Close call with vacuum pump - PeachParts Mercedes-Benz Forum

Stevo · #1 10-11-2007, 07:55 PM

I have an "82" 616 on the engine stand that I pulled from a car that had a cabin fire. It needed a new rear main seal which i completed today anyway when I removed the oil pump screen I found a couple 'finger nail clipping' size pieces of metal. I pulled the vacuum pump and sure enough that round plate inside was blown out (or "blown in") in the center with chunks of metal setting back inside with the springs

From the looks of the metal in the pump and what I found in the O/P screen, I dont think theres much missing but I'm wondering
what if anything I should do beside button it back up and hope for the best. I have the crank and rod caps all torqued.

#2 10-11-2007, 08:46 PM

I don't know what you've done with the timing chain and sprockets, but I would take a good close look at them to make sure none of these pieces did any damage on the way to the pan.

Stevo · #3 10-11-2007, 10:40 PM

I did pull the timing chain out (replacing it anyway) and stuck the air nozzle down there with the engine rotated at different angles and I dont see any damage to sprockets.

#4 10-11-2007, 10:53 PM

Sounds like you were pretty lucky.

Stevo · #5 10-12-2007, 12:37 AM

Do you happen to remember the allowable amount of end play in that timing device shaft, I cant find anything in the shop manual about it. There definitely seems to be what I would think is too much.

Stevo · #6 10-12-2007, 03:35 PM

This morning I found the end play of the timing device to be 2.3mm, seems like way to much. I pulled the intermediate gears and timing device and found the large bronze bushing on the horizontal intermediate shaft to be the culprit that wears down, there are "notchs" diagonally on the ends of the bushing so as ware occurs the notchs go away and you can see its condition at a glance Since the engine is out of the car it was an easy job but wouldn't think it would be bad in the car. Haynes has good shots of everything. Anyway check for end play of the timing device when the V/P is out.

#7 10-12-2007, 05:42 PM

I had that bushing replaced in my 617 a while ago because there was a little "vacuum pump type" noise and my indy thought there was too muck axial play. As I recall, he said there should only be about 1 mm, but I don't have the specs. It seem like kind of a PITA in the car, he ended up having to retime the IP too.

Stevo · #8 10-12-2007, 08:55 PM

Ya, sure, I remember your post and how I thought it odd as I'd never heard of that problem, LOL, I've never checked the end play on a timing device but you can bet I will from now on. The T/D went so far aft that it chaffed a grove in the back of the chain case. That "slop" must have caused the V/P too fail. I have it all replaced now with parts from a low millage "parts" engine and there is maybe a mm of play. I 'm waiting for the sister link for the T/C

#9 10-12-2007, 09:01 PM

I suspect that's what happened to mine too, my new VP only lasted about 60K miles before it started to develop a little click. It seemed OK out of the car but it was making a little noise that when away with a new pump. I would also be concerned about the TD putting a side load on the TC if it wasn't fixed. How many miles do you have on that engine?

Stevo · #10 10-13-2007, 11:06 AM

This engine has around 230K. I had never heard it run but I know the guy that took care of it for the lady that owned the car. He told me about the rear seal needing replacing.

I took the oil pump apart and the bushings and impeller teeth all looked good as new so I will reuse it. I dont have a working camera anymore or I would have taken some pics. I think the hard part of the job would be getting the T/D out and back in with the T/C in place. As to re timing, the IP must be removed as the intermediate comes out from that side.

Anyway, thanks, your post alerted me too the end play of the T/D.