I just bought an 87 300td. The brakes periodically will have no boost for the first minute or so the car is running or until I freak out and pump the living hell out of them. Then they're fine. The other day I had the brakes not there for me even after repeated pumping and furthermore the car would not turn off after killing the ignition...obviously vacuum failure. So my mechanic saw a hose that had come loose and plugged it back in and the car has been good for the last couple days. Then again today, trying to get brakes shortly after starting the car I had to pump it. I'm going to replace the original vacuum pump next week. Is that slow to boost vacuum pressure a pretty good sign that the thing is on the way out? Maybe I shouldn't drive the car at all until I'm able to have the pump replaced. Thanks in advance.

Seth