Contents: Wheel and tire ⇊ Braking mechanisms ⇊ Brake pads ⇊ Brake discs ⇊ Wheel hub ⇊ Wheel suspension ⇊ Wheel bearings ⇊ Steering ⇊
Are your brake pads wearing out too quickly? Are your brake discs beating? Don't be too quick to blame the brakes. Often, it is in seemingly extraneous phenomena that one should look for the true reasons for the failure of brake system components.
Wheel and tire
The complete wheel must be perfectly balanced. Make sure there is no radial or lateral runout of either the rim or the tyre. Wheel bolts must only be tightened to the specified torque and in the correct sequence (evenly and crosswise).
Braking mechanisms
Make sure the brake systems are in good general condition. Protective caps must not be damaged. The piston stroke must be flawless, and the guide elements must be in perfect condition (guide bushings, guide bolts, guide planes). The new pads being installed must have good mobility in the caliper guides and mounts.
Brake pads
Use only genuine ATE brake pads (or other approved for use). Select them exactly according to the type of car and the year of its manufacture. Avoid sudden braking for the first 200 km after replacing the pads unless necessary to ensure they undergo a gentle "run-in" period.
Brake discs
The brake discs should be changed simultaneously on the entire axle, taking new ones from the same package. Using a suitable solvent, completely remove the anti-corrosion protection from the disc. The surfaces of the flanges and centering holes must be clean, without burrs or damage. Remember that with ventilated discs the direction of rotation must be taken into account and the balancing brackets must not be removed. Centering must be carried out strictly observing the prescribed torque and the correct tightening sequence. When replacing brake discs, be sure to also replace the pads. If difficulties arise, flange the discs to the specified tightening torque and check the end runout using a dial indicator at a distance of 10 mm from the outer edge of the friction surface. If the runout is too strong, then if possible, move the disc in stages to other positions, checking the runout again.
Wheel hub
The flange area and the centering hole should be sanded until a metallic shine appears. There should be no rust or dirt left on them. They should not be warped or damaged. Lubricating paste should not be applied (including copper). Check the flange area and centering hole for runout and flatness. Keep in mind that hub runout results in twice the disc runout. When flange-fitting the brake disc, observe the recommended torque and the correct tightening sequence.
Wheel suspension
The independent suspension arms should not be deformed, and the silent blocks should not be soft or broken. The rubber bushings of the shock absorbers must be intact, and the shock absorbers themselves (or racks) - in perfect working order. Check that the wheel alignment angles exactly match the manufacturer's requirements.
Wheel bearings
Check the bearing wear. Install, secure and adjust them according to the manufacturer's instructions.
Steering
Check steering components for wear. The steering rod heads must not be broken, and the rods themselves must not be deformed. Steering shock absorber (if it is present on your car) must be in perfect working order.
Braking begins when the pedal is almost to the floor (increased pedal travel):
- Leak in the system;
- Presence of air in the system;
- Jamming of the rear brake automatic adjustment mechanism;
- Damage to the twin metering valve;
- Increased lateral play of the brake disc due to poor seating of the wheel bearings or their wear.
"Swampy" pedal:
- Air in the system;
- Violation of the clearance adjustment between the pads and the drum;
- Clogged vent hole in tank lid;
- Deformation of brake pads;
- Using a liquid with a low boiling point;
- Defects in the disc brake caliper seals.
Insufficient braking efficiency:
- Air in the system;
- Increased clearance between the pads and the drum;
- Oiling of the brake pads or water getting on them;
- Uneven contact of the brake shoes with the drum;
- Brake fluid leak in the system;
- Exposure of the surface of the pads to dirt, oil, grease and water.
- Wear of linings or pads exceeds permissible limit;
- Wear of the main brake cylinder components or the wheel brake cylinder components;
- Brake pedal lever mechanism sticking;
- Boiling of disc brake caliper pistons.
Unbalanced braking:
- Tire pressure variation;
- Damage to linings or pads;
- Damage to the wheel cylinder;
- Wheel bearing misalignment;
- Damage or wear to the drum surface;
- Wear of wheel cylinder elements;
- Loosening of fastening elements of working brake cylinders or brake support disc;
- Wheel alignment is incorrect.
Brake vibration:
- Damage to linings or pads;
- Damage to the drum or disc;
- Oiling of the linings.
"Grabbing" the brake:
- Pedal adjustment failure;
- Damage to the brake drive lever mechanism;
- Master cylinder or wheel cylinder failure;
- Damage to brake pads;
- The parking brake does not release;
- Clogged pipelines or twin metering valve;
- Damage to the brake shoe return springs.
Rear wheel lock:
- Insufficient braking efficiency of the front circuit;
- Excessive wear or abnormal tire pressure;
- Incorrect operation of the twin metering valve (appears when the brake pedal is pressed lightly);
- Local wear on the surface of brake linings;
- Low tire pressure on rear wheels.
Decrease in the liquid level in the absence of traces of leakage in the system elements:
- Leakage from the master cylinder into the vacuum booster of the system;
- Vacuum booster spring failure.
Brake pedal pulsation:
- Brake drum ellipticity or eccentricity;
- Increased lateral runout of the brake disc;
- Uneven thickness of the brake disc.
Spontaneous braking:
- Violation of the adjustment of system elements;
- Breach of the vacuum booster seal.