The wheel cylinder is part of the brake drum assembly. Its job is to press the brake shoes against the brake drum. This creates the friction needed to slow down. Each time you press the brake pedal, the master brake cylinder transmits hydraulic pressure to the wheel cylinder through the brake fluid in the brake line. The casing of the barrel is made of gray cast iron, and light aluminum is commonly used in newer vehicles.
Brake fluid is capable of absorbing water. If you don't replace your brake fluid, the moisture content causes internal rust that will worsen the cylinder hole leaving a hole. Worn piston seals made of rubber will wear and become brittle with age. A ruptured piston seal allows fluid to leak through the piston. Poor brake response and soft brake pedals are other signs that need to be replaced. A leaking cylinder can reduce the braking ability of a vehicle. There are things you can do to save cylinders. Getting recommended service and maintenance and replacement of brake fluid can extend the life of your wheel cylinder. Unfortunately, because the cylinders are hydraulic components that are susceptible to heat and other strains on the brakes, they will eventually need to be replaced. We cannot emphasize the importance of brakes too much.
