B2 Piston o Ring - PeachParts Mercedes-Benz Forum

gozapper · #1 01-09-2013, 06:55 PM

I am in the process of replacing the B2 Piston on my 83 300SD. I nicked the red o ring and removed it. Got a new o ring from dealer and it seems to be a little larger diameter
than the bore. The original o ring also is larger than the bore. How can that be?
I tried to put the new one into the groove and it is just too much to fit.
The part # 005 997 70 48.

I have read on this forum that this part is hard to install while transmission is still in the car.

Any tricks will be appreciated.

Tom

Diesel911 · #2 01-09-2013, 07:18 PM

005 997 70 48 is the part number I used on mine and it was a genuine Mercedes part.

I had a hard time getting mine in also; after some 30 minuts or so of oath swearing I took a break and tried again and it finally went in.

I can't think of any tricks except that I felt I could have used a third hand to hold in what I alread had in the groove and would pop out when I went over to the other side.

That means if you can get someone to help hold some of it in the groove on one side I think it would be easier.

If you can avoid twisting the part that you actually do get into the groove.

Diesel911 · #3 01-09-2013, 07:21 PM

I just thought of the and I have no idea if it will work or not.

Put the O-ring in the Freezer 3 hours or so. That might shrink the outside diameter a little and at the same time make it stiff so it might not pop out of the groove so easily.

If you try this let me know if it works.

ah-kay · #4 01-09-2013, 07:22 PM

It is the correct part # and it IS slightly bigger. The trick is to use some vaseline jelly to hold the o-ring in the slot. Then gingerly push the cover back in. You are pretty much on your own if you are under the car lying flat. If car is up in a lift or the tranny is out then may be you have the space for a helper.