Hyundai I20 Wheel Cylinders Available Here. Wheel cylinders are an integral component within a drum brake system. They exerting the necessary force onto the brake shoes. This in turn makes them come in contact with the drums, using the power of friction to aid the vehicle in coming to a safe, reliable stop. Signs of faulty wheel cylinders include leaking brake fluid, poor brake response and a brake pedal that feels abnormally soft when depressing it. A new replacement improves functioning to your vehicle’s brakes by restores the needed pressure and friction for its brake shoes and drums to work together.