The main symptoms of malfunctions are the following:
- vehicle pulling to one side during heavy braking;
- increased stopping distance;
- strong screeching when braking;
- brake fluid leaks, usually on the inside of a tire or wheel.
Loosen the wheel bolts.
Raise the vehicle with a jack or lift.
Turn out bolts and remove a wheel.
Disc brakes
As practice shows, the front brake pads on the passenger side wear out more intensively, therefore it is necessary to check the brake pads on the right front wheel.
Loosen the right front wheel bolts and apply the parking brake, then raise the front of the vehicle and secure it on stands. Remove the right front wheel.
Disc brakes have two pads in each caliper. Internal brake pads are visible through viewing windows in each caliper. The outer brake pads are visible on the side of the caliper. Visually determine the thickness of the brake pads.
If it is difficult to visually determine the thickness of the brake pads or there is a suspicion of poor condition of the pads, remove them for further inspection. If the brake pad is worn to a thickness of 1 mm, all four brake pads must be replaced as a set.
Measure the brake disc thickness with a micrometer. If it is less than the limit, replace the disc. Check up a condition of a brake disk on absence of cracks and seizings.
Before installing the wheel, check the condition of the brake hoses and tubes.
Check the condition of the ABS sensor rotor. If damage is found, the hub/rotor assembly must be removed for service.
Install the wheel and lower the car.
Rear drum brakes
Park the vehicle on a firm, level surface.
Place chocks under the front wheels.
Loosen the rear wheel bolts, raise the rear of the vehicle and secure it on stands. Remove rear wheels.
Remove the rear brake drums/hubs.
Warning! Brake pads generate brake dust, which contains asbestos, which is harmful to health, so do not use compressed air or inhale the dust when cleaning brake pads.
Warning! To clean the brake mechanisms, use only a special brake cleaner.
Use a caliper to measure the thickness of the rear brake pads. If the brake pads are 1.0 mm higher than the rivet heads, the brake pads are serviceable, otherwise replace all four brake pads as a set. Brake pads must be replaced if the pad linings are cracked, «licked» or contaminated with brake fluid.
Check the condition of the rear brake return and retaining springs.
Unscrew the protective covers of the working brake cylinders and check for brake fluid leaks. If brake fluid is found under the protective covers, replace the working brake cylinders.
Check the condition of the brake drums for cracks, scratches, deep grooves and burns. If the defects cannot be repaired, replace the brake drums.
Install brake drums.
Install wheels and lower vehicle.
Parking brake
Slowly apply the parking brake with a force of 10 kg, the lever should rise 6-8 clicks. Otherwise, adjust the parking brake.
Park the vehicle on a sloping road, apply the parking brake lever, and move the gearshift lever to the neutral position. If the vehicle is securely held by the parking brake, it is operating normally and properly adjusted.
Vacuum brake booster
The vacuum brake booster reduces the force applied to the brake pedal, thereby making driving easier. The principle of operation of the vacuum brake booster is based on the use of vacuum in the intake manifold. In the event of a failure of the vacuum booster, the performance of the brake system is not impaired, but to press the brake pedal, much more effort must be applied.
Press the brake pedal several times with the engine off to create the same pressure in the cavities of the vacuum booster, close to atmospheric. At the same time, by the force applied to the pedal, determine if the valve body is sticking. Stop the brake pedal in the middle of its travel and start the engine. With a working vacuum booster, the brake pedal should move forward after starting the engine. If the pedal does not move, check the attachment of the hose tip, the connection of the tip flange mounting in the amplifier, the condition of the hose and fitting.