Hi,
I have a 82 diesel vanagon and I've been having problem with the power break system. When the engine is cold, I get absolutely no assistance from the power break, so it's quite hard to stop the vehicule. After driving it for a while, I start getting some assistance and the pedal gets softer on the driver. However, if I depress the brakes several times, the brake pedal gets hard again, as if the vacuum pump could not supply enough vacuum (diesel engine here). Brake booster looks fine (air thigh) as the brake pedal works properly after the van has been parked for a few days (assuming the brake were ok when parked of course).
Any idea on what could cause this?
Thanks
Sam