if you kept going. I think the general concensus on the cause was general looseness in the front end, namely the lower control arm bushing, and the track rod mount. I replaced my wheel bearings, shocks, and tie rods since then, and the shudder only comes back on certain road surfaces, so it'll take a full rebuild to get rid of it totally.

mplafleur · #3 09-18-2006, 08:21 AM

New tires fixed mine. Nice smooth ride this morning.

This was after all new front end components and an alignment.

I verified this first by rotating them. The shaking moved to the rear.

rhodes2010 · #4 09-18-2006, 11:36 AM

Did this new problem came on all of a sudden or gradually ?

In my case it was out of round tires.

Out of balance can produce same thing.

OMEGAMAN · #5 09-18-2006, 11:52 AM

I vote for tire balance. Check that first it's cheap and easy.

rocketman93116 · #6 09-18-2006, 02:39 PM

Had the car about 6 mos. Only did it a few times on freeway at 65-70 mph. Problem Seems to have gotten worse(more sensitive) after installing shocks this weekend. Did it last night once on road test. This morning on way to work(35 mile drive-all freeway) I can sense when it is about to start the convulsing vibrating shakes, it will start shaking the front end a little then progressively gets worse very fast. I back off the accelerator at those times when it just starts and it simmers down. It will seem to start just after 55. Tried to keep it at 55 or less this morning.

I am going to closely check front end. Will check with prybar method where warranted and putting a wrench on all bolts and nuts just to make sure they are tight. Going to jack up front end tonight and do all that along with a very close visual. I washed the under carriage, suspension, engine(again)last night.

I will switch tires either way(thank you), see what happens. I can't afford to rebuild the front end. Even with free labor.

Did research since original post. Used the word "shake" for search. Lot of results. Shake rattle and roll man, Love these cars. I did a few other things over the weekend that I will document document later for that post. But I can't afford to go off on a tangent right now. I need to focus on this front end vibration like a frickin star wars laser beam.

Brian Carlton · #7 09-18-2006, 02:46 PM

The SD has a bit of a shimmy on left handed curves at 65 mph or so.

It's been getting worse and a thorough check of the steering produced nothing. I'm leaning toward the upper ball joints and the LCA bushings which appear to be original. The lower ball joints seem to be in good shape and have been replaced somewhere along the way.

I would doubt that the guide rod bushings would cause this unless they are really trashed and you'd notice that on braking.

rocketman93116 · #8 09-18-2006, 02:56 PM

Brian, I would tend to agree that it would not be guide rod bushings(even though the rubbers are cracked), or the rod mounts(boots/rubber gone) for that matter as that seems to only cause the "clunking" from stop and go/ over bumps at low speed which have been described through out the forum here(forward and rearward movement for the most part).

Going to look at LCA's and b/j's also(thanks).

I will be replacing those eventually, but first things first on this little project.

Brian Carlton · #9 09-18-2006, 03:15 PM

If I ever see my compressor again, I'll also do LCA bushings and UCA's. Probably tie it in with front brakes and then see how she does.

rocketman93116 · #10 09-18-2006, 03:46 PM

I have a cambell hausfield upright, but last time I plugged it in to the apartment garage outlet it tripped the circuit breaker for the whole row of garages- and they all have automatic garage doors openers. OOPS!

Mr. Rogers - singing in my head "Oh, won't you be my neighbor"

BOMC · #11 09-18-2006, 09:29 PM

id look into warped rotors all around, i spent two years sniffing for a shimmy and after i did everything on the rear brakes in june (had everything done on the front ones previously) it went away.

for my problem, i had a bad shimmy that would get progressively worse say 40-65 but after 65 sorta went away a little bit. it noticed the issue was worse with more of a load in the car

. to this i also had pulsating (not ABS) sensations in the brake pedal while braking that was rapid at high speeds and slower at lesser speeds.

barry123400 · #12 09-19-2006, 05:38 PM

Rotate the front tires to the back on the same side. Also make sure you do not have a really loose front wheel bearing. Best test for the wheel bearing is to pull back and push the top of the wheel in and out and listen. Each side should be about equal. Deal with any abnormal clunk. Ocasionally someone previous did not seat the bearing races and they get pushed in after awhile creating too much bearing play. Both above easy, quick and cheap to check.

OMEGAMAN · #13 09-19-2006, 09:59 PM

I once had a customer with a 95 Range Rover 4.0 . It had a bad shimmy that I could not figure out, it had no problems in the front end so on advice from another mechanic I replaced the steering shock on the front axle. This did not help. On advce from the same mechanic I replaced it again with another new one and the problem was solved.
This thing had a terrible shimmy. I never would have guessed that was the problem especially after the first steering shock replacement.

rocketman93116 · #14 09-20-2006, 12:09 AM

Quote:

Originally Posted by OMEGAMAN

I once had a customer with a 95 Range Rover 4.0 . It had a bad shimmy that I could not figure out, it had no problems in the front end so on advice from another mechanic I replaced the steering shock on the front axle. This did not help. On advice from the same mechanic I replaced it again with another new one and the problem was solved.
This thing had a terrible shimmy. I never would have guessed that was the problem especially after the first steering shock replacement.

Thank you.

Question: Wouldn't I feel the steering wheel shake if the steering shock or dampener was bad? In addition, wouldn't other faulty steering components also cause steering wheel shake? I don't known these cars very well, pattern of failures. What fixes what. I'm on a learning curve here with working on these MBZ. It sure would be nice to have a known good steering shock to try out.

When the shaking occurs the whole front of the cars shakes hard, but the steering wheel only shakes slightly.

My plan for this weekend is(funny how these weekend projects spill over in the following week, what the heck I'm having fun,sort of):

1. Switch tires front to back and see if the problem moves with the tires.

2. Check and inspect wheel bearings/clamp nuts for loosness.

3. Install "zerk" or grease fitting on pitman arm and lubricate. Somebody previously installed the part and did not lubricate it. It is causing a groaning noise when turning steering. I found this while doing visual inspection and checking front end monday night.

When I hit the lotto

I will starting throwing parts at it, metaphorically speaking of course......

Did not find any thing that would explain the shaking, yet.

By the way, thanks guys for the tips and suggestions, wish I was working in a shop again. Sure would be nice to have a hoist and air.

OMEGAMAN · #15 09-20-2006, 10:44 AM

Quote:

Originally Posted by rocketman93116

Thank you.

Question: Wouldn't I feel the steering wheel shake if the steering shock or dampener was bad? In addition, wouldn't other faulty steering components also cause steering wheel shake? I don't known these cars very well, pattern of failures. What fixes what. I'm on a learning curve here with working on these MBZ. It sure would be nice to have a known good steering shock to try out.

When the shaking occurs the whole front of the cars shakes hard, but the steering wheel only shakes slightly.

My plan for this weekend is(funny how these weekend projects spill over in the following week, what the heck I'm having fun,sort of):

1. Switch tires front to back and see if the problem moves with the tires.

2. Check and inspect wheel bearings/clamp nuts for loosness.

3. Install "zerk" or grease fitting on pitman arm and lubricate. Somebody previously installed the part and did not lubricate it. It is causing a groaning noise when turning steering. I found this while doing visual inspection and checking front end monday night.

When I hit the lotto

I will starting throwing parts at it, metaphorically speaking of course......

Did not find any thing that would explain the shaking, yet.

By the way, thanks guys for the tips and suggestions, wish I was working in a shop again. Sure would be nice to have a hoist and air.

On the Range Rover I wrote about the steering wheel didnt shake too bad it was the whole front end of the truck that shook. On the test drives I went on people noticed what was happening in traffic.
This thing drove just like any of the other Rovers I had driven until it started to shake. Maybe you can find a steering shock in a junkyard and give it a try. Or borrow one from a friends car so you don't have to throw money at the problem.