Subject: Automobile Engineering

Topic: Brakes, Steering & Front Axles

Difficulty: Medium

Wheel cylinders in brake system are meant to force the brake shoe against the drum. The construction is very simple. Each cylinder is provided with pistons, rubber seals (Cups), cup spreaders, spring & dust covers. The brake line from the master cylinder is attached to the inlet port & a blender screw with a cover is provided to bleed air from the system whenever required. Wheel cylinders are mounted on back plate.

Working:
When brakes are applied the fluid under pressure from the master cylinder enters the inlet port & forces the pistons to move outward to push the shoe against the drum. Similarly when brakes are released, the brake shoe retractor spring force the brake fluid out of the wheel cylinder by pushing the pistons inward.