Checking the brake booster (Chassis / Brake system / Ford Mondeo 3 2000-2007)

PROCEDURE

With the engine stopped, press the brake pedal several times and then hold it in its most extreme position (to failure).
Now start the engine. The pedal should drop another couple of millimeters. If this did not happen, then there are the following reasons for this:
The reduced pressure hose from the intake manifold to the brake booster is leaking: in this case, be sure to replace the hose and check its connecting flanges.
Defective low pressure hose check valve: To check the valve, disconnect the low pressure hose from the booster and start the engine at idle. If you do not hear rhythmic intake noises, close the free end of the hose with your fingertip. If no vacuum is created in the hose after this, the valve is defective.
The rubber gasket between the brake master cylinder and the brake booster has become porous: remove the brake master cylinder from the booster and change the sealing ring.
The air filter on the hydraulic lifter of the booster is dirty: disconnect the filter from the pressure rod using a wire hook. Install the new filter to the center point and clamp around the pusher at the seat. Make sure that the filter closes around the pusher, otherwise unfiltered air may enter the brake booster.
Defect in amplifier membrane: repair is not possible here. It is necessary to completely get used to the idea of a new amplifier.

The basic design of a two-chamber brake booster.

1 - Push rod (to GTZ),
2 - Pressure spring,
3 - Reduced pressure chamber with vacuum connection,
4 - Membrane with a membrane plate,
5 - Working piston,
6 - Filling piston,
7 - Double valve,
8 - valve body,
9 - Air filter,
10 - Piston connecting rod (from the brake pedal),
11 - valve seat,
12 - Working chamber.

Checking the brake booster

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