BMW 5 Series E39

1. Press a brake pedal at the idle engine not less than 10 times. Then, without releasing a pedal, start the engine. At the same time brake pedal pressure under effort of a leg has to weaken. In this case the vacuum amplifier is serviceable.
2. Otherwise disconnect a vacuum hose from the amplifier and start the engine. Apply a finger to the end of a vacuum hose and check whether there is a vacuum.
3. If there is no vacuum: Check tightness of a vacuum hose and existence of damages. If necessary replace. Tighten all collars.
4. Diesel engine: Disconnect a vacuum hose from the vacuum pump and check a finger vacuum availability.
5. If vacuum is: Measure value of vacuum. If necessary replace the vacuum amplifier (work HUNDRED).

At the same time surely replace the backpressure valve in the vacuum pipeline since the diaphragm in the amplifier can be damaged owing to penetration of vapors of fuel (at the petrol engine and the damaged backpressure valve). Shooters on the backpressure valve have to specify in the direction of the inlet pipeline.