Removal and installation
Note:
- Removal is carried out in accordance with the relevant figure "Removing the vacuum brake booster".
- Install in the reverse order of removal.
- The tightening torques are indicated in the text.
- After installation, check and adjust the brake pedal.
Checking the vacuum brake booster
1. Depress the brake pedal several times with the engine off and check that the pedal travel does not change.
2. Press the brake pedal and start the engine. If the brake pedal smoothly goes down, then the vacuum booster is operational.
3. Check the airtightness of the vacuum booster.
A) Start the engine and stop after one or two minutes of operation. Slowly press the brake pedal several times.
If the pedal drops lower on the first press than on the second and third, the vacuum booster is sealed.
b) Depress the brake pedal with the engine running and stop it with the pedal depressed. If the distance between the floor and the depressed pedal does not change within thirty seconds, the vacuum booster is sealed.
4. Check with pressure gauges.
A) Connect pressure gauges and vacuum gauge as shown and bleed air from system.
b) Check tightness.
Start the engine. Stop the engine when the vacuum is approximately 500 mmHg. Art. (66.7 kPa).
After stopping the engine for 15 seconds, the vacuum does not drop
V) Check tightness without load.
Start the engine and press the brake pedal with a force of 200 N. Stop the engine when the vacuum is approximately 500 mm Hg. Art. (66.7 kPa).
After stopping the engine for 15 seconds, the drop in vacuum will be no more than 25 mm Hg. Art. (3.3 kPa)
G) Checking with the amplifier off.
Stop the engine. Make sure there is no vacuum. Check if the brake fluid pressure is within the allowable values for brake pedal force of 98 N and 294 N (see table "Permissible values of brake fluid pressure with the engine off").
Table. Permissible brake fluid pressure values when the amplifier is off.
Removing the vacuum brake booster.
1 - clamp,
2 - vacuum hose,
3 - fork,
4 - locknut,
5 - fastening nut,
6 - vacuum brake booster,
7 - gasket.
d) Checking the operation of the amplifier. Start the engine. Create a vacuum of 500 mmHg. Art. (66 kPa) Check the pressure at different brake pedal pressures (see table "Permissible values of brake fluid pressure with the engine running").
Table. Permissible values of brake fluid pressure with the engine running.