Brake pedal height
Remove the mat from under the brake pedal.
Measure the height of the pedal position as shown in the figure. If the measured height does not correspond to the nominal value, then the following operations must be performed.
Nominal value: 160-168 mm or more.
Disconnect the brake light switch connector.
Unscrew the pusher locknut and, by rotating the pusher in one direction or another with the help of pliers, adjust the required height of the pedal above the floor.
Tighten the pusher locknut.
Push the brake light switch in the direction of pedal travel as far as it will go. (Switch moves when pressed hard).
Raise the pedal until the pushrod is fully extended, and then move the brake light switch to the desired position. By turning the switch, adjust its position so that the gap corresponds to that shown in the figure.
Connect the switch connector.
Make sure the brake lights do not come on when the brake pedal is not depressed.
Free travel of the brake pedal
With the engine off, press the brake pedal two or three times. After removing the vacuum from the vacuum brake booster, press the pedal by hand and make sure that the movement of the pedal before the start of resistance (free play) is in the optimal range.
Nominal value: 3–8 mm.
If the brake pedal free play exceeds the nominal value, then there is probably an increased clearance in the connection of the brake pedal lever to the pedal mounting bracket. Check clearance and replace damaged parts if necessary.
Distance between brake pedal and floor
Remove the rug, etc. from under the brake pedal.
Start the engine, depress the brake pedal with a force of approximately 490 N, and measure the distance between the brake pedal and the floor.
Rated value: 100 mm or more
If the distance is not within specification, check for air in the brake line, the distance between the brake pads and the drum, and the parking brake.
Adjust or replace defective parts as needed.
Set the mat back in place.
Checking the brake light switch
Connect a universal tester to the brake light switch and check the brake light switch circuit with the pusher pressed and not pressed. If the pusher is pressed so that its length is 4 mm from the end of the housing, then with a working switch, the circuit should be open, and with the pusher not pressed, it should be closed.
Checking the operation of the vacuum brake booster
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A simple check of the operation of the vacuum brake booster is carried out in the manner described below.
Run the engine for one or two minutes and shut it off.
If the first time you press the brake pedal, it is squeezed out to the stop, and with subsequent presses its stroke gradually decreases, then the vacuum booster is working normally. If, with successive pressing of the pedal, its stroke remains unchanged, then the vacuum brake booster is faulty.
With the engine off, press the brake pedal several times. Then, without releasing the pedal, start the engine. If the brake pedal is slightly lowered, then the vacuum booster is working. If, after starting the engine, the pedal remains in place, then the vacuum booster is faulty.
With the engine running, depress the brake pedal and then turn off the engine.
Keep the pedal depressed for 30 seconds. If the position of the pedal does not change, then the vacuum booster is working. If the pedal rises, then the amplifier is faulty. If the results of one of the tests carried out were unsatisfactory, then a malfunction should be sought in the vacuum hose, check valve or brake booster.