Brake fault diagnosis
Cause | Remedy |
Too much brake pedal free travel | |
Friction linings are completely or partially worn | Replace brake friction linings. |
Failure of one of the braking circuits | Check brake circuits for brake fluid leakage. |
Brake pedal travels far when pressed and springy | |
Air in the brake system | Bleed air from the brakes. |
Too little brake fluid in the reservoir | Top up with new brake fluid. |
Friction brake pads at the rear are heavily worn, the base plate of the pad is adjacent to the spring | Replace friction linings. Use branded friction linings. |
Steam formation. Occurs under heavy load, for example, when driving on a pass | Change the brake fluid. Bleed air from the brakes. |
Slow action of the brakes, the brake pedal must be pressed to failure | |
Pipe leak | Tighten the pipeline connection elements or replace it. |
Damage to the cuff in the master or wheel brake cylinder | Replace cuff. If the cuff in the master cylinder is damaged, replace the internal parts or the cylinder itself. |
Damage to the fixed rubber gasket | Repair the caliper. |
Poor braking effect despite strong pressure on the brake pedal | |
Oiled friction linings | Replace friction linings. |
Unusable or hardened friction lining | Replace friction linings. Use only branded friction linings. |
Faulty brake booster | Check the brake booster. |
Piston jamming | Make sure the caliper moves freely. |
Hydraulic system contamination | Clean and change brake fluid. |
Worn friction linings | Replace friction linings. |
Brakes squeak | |
Worn friction linings | Replace friction linings. |
Often due to atmospheric influences (air humidity) | No action is required if the creak is observed after a long parking of the car in high humidity and does not repeat after the first braking. |
Unsuitable friction lining | Replace friction linings. Use branded friction linings. Coat the base of the pad with anti-squeak paste. |
Brake disc rotates out of parallel with caliper | Check the contact surface of the caliper. |
Dirty wells in the caliper | Clean the caliper wells. |
Incorrect installation of pistons in the rear wheel calipers | Check the 20 degree piston setting. |
Brakes lock up on light braking | |
Non-lubricated friction linings | Replace friction linings. |
Brake engages spontaneously | |
Clogged compensation hole in the brake master cylinder | Clean the master cylinder and replace the internal parts. |
Too small clearance between the control rod and the piston of the main brake cylinder | Check clearance (work in a repair shop). |
Friction linings do not separate from the brake disc, the wheels are hard to turn by hand | |
Corrosion in the caliper cylinders | Repair the caliper, if necessary, replace. |
Uneven pad wear | |
Unsuitable friction lining | Replace brake pads. Use branded friction linings. |
Caliper dirty | Clean the caliper wells. |
Stiff piston stroke | Check piston installation. |
Leakage of the brake system | Check the tightness of the brake system. |
Pulsation of the brake pedal | |
Excessive thickness tolerance or lateral runout of the brake disc | Check runout and tolerance. Modify the brake disc or replace. |
Brake disc does not rotate parallel to caliper | Check the contact surface of the caliper. |
Operation of the anti-lock braking system ABS | No action required, normal |
Vibration brakes | |
Unsuitable friction lining | Replace friction linings. Use only branded friction linings. |
Partial corrosion of the brake disc | Carefully clean the disc with a sanding pad. |
Lateral runout of the brake disc | Repair or replace the brake disc. |
Brake pedal slowly lowers when pressed lightly | |
Malfunction of the main brake cylinder | Replace master brake cylinder. |
Single acting brakes | |
Tire pressure not correct | Check tire pressure and correct. |
Uneven tire wear | Replace worn tires. |
Oiled friction linings | Replace friction linings. |
Wheel suspension or steering failure | Check |
Different types of pads on the same axle | Replace friction linings. Use branded overlays. |
Bad contact of friction linings | Replace friction linings. |
Clogged pipeline | Check the brake pressure of all four brakes. |
Dirty caliper wells | Clean the seating surface and guiding surfaces of the friction linings in the caliper. |
Corrosion in the caliper cylinders | Replace caliper. |
Uneven wear of friction linings | Replace friction linings (both wheels). |
Brakes get hot while driving | |
Clogged compensation hole in the brake master cylinder | Clean the brake master cylinder and replace the internal parts. |
Unsatisfactory idling of the pusher of the main brake cylinder | Check for sufficient clearance between the pedal and pushrod and adjust if necessary. |
Brake piston jamming or stiffness | Restore permeability. |
Clogged brake pipe | Clean the pipes, change the brake fluid. |
Incorrect parking brake adjustment | Correctly adjust. |