W115 Injector Pump Part Question
 

My IP is at a local Bosch shop for a rebuild.

They got the rebuild kit for the internals from Bosch. The diaphragm is an MB part.

They are having difficulty getting the IP governor to seal completely. As I understand it, the new diaphragm is working well but there is a still small vacuum leak at a rod coming near the back.

Without the IP in front of me I'm not quite sure what they're talking about but perhaps someone who's replaced diaphragms might.

Anyway, is this a common problem? Does MB carry the part or is it Bosch specific?

The shop likes using Bosch parts for obvious reasons. However, there was almost a $150 price difference between the Bosch supplied diaphragm @$225 and the MB part at @$85. If the same logic holds this time around, I'd be saving an appreciable sum of money with MB should it be available and could point the shop towards that side of town.

Thanks!

The below .pdf names several parts where there can be a leak.

It may be the bore of that shaft you were speaking of is worn and the O-rings will no longer seal it well.

Thanks for the post.

There's not much there to replace....

Yes, but it still has to be re-assembled correctly.

It could be no one at the Shop has ever rebuilt one before.

The old Bosch Film Fisch from the past that had the instructions is difficult to follow due to translation issues and the pics are tiny and dark; hard to see.

It can leak at the axle of the poppet cam, see red circle below. MB sells the entire back cover (blue line), usually expensive, you can also replace the bearings and O-rings, the parts can be ordered from Bosch and you have to do the work yourself. Sometimes the back covers can be obtained from other sources.

http://i185.photobucket.com/albums/x...cgovernor2.jpg

I hadn't checked this thread for updates. Sorry for getting back so late.

Yes, the rear housing was the culprit. They got it from MB for a pretty reasonable sum.

The old diaphragm actually looked pretty good for a 40 year old piece of leather. There was one small tear, but it's still servicable.

All in, parts ran $170. That included the Bosch rebuild kit, MB diaphragm (Bosch wanted $220, MB $75ish), two mounting gaskets, and the rear cover.

Cooler still was the shop delivering it back to me.

They have a driver running all over the state and he happened to be coming through my area this run, so he dropped it off. Now that's service!

It saved me a 90 minute drive each way to Charleston.

If anyone's curious, PM me for the final cost and the contact info for the shop. I don't want to run afoul of any advertising prohibition.

One of the Moderators can answer for sure.
I do not think any of our Sponsors are Fuel Injection Shops so the Shop that rebuilt you Pump would not be a competitor.

Sorry to resurrect an 8 year old thread but was hoping you had the part numbers for these handy?

Many thanks!

If there is any tear or hole the Diaphragm needs replacing.

Some of the info may be in the links on replacing the Governor Diaphragm.

Repair Links

Fast navigation http://www.peachparts.com/shopforum/diy-links-parts-category/146034-fast-navigation-do-yourself-links.html

There is a plate on the Fuel injection Pump with the Pump numbers. Any Bosch certified fuel injection shop should be able to look up the gasket kit.

But if you go to an official Mercedes parts seller that has the exploded diagrams of the parts you may find that they sell it.

I think the last word on it was that Mercedes sold the diaphragm cheaper but that was a few years ago.

You could also look over on the benz world . org forum