Where do old vacuum pumps go? (OM603) - PeachParts Mercedes-Benz Forum

Jeremy5848 · #1 06-15-2008, 09:54 PM

I was a good boy last week and changed the vacuum pump in my '87 300D-T (W124, OM603) before it spit shrapnel into the timing chain. The pump I removed looks great, of course, no sign of wear or damage at all. So what do I do with a perfectly good but fatally flawed (open ball bearings) vacuum pump? My parents lived through the Great Depression and I was taught not to throw things away that might be needed some day . . . but this is not something I wanna keep.

Hatterasguy · #2 06-15-2008, 10:00 PM

Mine is in the basement to be thrown into my dads scrap metal pile at a later date.

If you know someone who collects scrap metal throw it in their pile, aluminum is up their.

sixto · #3 06-16-2008, 01:10 PM

Good question since no seller takes the old one as a core.

Disintegrating bearings leads to catastrophic failure but the seal behind the front cover gets deformed and leads to an annoying front end leak. Should be a simple matter to straighten the tabs and have a look inside the pump to determine why it's not rebuildable.

It would be great if someone could retrofit 617 pump guts into a 603 case. You never hear of 617 pump drives disintegrating. I've done a simple rebuild of a 617 pump on the engine to get the brakes working so I could get the car for free!

Sixto
87 300D

Jeremy5848 · #4 06-16-2008, 04:18 PM

Quote:

Originally Posted by sixto

. . . Disintegrating bearings leads to catastrophic failure but the seal behind the front cover gets deformed and leads to an annoying front end leak. Should be a simple matter to straighten the tabs and have a look inside the pump to determine why it's not rebuildable. . .

An interesting point. What is it that makes the 617-type vacuum pump rebuildable and the later 603-type not? Is it that no one ever bothered to offer a kit? Or is it really something different about the pump? (I've never had a 617 pump off to look inside.)

Jeremy

TX76513 · #5 06-16-2008, 04:25 PM

Quote:

Originally Posted by sixto

Good question since no seller takes the old one as a core.

Disintegrating bearings leads to catastrophic failure but the seal behind the front cover gets deformed and leads to an annoying front end leak.

Sixto
87 300D

Cr@p that's were this leak just started from (light goes off in head) I changed mine out last Dec., but just started this weird leak - Sixto is it the vacuum pump seal or do you speak of some other mysterious less discussed seal?

sixto · #6 06-16-2008, 11:41 PM

What I'm talking about is the seal between the brass front cover of the pump and the pump case. I think that's why they added the screws in later designs.

I haven't heard of a new pump design leaking but I've heard of folks who replaced the gasket between the pump and timing chain cover only to have the leak continue.

Sixto
87 300D

ridgerunner · #7 06-17-2008, 01:53 PM

It's fairly simple to get the pin out that the bearings and roller rides on. Has anybody ever took the bearing # and went to a bearing shop and cross over to a sealed bearing? Just wondering because I've got the open bearing myself.

Jeremy5848 · #8 06-19-2008, 03:51 PM

Discovered a use for the old pump after seeing that my new pump wasn't so much of a bargain after all (let that be a lesson to y'all!). Turns out the pump won't hold vacuum after the engine is stopped -- the check valve leaks. I took the main vacuum line off of the pump and attached my Mityvac; it pumps down but leaks back in about five to ten seconds.

I experimented with the old pump, discovered that the check valve and piston of the pump work together to prevent air from moving back into the vacuum lines. The old pump will hold a vacuum for days -- I have a gauge permanently installed in the main line and have watched it for months.

I plan to let the new pump be for awhile, maybe the parts will wear in and seal better after a few miles. I don't know if swapping out just the check valve will help. In the meantime, there don't seem to be any ill effects from not having vacuum, since the door locks have their own pump.

Jeremy

Hit Man X · #9 06-19-2008, 09:43 PM

Recycle it.