Wheel brake cylinder: common defects and their signs

1. Piston jamming.
   • Braking efficiency lowered.
   • Wheels activate non-simultaneously at braking.
   • The braking system reacts slowly to brake pedal pressing.
   • The car deviates from its course when braking.
   • The brake pedal is rigid.
2. Wear out of sealings.
   • The vehicle randomly changes its trajectory after brake pedal pressing.
   • Brake liquid levels in the tank lowering rapidly.
   • Brake pedal pressing takes great effort.

How to repair or replace wheel brake cylinder?

Repair of the wheel brake cylinder consists in replacing all the sleeve gaskets and dust boots. It is important that repair works should be performed only on the component which wasn’t corroded or mechanically damaged. Repair procedure is the following:

1. Connection bolts or wheel nuts should be loosened, then the car body is lifted with the help of a jack; fixations are completely unscrewed and the wheel is demounted.
2. The brake drum should be removed, after it the brake pipe union and brake drum connection bolts are unscrewed. The component is demounted.
3. The component body is fixed in the vice, the dust boot and the retaining ring are removed; then the component is fully disassembled.
4. All the elements are to be cleaned and examined for mechanical damages.
5. If there are no damages, new sealings from the repair kit (purchased beforehand) are installed; the cylinder body is assembled and installed into position.
6. The wheel is mounted into position.

In other cases the defective car component should be replaced. It is recommended to replace wheel brake drums simultaneously on both sides of an axle. The actions are performed in the following order:

1. Remove the wheel and demount the broken cylinder according to the above described algorithm.
2. Install a new component instead of it.
3. Perform assembling in reverse order.
4. Bleed the hydraulic brake drive after installation.

Algorithm of replacement may vary for cars of different brands, please study technical documentation of your vehicle before replacement.

It is advised to perform brake cylinder replacement at a service station.
Check braking liquid during brake cylinder replacement and refill it if necessary.
Average operational lifetime is 100 000–150 000 km.

Types:

1. By mounting side:
   • left;
   • right;
   • all-sides.
2. By mounting axle:
   • for the front axle;
   • for the rear axle.
3. By quantity of the pistons:
   • single-piston;
   • dual-piston.
4. By material:
   • cast iron;
   • aluminum.