Wheel Cylinder
Over time, the force applied to wheel cylinders causes them to leak or wear away, which can reduce the reliability and response time of your brakes. As an integral part of the drum brake system, wheel cylinders are most commonly situated directly above each wheel, perpendicular to the direction the wheel travels. Consisting of a small cylinder with a piston on each end, wheel cylinders are at opposite end of the brake line to the brake pedal, so when the pedal is pressed the brake fluid is forced into the cylinders which pushes the pistons out. In turn, the pistons push the brake shoes into contact with the wheel drums, slowing the vehicle through the friction this generates. Older wheel cylinders can eventually split and crack under pressure, while the pistons can be worn down, reducing the force with which the brakes can be applied. Cracks can also result in brake fluid leaks which, as well as being potentially corrosive, can lead to serious hydraulic failure if left unchecked. While most wheel cylinders incorporate two pistons, some designs use two separate, single-piston cylinders, so it’s a good idea to check what you need before ordering your replacements.