W108 Carrier Bearing Replacement - PeachParts Mercedes-Benz Forum

Bezant · #1 10-14-2018, 12:04 AM

Hi all,

I want to replace my driveshaft carrier bearing. I can wiggle the driveshaft around in that section by hand.

I have the bearing, the donut bushing and the rubber sleeve ready to go in.

The manual basically says, remove the entire exhaust and rear engine mount etc. I have only a couple hours of shop time with a lift and I work pretty slow. Is it possible to do a short cut and get the job done any easier?

Idle · #2 10-17-2018, 03:53 PM

I don't think you really need to remove the rear engine mount, actually transmission mount, but the exhaust system will have to be dropped.

And when you have the driveshaft out be sure to mark the two halfs with a line of some sort so it can be reassembled in the same way. These are balanced at the factory as a unit and if you get it out of sync you will get a lot of vibration.

And marking the front and rear with a piece of chalk or a strip of tape is easy.

Be careful not to knock off any of the balance weights. I have seen these attached to the driveshaft in two ways: Spot welded, sometimes called tap welded, and just glued on. If you knock one off then pick it up and glue it back on with the strongest glue you can find. Then clamp it down and let the glue set. These weights are small squares applied here and there.

One way to speed this up is to have a helper or two. This comes out easy, it can be tough to line back up.

But all it in it is rather simple.

Idle · #3 10-17-2018, 03:55 PM

And....

The nuts holding the front to the back are rather large. I use two big monkey wrenches to grab down on the nuts and break them free. I don't know what size these nuts are but unless you are a serious shop I doubt that you have them.

Just buy or borrow two big monkey wrenches.

Bezant · #4 10-17-2018, 11:21 PM

Quote:

Originally Posted by Idle

I don't think you really need to remove the rear engine mount, actually transmission mount, but the exhaust system will have to be dropped.

And when you have the driveshaft out be sure to mark the two halfs with a line of some sort so it can be reassembled in the same way. These are balanced at the factory as a unit and if you get it out of sync you will get a lot of vibration.

And marking the front and rear with a piece of chalk or a strip of tape is easy.

Be careful not to knock off any of the balance weights. I have seen these attached to the driveshaft in two ways: Spot welded, sometimes called tap welded, and just glued on. If you knock one off then pick it up and glue it back on with the strongest glue you can find. Then clamp it down and let the glue set. These weights are small squares applied here and there.

One way to speed this up is to have a helper or two. This comes out easy, it can be tough to line back up.

But all it in it is rather simple.

Thanks. Do you have to fully remove the exhaust or could you just move some of the rubber hangers and get enough clearance?

I have big wrenches and sockets as it's at my university's auto shop.

Idle · #5 10-19-2018, 01:20 PM

Quote:

Originally Posted by Bezant

Thanks. Do you have to fully remove the exhaust or could you just move some of the rubber hangers and get enough clearance?

I have big wrenches and sockets as it's at my university's auto shop.

I am almost sure you have to remove the entire exhaust system. But it's not that big of a job. You have the rubber hangers to disconnect and usually two bolts, or three, at the front of the pipe. You don't have to remove the downpipe.

The tunnel that runs down the middle of the car houses not only the drive shaft but some of the exhaust system. So it is right in your way.

But if you can get it out without dropping the exhaust then you are that much ahead. I always remove the exhaust system because it gives me a lot more room to work with and really it's not all that hard to do.

This is an excellent time to replace all the rubber hangers. They are cheap and tear up easily when you are removing them. And if you a full set of new ones you can just cut the old ones. This makes the removel job even easier.

Bezant · #6 10-19-2018, 04:30 PM

Quote:

Originally Posted by Idle

I am almost sure you have to remove the entire exhaust system. But it's not that big of a job. You have the rubber hangers to disconnect and usually two bolts, or three, at the front of the pipe. You don't have to remove the downpipe.

The tunnel that runs down the middle of the car houses not only the drive shaft but some of the exhaust system. So it is right in your way.

But if you can get it out without dropping the exhaust then you are that much ahead. I always remove the exhaust system because it gives me a lot more room to work with and really it's not all that hard to do.

This is an excellent time to replace all the rubber hangers. They are cheap and tear up easily when you are removing them. And if you a full set of new ones you can just cut the old ones. This makes the removel job even easier.

I recently did all the hangers. Just a little worried about stripping a bolt on the manifold which has happened on other cars lol.

Bezant · #7 10-27-2018, 11:53 PM

Ok all done! Took 5 hours cuz the exhaust was a pain in the butt.

The donut was still soft but had collapsed and had a ton of movement. The bearing was rough and scratchy.

My vibration at 55mph is gone!

alant912 · #8 10-29-2018, 11:29 PM

Nice work Bezant!

I replaced the bushing donut over the weekend on my 70 280se, but couldn't get the carrier off the driveshaft to replace the bearing.

Is there a clip that needs to be removed first, or should the carrier just come off the driveshaft with a puller? I tried a 3 jaw puller on the aluminum hub, but she wouldn't budge for me.

Idle · #9 10-30-2018, 11:43 AM

Now that't the way to mark the shafts.

A fun fact: On the four cylinder 230's that were built up to 1976 the engines were so short the transmission needed to be moved forward a few inches. Mercedes decided that a two piece driveshaft would be too long and would induce vibration.

So they used a three piece driveshaft. With two carrier bearings.

There are not many of these left running, but if you have one be ready for a fun filled day of wrangling a three piece drive shaft which no one in the US is set up to balance.

Bezant · #10 11-04-2018, 12:20 AM

Quote:

Originally Posted by alant912

Nice work Bezant!

I replaced the bushing donut over the weekend on my 70 280se, but couldn't get the carrier off the driveshaft to replace the bearing.

Is there a clip that needs to be removed first, or should the carrier just come off the driveshaft with a puller? I tried a 3 jaw puller on the aluminum hub, but she wouldn't budge for me.

hmm you loosen the big nuts to separate the halves, then there are two circlips on both sides of the housing for the bearing.