Just Replaced Driveshaft Support Bearing & Rubber Mount - PeachParts Mercedes-Benz Forum

ajb · #1 08-09-2002, 01:50 PM

Hi Folks,

I just replaced my driveshaft support bearing and rubber mount on my 240d \4spd trans - and what a difference. The rubber mount had suddenly ripped and was causing a vibration at low speeds. So at the same time I thought I'd replace the support bearing while I was there.

The end result - holy smooth Batman!
Gone is the rough jerky feeling between shifts - no vibration & a real solid driveline feel. (the above was all felt prior to the mount ripping) I guess the mount was getting weak when all of the above was happening?

Best of all the whole procedure was free of problems - the driveshaft came out without touching the e-brake cables, bearing came off and new one went on without any difficulties or "surprises". The only thing I was surprised by was that the flex disc bolts going to the trans. flange were a bit loose.

Vibration free in PEI

Aivars

Ken300D · #2 08-09-2002, 03:55 PM

I'm starting to wonder if the whine I hear is the differential after all. I wonder if it could be the center support bearing?

Which rubber mount are you talking about? The one at the back of the transmission? Or is there one at the center bearing?

I have a pair of flex disks on the way and am wondering if I should go ahead with a new center bearing at the same time. Did you replace just the bearing or did you throw in a new bearing dust seal - I think that's what its called.

Ken300D

#3 08-09-2002, 04:29 PM

Ken,

The center bearing is mounted in rubber. There is a dust shield on the spline that connects the front part of the drive shaft to the rear part. There is another rubber connection at the transmission and at the rear end (attaches the rear end to the chassis or subframe, I forget which).

I know these things because I removed my drive shaft three times trying to figure out what was causing a vibration. Finally discovered that the rebuilt shaft I was using had not been balanced correctly. What a saga.

Nic

ajb · #4 08-09-2002, 07:50 PM

Hi Ken,

Like Nic suggested, the centre bearing is pressed on the driveshaft and fits into a rubber mount that is bolted to the underside of the car.

The rubber mount supports (holds) the bearing and prevents the middle of the driveshaft from moving up\down or sideways. The rubber mount was ripped on my car and it let the middle of the driveshaft move up\down & sideways about 1-2 inches.

I replaced the rubber mount and while I had everything apart I thought it best to replace the bearing. (it was only $13 Can.)

If you are removing the driveshaft you should at least look at these parts.

Aivars

Ken300D · #5 08-09-2002, 08:27 PM

Is there anything special about getting the pressed on bearing off the driveshaft? Special tools or anything?

I'd like to do the complete job and not have to worry about it for another 20 years!

Ken300D

ajb · #6 08-09-2002, 08:42 PM

To get the bearing off on my 82 240d (after removing the driveshaft from the car & taking it apart) I had to take a C clip off - then using 2 finger puller I pulled the old bearing & rubber mount off. (it came off quite easy)

Using a pipe the same diameter as the inner race of the bearing, I drove/pushed/hammered the new bearing on the shaft. Installed the new rubber mount put the driveshaft together and installed it in the car. I basically just followed the instructions in my Haynes manual.

I was concerned about how hard it would be to remove & install the bearing - but it seemed to go quite smoothly. Like I mentioned in my first post- it went just about too smoothly considering it is a 20 year old car.

I hope this helps
Aivars

MVK · #7 08-11-2002, 03:40 PM

Ken;
Spray a lot of silicone spray on your center bearing on the propeller shaft. If it temporarily resolves the squeeking, then its your mid-shaft bearing and not your differential. This is how I detected my exact problem.

MVK

atombaum · #8 10-31-2002, 08:08 AM

This is with respect to my
1982 w123 240D / 289,000 miles:

I have replaced:
flex disks (2)
center support bearing and rubber mount
rear transmission mount
muffler
transmission "t" rubber mount

...but I still get a harmonic vibration that is the most pronounced between 60-65 mph.

Can you tell me of any other mounting rubber in the engine compartment (for the engine) that might need replacing? (290,000 miles).

What about wheel bearings or motor mounts?
Are these likely suspects?

Thanks for your help,

Jeff

#9 10-31-2002, 09:58 AM

Jeff,

I had the devil of a time eliminating a "harmonic" vibration in my '85 300CD. Tried everything, and I mean everything to include replacing both rear half-shafts.

Early on in the process I had my main drive shaft balanced and the universal joint rebuilt by a shop in Atlanta so I thought that was not the problem. Turned out that they didn't do the job right and the shaft was still out of balance. Caused me a lot of grief. When I finally replaced it with another rebuilt one my problem disappeared.

Moral of this story is that you need to consider having your drive shaft replaced or balanced, if all other simplier things have been done. There is a major truck repair company out of the west coast that offers rebuilt mercedes shafts at reasonable price (less than $200 if you give them your old one). I can't recall name so you'll need to research but if you can't find, let me know and I'll go through my paperwork. This is something you can do (remove/replace the shaft) if you are semi-competent and determined.

Good luck. I know how frustrating it can be to have this problem.

Nic

atombaum · #10 10-31-2002, 10:14 AM

I have not had the drive shaft out for any reason though. Would it just go out of balance?

atombaum · #11 11-09-2002, 02:02 PM

I replaced the center support bearing to no avail. Also did the motor mounts. No change in this
vibration. It is getting worse. When I put the car in drive you can hear it. Then the same noise sounds like a plane taking off at 60-65mph. I took it to a mechanic the other day. They mentioned a converter bushing. Where is the torque converter bushing? Internal to the converter or external? Does this sound like it might be causing the vibration?

Jeff

#12 11-12-2002, 09:34 AM

Jeff,

Wish I could help more but I just don't have the skill. If you hear the noise when the car is placed in gear but not moving, it about has to be the transmission or converter....not the drive train. I don't know where the converter "bushing" is.

Look carefully at the half-shafts as they have universal joints that can go bad.

Good luck. I know this can be frustrating. Take heart in that everything you are replacing/repairing probably needs attention anyway and your overall ride will get steadily better. You'll find the problem eventually (I did).

Nic

atombaum · #13 11-16-2002, 06:24 AM

Last night, I did the following:

(*) adjusted the front heat shield (maybe not by much, it looked to be clear of the pipe).

(*) tightened the kick-down solenoid connection at the transmission (it was very loose).

(*) adjusted the cable for the idle control (recently stopped working from the dashboard control knob).

(*) slightly adjusted the radiator position (not the fan shroud this time, but the whole radiator).

Took the car out for dinner and the noise was gone again. Also had kick-down for the first time ever.

Returned a video later in the evening to see if it was still "fixed" and no, it was not.

Jeff

atombaum · #14 11-16-2002, 06:27 AM

Oh yeah, and the kick down was also not working again when I took it out later that night. Could a vacuum leak be causing the transmission to make noise?

Last year I replaced a very worn looking vacuum line from the brake booster to the vacuum pump and the transmission started shifting great. I never expected that result.

Jeff

atombaum · #15 11-16-2002, 03:12 PM

I took the car to a friend's this morning (for 5 hours) and have the following items to report and a question or two at the end. I would greatly appreciate your comments.

To cut a long story short, there does not appear to be anything loose on the car that is causing the vibration/rumble at zero mph and/or at
60+mph.

What my mechanic friend was able to (sort of) "prove" to me is that the loud noise at 60+ is a drone that is engine or exhaust related. Note:
the entire exhaust system has been replaced very recently. We were going 65mph and put it in neutral and the engine revs decreased and the
noise disappeared. But why is the engine making this extra noise in the last 5 weeks? Read on...

Another discovery was when the car was on his lift and I had the engine running and the transmission was in "drive"...AND...my foot was on the
brake, the rattle/rumble noise was much worse. When I released the brake, the noise subsided or went away! I could turn the rattle on and
off like that depending on whether the brake was depressed.

He theorized and summarized that the problem that is causing the zero mph rattle and the noise at 60+ (which he showed me we can also hear at
lower speeds just before it shifts gears) is a torque related or transmission related problem.

He is not a Mercedes nut or a diesel nut, so his knowledge of how to correct this problem was nil.

Another thing he noticed and commented on: When the car is in drive and you release the brake, the car really wants to take off and go. He said that when the brake pedal is released, the car should just sit there waiting for input from the accelerator pedal. IS THIS CORRECT? (I have
a '66 250S automatic and an '89 260E automatic and this would be true for both of these cars). If this is true for the diesel automatic too,
then maybe I need to have the vacuum modulator and control pressures adjusted so that it does not "fight" to get going when sitting at zero
mph.

We both theorized that the "zero mph rattle/rumble" is connected to the car "revving too high before shifting" hence causing the "loud drone at higher speeds". All the same problem.

Also note that the kick down is working intermittantly. Vacuum leak? Adjustment?

WHAT DO YOU THINK?

Thanks,

Jeff

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