What could have happen??
 

I just got back from Nashville, and started to turn in my drive, and I had to push hard on the brakes for them to work. Then, the engine started to rev up and when I turned the ignition switch to off nothing happen - I went under the hood and pulled the throttle cable until it died. Any ideas as to what happen. I'm going now to take a look, but it sure would be helpful to know what to look for. I appreciate any help. Thanks.

Hugh Sr

1984 190d (w201/601)

hmm

This would be explained by a vacuum failure. Before jumping directly at the pump itself, make sure that the main vacuum connection hasn't somehow slipped off of the vacuum pump on the engine. When your engine was running, was it making any abnormal noise like a ticking or knocking at all? Time to take out the mityvac and begin testing to find the source of your leak. I would begin at the Brake booster and work backwards, replacing a vacuum pump is pretty much a last resort (though probably the most common vacuum failure other than ruptured hoses).

The hard line that runs from the vacuum pump to the brake booster. About the middle a small hose runs off of that. I hooked up my mityvac, cranked her up, and I did not get any reading on the gauge. I put a long piece of wood on the vacuum pump and listen at the other end. I heard a fast clicking sound of metal hitting metal. You know, I just put an oring on my injector pump last week to solve an oil leak (it did), and I put a new gasket on the vacuum pump. But would a small leak cause what happen to me? Thanks

Hugh Sr

1984 190d (W201/601)

The line that runs from the vac pump to brake booster and has a fitting, that line is the one that controls the shut off to the pump. With the car off, apply a vac or suck on that line you should see the shut off arm on the pump go down. If it does that shows the ignition switch shut off is all ok. You might have disturbed something.

Check the vac at the pump. then chase from there.

Do I take the hard line on top of the vac off, and check it there? I know that sounds a little bit stupid, but it's my first time. I have a mityvac. If that is the first place to check the vacuum, and my gauge does not show anything, then does it mean the v/p is shot. If it is can you rebuilt those? I noticed that they start around $300. Thanks for your help. O yes would the v/p check valve make a difference? Where is it.

Hugh Sr

1984 190d (W201/601)

There are vacuum pump rebuild kits available but it really depends on the type of failure of the pump. You could probably find a good used one by keeping an eye on the parts section of the forum here.

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