replaceing fuel primer pump
 

My Primer pump seems to leak. How do I tell if I have an "old one" or the "newer one"? Also there is a Gasket PN # 2010-70168. Does it fit between the bottom of the primer pump body and where the primer pump screws into the main housing?

Thanks in advance Russ

On my 1983 300SD the old one had a white, serrated edge, plunger top and you would unscrew the plunger before pumping.

The new one which replaced it (the old one leaked) has a black sprung plunger which you simply push with your thumb. No unscrewing needed. You can see a picture in my maintenance piece on my web site.

As this is a 617 specific question, I would guess there is no difference between the W123 chassis (yours) and the W126 (mine).

Where else could the gasket fit?

Well if it leaks you need to replace it so it doesn't matter which one you have, I think you can only get the newer one now. And yes that's where the gasket goes. Thomaspin's web site will be very helpful also but it is an easy job.