Horrible Clatter...Vacuum Pump - PeachParts Mercedes-Benz Forum

dazsa · #1 10-31-2007, 09:25 PM

My wife's 81-300SD started (all of the sudden) making a loud rattle from (I think) the vacuum pump. If the vacuum pump goes out, what happens and does it make a loud rattle? If it is not the vacuum pump, what else in the area would cause such a rattle? It is not a belt or the fan.

Thanks...as always.

Don

kerry · #2 10-31-2007, 09:30 PM

Dont' drive it. A failed vacuum pump can take out the timing chain. Ask Craig.

dazsa · #3 10-31-2007, 09:42 PM

Thanks for the info...

I think the item is the vacuum pump. It has the "wing-type" nut on the top of it by the secondary fuel filter. Am I identifying the right thing?

tangofox007 · #4 10-31-2007, 09:57 PM

Quote:

Originally Posted by dazsa

Thanks for the info...

I think the item is the vacuum pump. It has the "wing-type" nut on the top of it by the secondary fuel filter. Am I identifying the right thing?

That sounds like the power steering pump. Does it have a pulley and a drive belt?

bulletproofair · #5 10-31-2007, 10:18 PM

your vacuum pump is below the part you are referring to. You're referring to the power steering pump.

BUT if you are hearing a noise, you really need to pinpoint where its coming from, as the two components are pretty close together.

It sounds like the wing nut may not be holding the cap down tight enough, or the pulley is loose. Hopefully the pump reservoir is not empty, if it is, the filter could be wiggling around inside, though it is rather snug in there.

Take off the wing nut and the cap to see if you have power steering fluid though, just as a first check, while the car is off. If the wing nut and fluid are fine, then have someone turn the wheel full left or right (while the engine is running), and another person stand in front of the car to listen and watch the p.s. pump to pinpoint the noise. You'll probably find the noise just from the wheel turn with someone watching in the front.

If you find it IS the vacuum pump, do NOT drive. To see what the vacuum pump looks like, just go to a website that sells Benz parts and look up the vacuum pump and you'll probably see a picture. That way at least you'll definitely know what you're looking at.

#6 10-31-2007, 11:47 PM

Quote:

Originally Posted by kerry

Dont' drive it. A failed vacuum pump can take out the timing chain. Ask Craig.

Don't remind me.

Here is the ugly story, check out post #24 for ugly photo:

Stuck in NE - vacuum pump failed

Stevo · #7 11-01-2007, 12:12 PM

Be sure and check the end play of the timing device, as thats what caused the failure of the vacuum pump in mine as well as Craig's. Theres a bushing in back of the timing device that wares and causes the end play.

klaus kallas · #8 11-01-2007, 12:21 PM

Quote:

Originally Posted by kerry

Dont' drive it. A failed vacuum pump can take out the timing chain. Ask Craig.

I second this a million times over.

If you need a good pump, I have one here in Clayton you can have if you want to pull it. It is on an '83 240D engine that is otherwise bad.

Klaus
919-333-3182 cell

dazsa · #9 11-01-2007, 01:20 PM

Klaus,

Thanks. I will check everything out tonight when I get home.

Any suggestions to check the pump itself...mityvac or something like that?

Stevo, where is the timing device located?

Thanks

dazsa · #10 11-01-2007, 01:22 PM

Oh, can I start the car...I won't drive it, but can I start it?

klaus kallas · #11 11-01-2007, 01:42 PM

Quote:

Originally Posted by dazsa

Oh, can I start the car...I won't drive it, but can I start it?

I wouldn't run it for long. What you are facing if it is the pump that has gone bad is chunks of metal going into your crankcase via the timing chain housing. Not a pretty sight, especially if a piece goes between the chain and a gear!!

klaus kallas · #12 11-01-2007, 01:47 PM

I should be around this evening, so feel free to call if you need the part. The vacuum pump sounds like likely culprit, as power steering pumps don't tend to suddenly go bad. The vacuum pump is driven by the timing chain and uses a spring loaded cam (which is what tends to fly apart violently). Here is a link to a pic of the pump....

http://69.0.158.19/live/D300011694APG.JPG

Changing the pump is not real difficult, and be sure to get the stuff to do an oil change while you are at it.

darnold4014 · #13 11-01-2007, 03:22 PM

I recently had a similiar noise on my 1980 240d. I went ahead and replaced the vacuum pump but it still did not stop the noise. Later I found thet the A/C compressor had some missing bolts and was wobling back and forth creating a huge racket. I pulled that belt off and teh noise stopped. Might want to check that before you go ahead and replace the vacuum pump.
Dan

Stevo · #14 11-01-2007, 03:36 PM

Quote:

Originally Posted by dazsa

Stevo, where is the timing device located?

Thanks

The timing device is in back of the vacuum pump. The bearing on the V/P rides its little "roller coaster" track. (to get the pumping action for the pump) There shouldn't be more than about one mm of for and aft play when you pull it in and out. Mine had so much play (2.5mm+-) it chaffed a score mark in the back of the T chain housing.

then broke the pump. Just something too check when replacing the pump.

dazsa · #15 11-01-2007, 06:18 PM

IT WAS THE A/C HOUSING THAT HOLDS THE A/C BELT!!! The screws were almost out and the housing was wobbling around. It could not have been a "better" problem to have since I thought it was the vacuum pump. This evening was the first time I had to look at it in the light.

Thanks again and I learned a lot about the vacuum pump in this process!

I cannot thank you all and this site enough!

Don