Can you test the vacuum pump by putting a vacuum on something else that you KNOW isn't leaking? Like, a stopper or plug. Doyt >>>>>>>>>>>>>>>>> At 01:22 PM 9/23/2012, Bob wrote: >I have a 1984 VW Rabbit *diesel*. When I push the brake pedal down, >...snip.... I am >not absolutely sure if the problem is with the servo or the vacuum pump. >Bob Roa