B2 Piston Upgrade - PeachParts Mercedes-Benz Forum

tomm9298 · #1 01-07-2005, 09:30 AM

Is there a way to verify if your B2 piston has been upgraded? Short of transmission removel. Thanx.

Pete Burton · #2 01-07-2005, 09:49 AM

Start with the serial # on the transmission casing. You can search from there

#3 01-07-2005, 09:59 AM

If you really want to know you may have to remove the B2B, you can do that in about a 1/2 hr. It is not that hard to do. Only problem then is to identify whether the one in there is the old style or the upgraded version. The upgrade version has a wide teflon seal around the circimference, as I recall. But without the new and the old style side by side you will have a problem identifying the difference.

vwkess · #4 01-07-2005, 10:01 AM

I don't think the transmissions came with the updated pistons until the late 80's. You don't have to pull the transmission to check, just remove the piston cover. Good time to check if you have the updated piece is when you are changing your trans fluid and filter. This is what the updated one looks like http://transmission.articles.mbz.org/b2/intact.jpg

tomm9298 · #5 01-07-2005, 11:25 AM

As usual this forum and it's GREAT members come through again.

#6 01-07-2005, 11:31 AM

http://ac.unpatented.com/pics/trans/brokenb2b.jpg
This is what a broken one looks like. See the difference?

Somehow I wonder if I did not have an updated B2B that gave out anyway.

pdxwaker · #7 01-07-2005, 11:35 AM

Quote:

Originally Posted by Old Deis

If you really want to know you may have to remove the B2B, you can do that in about a 1/2 hr. It is not that hard to do. Only problem then is to identify whether the one in there is the old style or the upgraded version. The upgrade version has a wide teflon seal around the circimference, as I recall. But without the new and the old style side by side you will have a problem identifying the difference.

Is this assessment for a W126 or a W123? From the article at http://transmission.articles.mbz.org/b2 it sounds like the W126 is much easier than the W123 ("The good news is the repair can be made while the transmission is in the car in the case of a 126 - other chassis the trans needs to be dropped although people have reported success, with some effort, of doing it to 123 and 107 chassis with the tranny in place").

Maybe 1/2 hr is a bit optimistic for a W123?? I'm not sure since I've never done it myself... just trying to understand what I'd be getting into before starting such a repair.

-John

#8 01-07-2005, 11:47 AM

Hmm. never done this on a 123. They do use essentially the same transmission though. Biggest chore is that you have to remove the trans mount to get a clear shot at the cover there on the rt side of the transmission.
From what I can see the 123 is a bit more crowded in there. Could be that you would have to remove the driveline also to get the rear of the transmission to drop down enough to get to it. Also if it has a mechanicle speedometer that would have to be disconnected.