time to rebuild vac pump? - PeachParts Mercedes-Benz Forum

JHZR2 · #1 12-02-2003, 06:53 PM

I pulled my radio today, to find it coated with a thin layer of black oil. I noticed the same thing on my ignition tumbler, by where the vacuum line goes in for shutoff.

is this a sign that my vacuum pump needs to be rebuilt, as it is letting oil past the seals? how dificult a job is it on a 300D turbo?

Thanks,

JMH

Fisherman · #2 12-02-2003, 07:46 PM

I think what you have found is oil traveling back up the vacuum line from your shutoff valve on the back of the IP. Remember it "pulls" with vacuum from the shutoff valve on the IP to the key switch to the feed line coming off the main brake resevoir line etc... to shut off the flow of diesel. It can be replaced without taking the IP off the car but there is very little room to get it to hook back onto the control arm inside the IP.
I have pulled them off engines though without too much work. 4 bolts and then remove it. As I remember it wants to turn towards the block in order for the bend on the end to disengage the control arm inside teh IP. The end of the arm is simply bent 90 degress to "hook" the control arm in the IP.
These valves get ugly after a while and the oil travels back up to the switch and then leaks down onto the under dash panel and creeps into the center console onto the top of the radio. Ask me how I know...

Fisherman · #3 12-02-2003, 07:48 PM

The vacuum pump failure will show by producing oil in the outlet line (remember vacuum) not on the lines that go into the car to service all the vacuum accessories.

samiam4 · #4 12-03-2003, 01:14 PM

I'd investigate quickly...

Diesel oil in the dash is a NASTY mess to cleanup. Also, the oil pressure gauges is suppled from the engine. Make sure it is NOT leaking.

Michael

JHZR2 · #5 12-03-2003, 01:54 PM

No, I really thought it was coming from the climate conrol unit due to some oil in those lines...

I know the ignition tumbler leaks a bit... But its definitely not the oil pressure gauge. I'm pretty sure Id know if that was leaking.

JMH

Fisherman · #6 12-03-2003, 05:40 PM

It could be the ACC if the vacuum pump actually reversed and pumped pressure.
When I got my 300 the top of the stereo was covered with oil and I traced it back to the shutoff on the key switch. The old rubber fittings that connect there had gone all soft from all the oil and were leaking.
Check the hoses up there by pulling the kick panel on the drivers side. You can then reach it pretty easily and I'll bet you will get oil on your fingers when you reach up there.