I isolated the Master Cylinder (Installed plugs in line Fittings), Engine off, Vehicle had a solid pedal. When I started the engine, the pedal faded away. On the second test I stepped on the brake with the engine running. When the pedal reached the halfway point, I shut the engine off. The pedal stopped dropping. After 1 1/2 minutes of applying pressure, and no pedal fade, I concluded the booster must be bad.
Fortunately, I was right. I've been repairing cars for 30+ years and have never seen a booster fail in this way - a good Tech is always learning!
Tuesday, November 13th, 2007 AT 8:04 PM