How do I know if the vacuum pump on my '85 190D is going out? Its slow to develop vacuum at low speed, when I back out of my driveway in the morning I've got no power brakes. By the end of my street like 50 yards away everything is fine.
There is a procedure in the manual for testing it, involving emptying the brake booster and monitoring how long it takes (at idle) to pump back to X Bar. This assumes no leaks.
The vacuum pump is not all that hard to replace on these things, usually. -- Jim
