Brake discs: common defects and their signs

1. Wear out.
   • Disc thickness is lower than acceptable.
   • The brake pedal is vibrating during braking.
   • Lines on the disc, caused by the brake pads work, are noticeable; cracks, shears, rust appeared.
   • The discs got extremely hot.
   • Brake pedal clearance enlarged.
   • Screeching and rattling sounds are heard at the pedal pressing.
2. Deformation.
   • Deviation of the car from the set trajectory at braking.
   • Notable wobbling of the steering wheel and the brake pedal at pressing.
   • Screeching and foreign sounds from the wheel area which are heard at braking.
   • Locking of brakes which appears at the brake pedal pressing.

How to repair or replace brake discs?

In case of insignificant wear out the brake discs can be repaired. Component turning is performed in order to repair them. The essence of it is in the following: disc overlayer is grinded down with the help of special equipment, thus its surface becomes smooth again. But you should remember that this method is applicable only for those discs with the residual thickness no lower than acceptable. Component turning should be performed only at the service station by experienced specialists because it takes special skills and appropriate equipment.

In case the disc cannot be repaired due to wear level or the nature of the defect, it is to be replaced. You should remember that the brake discs are to be replaced in pairs on one axle. New brake pads should be installed concurrently with disc replacement. This procedure is simple so you can perform it by yourself. Replacement process can differ according to construction features of different brands vehicles; generally the replacement algorithm of the brake disc is the following:

1. Secure the car in a stationary position with the help of wheel chocks. Then you should unscrew the wheel bolts, lift the car body with the help of a jack and demount the wheel.
2. Then you should pull the slave cylinder piston down.
3. Then you should clean surface of the brake caliper and hub, unscrewing bolts which fixate the brake disc to the hub afterwards.
4. After this you should remove the brake caliper and disassemble the caliper unit: demount brake pads, hold-down springs and the caliper bracket.
5. Then you should remove the defective brake disc, install a new component in its position and assemble elements in reverse order.