My pump may be getting tired also. Is the pump in my car the same diaphragm type pump as this? Also, can a leaking diaphragm allow crankcase oil to migrate out of the engine onto my driveway someway?

Thanks for your help,
Doug

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1980 Mercedes 300 SD, 215,000miles
2001 F-350 Powerstroke turbodiesel, Crewcab, 4x4, 81,000 miles
1993 Chevy Suburban, 185,000 miles

Hello!

I have done some testing with my 602 engine (W124). The symptoms were that the red stop lever got up after an hour or so. I can't exactly remember whether the lever used to stay down or not overnight. Anyhow, the engine shuts down perfectly but after the engine is shut down the lever slowly moves up (one can't see it but after an hour it's up all the way). Is this a leak or do the levers move up after some time?

I plugged the vac lines and found out that the leak is some place between the T from the brake booster where the line connects and the vac pump. The rubber connectors are well preserved and there is a one way vac valve to the brake booster. The thick plastic brake booster line is intact, there can be no leak. This makes me think it's either the one-way valve or the pump itself.

Yet, on the other hand, the vac from the pump, after the engine is off, disappears in a period of an hour and more. Maybe this is a normal occurence?

So the question is - after an hour the vacuum disapperas from the system, the causer is the vac pump thru which the vac leaks. Is this normal? Or, was the lever designed to stay down indefinately = the vac in the brake booster/shut-off circuits ought to be there for hours and hours?

P.S. Thinking of the one-way vac valve to the brake booster - after the engine is stopped, there is some vacuum in the lines. The one-way valve makes it possible for air to flow in direction brake booster => vac pump, right? Then it could be that the pump is tight but the air (thus the vac leak) gets sucked in from the brake booster. Should the thing be absolutely tight?