Checking the brake booster
To check the vacuum brake booster, start the engine and let it run for one or two minutes, and turn off the engine
After that, press the brake pedal several times with normal force
If the pedal goes down on the first press, but gradually rises on the second and third press, the booster is good.
If the pedal height does not change, the booster is defective.
With the engine off, press the brake pedal several times and check the change in pedal height
After that, press the pedal and start the engine.
If the pedal goes down a little, the amplifier is working.
If the pedal height remains the same, the booster is faulty
With the engine running, press the brake pedal and stop the engine.
Hold the pedal down for thirty seconds.
If the pedal height does not change during this time, the booster is OK. If the pedal rises, the amplifier is faulty
If a malfunction is detected during one of the indicated test methods, you need to check the vacuum hose and amplifier and fix the malfunction.
Vacuum hose valve check
Disconnect the vacuum hose (A) from the vacuum booster
Start the engine and set the idle speed.
A vacuum should appear at the disconnected end of the hose. If there is no vacuum, then the valve is not working.
Replacing the vacuum brake booster
Disconnect the vacuum hose (B) from the brake booster housing (A)
Unscrew the fastening nuts and remove the brake master cylinder
Disconnect the vacuum hose from the booster
Unscrew the four nuts securing the vacuum booster
Remove the vacuum booster (A) from the car
Installation
Before installation, we adjust the length of the vacuum booster rod, then install the gasket on the booster housing.
Standard stem length (A): 108±0.5 mm.
We install the amplifier and tighten the nuts (C) of the fastening with the required tightening torque
Connect the booster rod to the brake pedal by placing the pin (A) and the locking pin (B) on the pin (A).
Before installing the locking pin, apply grease to the pin
Installing the master brake cylinder.
Then we connect the brake pipes to the master cylinder
Connect the vacuum hose to the booster
Pour brake fluid into the expansion tank of the main brake cylinder and bleed the brake hydraulics
Checking the system for brake fluid leaks
Checking I eat the free and working stroke of the brake pedal, if necessary, adjust.