Without the use of appliances
Note: if the vacuum booster does not work properly, replace the vacuum brake booster assembly.
1. Checking the operation of the vacuum brake booster.
A) Start the engine.
b) Depress the brake pedal with normal force.
V) While holding the pedal down, stop the engine.
G) Keep the pedal depressed for approximately 30 seconds.
d) If the pedal height has not changed, no vacuum booster malfunctions have been detected.
2. Check for vacuum leaks.
A) Start the engine and let it run at idle speed for approximately 30 seconds.
b) Switch off the ignition and wait 30 seconds.
V) Depress the brake pedal several times with normal force.
G) If the pedal travel is small at the first press, but becomes longer with subsequent presses, no vacuum booster malfunctions have been detected.
Note: If there is a problem, check the vacuum hose or non-return valve and check their installation. If malfunctions are found, eliminate them and once again check the operation of the vacuum brake booster.
3. Check the vacuum hose and check valve.
A) Disconnect the vacuum hose (A) from the vacuum brake booster.
b) Start the engine and set the idle speed.
V) Check for vacuum in the vacuum hose.
If there is no vacuum, replace the vacuum hose with a built-in non-return valve.
If there is vacuum in the vacuum hose, replace the brake booster.
G) Stop the engine and connect the vacuum hose.
Using appliances
1. Vacuum reduction test.
A) Connect vacuum gauge (A), as it shown on the picture.
b) By adjusting the speed of the engine crankshaft with the accelerator pedal, set the vacuum indicated by the vacuum gauge to 66.7 kPa.
G) Shut off the engine and observe the vacuum gauge for 30 seconds. The vacuum should decrease by no more than 2.7 kPa.
- Reduced vacuum - no more than 2.7 kPa (within 30 seconds)
If the decrease in vacuum is not correct, check the following items:
- vacuum hose with check valve;
- vacuum tubes and hoses;
- vacuum brake booster;
- piston rod seal and master cylinder piston collar.
2. Check up pressure in the main brake cylinder.
A) Connect the vacuum gauge as shown.
b) Connect pressure gauges as shown.
V) Download the assembled system.
G) Install a force measuring device on the brake pedal, press the brake pedal with a force of 98 N and read the pressure gauges. Measure the pressure when pressing the brake pedal with a force of 294 N.
d) Start the engine and wait for the engine to warm up - the cooling fan should turn on and off 2 times.
e) By adjusting the speed of the engine crankshaft with the accelerator pedal, set the vacuum indicated by the vacuum gauge to 66.7 kPa.
and) Repeat the measurements described in subparagraph "1".
h) Compare the measured values with those given in the table below.
Right hand drive models before 10/2003
() - 4WD models.
Right hand drive models from 10/2003
Left hand drive models.
() - models with ABS.
If pressure does not correspond to given in the table, check up the main brake cylinder.