Vacuum pump lesson learned

[tesavage]

Originally Posted by James L

So what worked? the new o-rings are the old? I am getting ready to do this on my 1984 300SD as my rebuild kit will be here friday! Can you walk me through it!! I have the MB cd and it talks about a special clamping tool?

You will need to reuse the old o-rings, otherwise you'll drive yourself mad trying to figure out why the rebuild didn't work.

The pump is really simple to rebuild. This page pretty much contains everything you need to know. You can mount the pump on a board with a small wooden block under the rocker arm in lieu of the clamping tool.

I'm not sure that it is really necessary to remove the piston rod assembly if you're rebuilding because of a vacuum loss situation and not a mechanical failure. Do inspect the rocker arm bearings and movement carefully for wear, though. Removing it just isn't very likely to tell you much more.

The rebuild kit doesn't include a new pump-to-engine block gasket. I assumed it would (before finding the above link), and ended up buying one at the dealer for ~$6.00. It is part no. 616 011 03 80 in case you still need to order it.

Good luck!

Tom