Is there any way to cover up the exposed bearings on an OM617 vacuum pump? - Page 2 - PeachParts Mercedes-Benz Forum

Stretch · #16 04-30-2013, 02:21 AM

Quote:

Originally Posted by Mark DiSilvestro

...
As for the lever breaking, that's usually when severe engine damage occurs. If the pump fails on a long trip, there may be no noise, or warning, until the driver needs to use the brakes.
That happened to me on my TD, fortunately near the end of a trip to Virginia Beach. In my case the brakes were normal when I used them at the Hampton Tunnel, but had completely lost vacuum when I took my exit off the Expressway into Virginia Beach. So my pump bearings failed somewhere within that 20-mile distance. When they failed, what was left of the 12 balls spilled into the timing-chain cavity, and somehow passed harmlessly through into the oil-pan, where they became trapped by the oil-pump pickup screen. When I got to my destination and removed the pump, the bearing races and lever were still attached, but the drve cams had begun carving a significant slot in the lever.

After the experience with my '84 300TD, a similar one with a friend's '84 190D, later reading threads here and talking to 'JohnHef' who has posted here and is a longtime Mercedes dealer mechanic, the consensus is that there's a good chance the bearing-balls will pass harmlessly into the oil-pan, but continued driving eventually destroys the lever, causing catastrophic engine damage when the lever-fragmants hit the timing-chain!

Happy Motoring, Mark

In your case - did you not hear any noise as the vacuum pump started to deteriorate?

Mark DiSilvestro · #17 04-30-2013, 09:04 AM

Quote:

Originally Posted by Stretch

In your case - did you not hear any noise as the vacuum pump started to deteriorate?

At 60 - 70 mph, with the typical engine and road noise, not a sound from the vacuum-pump. I'm just happy the pump didn't fail sooner and let me drive another 50 - 100 miles until the lever shattered. I'm sure I would've heard something them!
In my case, It wasn't until I hit the brakes about 3 miles from my home that I realized the brake power-assist was gone.
When I arrived, the engine wouldn't shut off, and there was no other visible underhood damage to the vacuum system. So that kind-of confirmed the pump had failed.
Thankfully, on these cars it's easy to drop the lower oil-pan, and remove what's left of the bearing-balls & plastic from the pan & oil-pump screen.

A few years earlier, before I'd had much experience with these diesels, a friend went to a car aucion and bought his very own 'Nightmare Mercedes' - an '84 5-speed 190D, with 400K miles, and a broken vacuum pump in the trunk! He found a used pump for me to install, but didn't want to explore any further.
The car ran fine until two months later, when his aluminum timing cover broke where the belt tensioner was attached. Apparently, that's a problem on some of these newer generation diesels.
I had to jack the engine off the mounts just to drop the oil-pan and change the timing-cover. And I still couldn't get the pan completely out. Only down far enough to reach up in there and grope around for the loose balls!
Four months later, when the tranny started making loud noises, he sold it!

Happy Motoring, Mark