48 --- Brakes are spongy or ineffective - disc brakes
Air in brake circuit. This is only likely to happen in service due to neglect in checking the fluid level or because a leak has developed. The problem should be identified and the brake system bled of air
Pad worn. Check the pad wear and renew the pads if necessary.
Contaminated pads. Cleaning pads which have been contaminated with oil, grease or brake fluid is unlikely to prove successful; the pads should be renewed.
Pads glazed. This is usually caused by overheating. The surface of the pads may be roughened using glass-paper or a fine file.
Brake fluid deterioration. A brake which on initial operation is firm but rapidly becomes spongy in use may be failing due to water contamination of the fluid. The fluid should be drained and then the system refilled and bled.
Master cylinder seal failure. Wear or damage of master cylinder internal parts will prevent pressurization of the brake fluid. Overhaul the master cylinder unit.
Caliper seal failure. This will almost certainly be obvious by loss of fluid, a lowering of fluid in the master cylinder reservoir and contamination of the brake pads and caliper. Overhaul the caliper assembly.
Brake pedal improperly adjusted. Adjust the clearance between the pedal and master cylinder to take up lost motion, as recommended in Chapter 9 - Wheels & Brakes.
© April 2014