Removing
When removing the vacuum booster, do not disconnect the brake master cylinder from the hydraulic system so that air does not get into it. Withdrawal procedure:
- disconnect pusher 14 (see fig. 193) vacuum booster from the pedal;
- unscrew the nuts securing the master cylinder to the amplifier, remove it from the studs 26 and carefully move it aside;
- disconnect the hose from the amplifier;
- Remove the nuts securing the vacuum booster to the clutch and brake pedal bracket and remove the booster.
Installation
Install the amplifier in the reverse order.
Before checking the performance of the vacuum booster, press the brake pedal 5-6 times with the engine off to create in cavities A and E (see fig. 193) the same pressure, close to atmospheric pressure. At the same time, by the force applied to the pedal, determine if there is any jamming of the valve body.
With the brake pedal stopped in the middle of its travel, start the engine. With a working vacuum booster, the brake pedal after starting the engine should «go ahead». If the pedal «does not move forward», check the fastenings of the tip 29, the condition and fastening of the flange 1, the hose to the tip and the engine inlet pipe fitting, since weakening or damage to them sharply reduces the vacuum in cavity A and the efficiency of the amplifier.
In the event of spontaneous braking of the car, check the vacuum booster for leaks with the engine running, first with the brake pedal released and then with the stationary brake pedal pressed. «Suction» protective cap 12 to the shank of the valve body and the hiss of sucked air indicate insufficient tightness of the amplifier.
Even in the absence «suction» protective cap, check the condition of the seal 18, for which:
- carefully remove and then slide the protective cap 12 from the flanging of the hole on the cover 4;
- with the engine off, shake the protruding shank of the valve body in the transverse direction with a force of 3-4 kgf, while the characteristic hiss of air passing inside the amplifier through the seal 18 of the cover should not be heard.
If the vacuum booster is leaking, disconnect the pusher 14 from the brake pedal, remove the protective cap 12 and put 5 g of TsIATIM-221 grease between the seal and the flange of the cover and valve body, then check the condition of the air filter 15, if necessary, replace it and install the protective cap in place. If in this way it is not possible to eliminate air leakage, then replace the vacuum booster with a new one.