General information
Brakes should be tested on a dry, clean, smooth and level road.
1. Perform a brake test at various vehicle speeds, with weak and strong pressure on the brake pedal. However, avoid blocking brakes and slipping tires. Locked brakes and sliding tires are ineffective because sliding friction is always lower than rolling friction under equal conditions. Thus braked but spinning wheels will stop the vehicle within a shorter distance than locked brakes.
Factors that affect braking safety:
- Tires with different grip characteristics will cause uneven braking, so:
- tires must be equally inflated;
- the tread patterns of the right and left tires must be the same;
- loading the car should be as uniform as possible, since more loaded wheels require more braking power;
- misalignment of the wheels, especially excessive camber angle and excessive toe angle of one of the wheels, will cause the vehicle to pull to one side when braking.
2. Check the brake system for leaks. To check for brake fluid leaks, depress and hold your foot firmly on the brake pedal with the engine idling and the speed selector in N (neutral gear). If, with a constant pressure on the pedal, it gradually moves forward, this means that there may be leaks in the hydraulic system, or fluid is bypassed through the cuffs of the main brake cylinder. Perform a visual inspection to confirm any possible brake fluid leaks.
3. If after several consecutive pressings on the pedal, it «rises», that is, the position in which the pedal becomes «tough», becomes higher, this indicates the presence of air in the hydraulic brake system.
4. Check up liquid level in a tank of the main brake cylinder. If a slight drop in the level in the reservoir is the result of normal wear of the friction linings, then a significant drop in level means a leak in the system.
5. In case of violations in the operation of the brakes («low» and/or «soft brake pedal, reduced braking efficiency) the following checks should be made.
- Check for cracks in the master cylinder housing or brake fluid leaks around the master cylinder. Leaks are only taken into account if there is at least one drop of liquid. Wetting of the cylinder surface is considered normal.
- Check the adjustment of the controls (pedals and stem GHC).
- Disassemble the brake master cylinder and check the seals for stretch, swelling or wear.
6. If swollen seals are found, check the brake fluid for contamination. If the brake fluid is found to be contaminated, it is necessary to disassemble and wash all components of the brake master cylinder, and replace all rubber components. In addition, all pipelines must be flushed. Bad brake fluid, mineral oils or water in the fluid can cause the brake fluid to boil or damage rubber parts.
Checking the operation of the brake booster
1. Press the brake pedal several times with the engine off until the pressure in the booster chamber is equal to atmospheric (should «use up» vacuum).
2. Press the pedal and hold it in this position.
3. Start the engine.
4. The booster is OK if the pedal falls further due to the formation of additional force.
5. If the brake pedal does not fail, the vacuum system (vacuum hoses, valve, etc.), may be faulty and should be checked.
6. If no malfunctions are found during the check of the vacuum system, then the malfunction is in the amplifier itself.
Checking the condition of the front disc brake pads
The minimum thickness of the inner or outer friction lining is 7 mm.