Drive shaft support bearing? - PeachParts Mercedes-Benz Forum

Phil · #1 11-08-2011, 03:57 PM

I ordered new parts for the center suppport bearing but I was wondering if anyone has done this project on an 83 SD and if so do you have any advice. One write up that I've seen says I need to unbolt the rear of the transmission and cross member so I can lower it, another says I have to remove the exhaust pipe. Also it says I need a 46 mm wrench and a 41 mm wrench. I am trying to find a source for these if anyone has any suggestions let me know? The only 46 I have found was over $100. In the MB manual it sounds like there are some slight differences between 82, 83 and 84.

vstech · #2 11-08-2011, 04:38 PM

Hmm, I've been under the 126, my 83 is currently on the back of my car hauler. ya want me to go snap some pics for ya?
to get the driveshaft down, I'm sure you have to drop the exhaust, and the driveshaft tunnel cover.

Phil · #3 11-08-2011, 06:35 PM

Quote:

Originally Posted by vstech

Hmm, I've been under the 126, my 83 is currently on the back of my car hauler. ya want me to go snap some pics for ya?
to get the driveshaft down, I'm sure you have to drop the exhaust, and the driveshaft tunnel cover.

I was under my car last weekend and it doesn't look bad getting the tunnel cover off. I'm hoping I can just drop the rear of the exhaust and leave the front connected. Until I get the cover off I can't tell if I need to do all the unbolting of the tranny.

vstech · #4 11-08-2011, 06:41 PM

it's not much more work to drop the down pipe.
just pull the air cleaner out of the way, M.A.W. change the air cleaner mounts too...
I think the front section may not be much in the way, but if it is, you may be able to disconnect the u-bolt, and loosen the downpipe nuts, to give you some wriggle room.
I'd not try pushing on the down pipe, if you still have the original flex connector... it's fragile if moved much.

BodhiBenz1987 · #5 11-08-2011, 06:51 PM

I've only done this on a 123 and 124 so I'm not of real help with the specifics, but regarding the hard-to-find giant wrenches, you might want to look for large crescent wrenches ... I used two, one large and one slightly smaller, to get the large center nut undone and done again. Harbor Freight has a wide selection ... not that they're the highest quality tools but they got the job done.

compress ignite · #6 11-08-2011, 07:08 PM

$10.68 @ Advance

compress ignite · #7 11-08-2011, 07:13 PM

$11.06 @ Advance

vstech · #8 11-08-2011, 07:55 PM

the nut is super easy to remove, I used a vice and channel locks on my 123...

Diesel911 · #9 11-08-2011, 11:31 PM

I removed the 46mm Nut with a chain type Pipe Wrench but bought a cheapie Combination wrench in the close American size I believe it was 1-13/16" for about $12.

However, I like the Crows Foot wrench idea better.

Before you tighten that Nut it is said you need to put the Car down on all wheels and push the Car back and forth a little to allow it to settle in and allow the shafts not to bind (in neutral?); and then tighten it up.

Diesel911 · #10 11-08-2011, 11:33 PM

Quote:

Originally Posted by compress ignite

$10.68 @ Advance

Thanks for this info. The Cows Foot allows you to actuall torque it properly (which I did not do to mine).

There is also Wrenches for ATVs that are in the needed sizes but are about $20 each.

Phil · #11 11-09-2011, 12:36 AM

I don't have Advance around here but I'll check O' Rileys, AutoZone or Pep Boys. Napa can get one but the price is way to high.

The Gears · #12 11-09-2011, 02:49 AM

I have done this job on a 84 123 and 84 126 several times over the years.
Removed the tunnel cover. Using a chain wrench on the shaft and a big Crescent wrench to turn the nut. Undo the four bolts that hold the diff to the frame and drop in on a floor jack four inches. This move is easy and makes the job real easy, no prying on the flex disks. Leave the exhaust in place. Leave the trani mount alone.
Mark the two half's of the drive at the universal, must go back in the exact way.
Slide the shaft out the rear over the exhaust pipe. Enjoy the job.

vstech · #13 11-09-2011, 07:22 AM

Quote:

Originally Posted by Diesel911

Thanks for this info. The Cows Foot allows you to actuall torque it properly (which I did not do to mine).

There is also Wrenches for ATVs that are in the needed sizes but are about $20 each.

keep in mind when using a crowsfoot wrench with a torque spec.
the head extends past the center of the wrench, so some calculation is needed, or you must find the point in the rotation where it's closest to neutral offset.

SD Blue · #14 11-09-2011, 09:52 AM

I've had my driveshaft in and out several times. This was due to taking the car to someone who didn't know what they were doing. The end result was flex discs in backwards, a shredded carrier bearing mount, all kinds of missing/wrong bolts, bolts in backwards and a vibration that I can't quite seem to get rid of a year later. So the first advice I have to give is to study the write-ups on this forum and do it yourself or at least take it to someone who works on them day in and day out and is familiar with MB's of this vintage.

First, make sure you have everything to raise the car, to a significant height safely! Back-up fail safes need to be used. It's not that hard as even a spare tire under one of the rear wheels is enough to save your life. Then mark everything clearly, with "clocking" orientation, before you take it apart. The car drove smoothly for many years this way and might save you some of the vibration grief that I've had. You can either drop the differential or the exhaust to give you access. I've used both methods and thought lowering the exhaust was the easiest. I left the down pipe attached at the front with no issues. However, if it appears that rust and an exhaust leak might be an issue then it's your call. The lock ring on mine loosened with a couple of large adjustable wrenches. Even after 300K miles, it was fairly easy to loosen. It's not a bad job but it depends on how well "lubricated" the undercarriage of your car is from persistent, or previous, oil leaks.

Junkman · #15 11-09-2011, 12:16 PM

I just did my SD. I jacked the rear,
supported the exhaust near where the rear half is bolted to the back,
Removed the back 1/2 of the exhaust but left it under the car. (Buy new exhaust donuts they are cheap)
removed the exhaust shield,
Disconnect rear of drive shaft
Support tranny & drop cross member per FSM
Disconnect front of drive shaft
drop carrier bearing.

Replace both flex disks because they had cracks.
They are marked (ouf Deutch). Per FSM, markings mean "toward drive shaft)
Remove centering bushings (drill, insert round prybar, spray, twist, pound, cuss)
Pound (tap carefully) new bushings
Replace center bearing
Replace bearing carrier

Note how flex disks attach and orientation of bolts. Mine were socket head cap screws & new bolts, washer, nuts were supplied with flex disk.

Note orientation of bearing support. It only goes 1 way but pics would be helpful. (I didn't take any.

)

Note and mark how drive shafts were put together. They are marked and balanced from the factory.

Install - Proceed vice versa.....