2005 BMW X5 - weak brakes, mechanical vacuum pump not working

Описание: Testing the vacuum brake booster to determine if the vacuum pump is working or not. Another way to do this (I don’t have the tooling for it), is to tee into the system and run the vehicle to see if it pulls vacuum. If it pull vacuum and holds the booster and pump are both good. If the pedal drop under constant pressure - you likely have a master cylinder leaking internally.