Failed or malfunctioning brakes are the biggest nightmare of any driver, and keeping your brakes functioning properly is vital (not to mention legally required). However, modern vehicle brakes are complicated and sophisticated equipment, and without proper mechanical knowhow or professional assistance, it can be difficult to detect braking problems by looking at the brakes themselves. Brake pedal problems are a much easier and more noticeable way to determine if your brakes are failing.
One common brake pedal complaint is that the pedal must be pressed very far down before actual braking occurs. This problem can signify a number of issues with your braking system as a whole:
- Low brake fluid levels -- Check your brake fluid reservoir to ensure brake fluid levels meet the fill line.
- Contaminated brake fluid -- Even if your brake fluid levels are optimal, contaminated brake fluid will not provide as much braking power as pure fluid. Brake fluid generally becomes contaminated over time as water seeps into the reservoir through porous rubber hoses and condensation build-up (a particular problem in humid climates), and can also become aerated by any air leaks in your braking system. This can also cause your brake fluid to boil at a lower temperature, potentially causing braking failure under intense driving conditions. Change your brake fluid as often as the manufacturer recommends, and have a professional brake repair service check for pinhole air leaks.
- Brake booster failure -- Many brake boosters rely on the engine's standard intake valves to provide power, but if your brake boosters have a separate vacuum pump attached, pump failure can dramatically increase how far you have to press down your brake pedal. Have a brake repair service inspect your pumps for malfunctions (this requires sophisticated electronic equipment, making it difficult to do yourself) and have faulty pumps replaced.
- Malfunctioning master cylinder -- If your vehicle's master cylinder has failed, your brakes will have little to no pressure, and you may be able to press the pedal all the way to the floor without appreciable braking. Failed master cylinders are very difficult to repair and are generally both cheaper and easier to have replaced entirely.
Push it to the limit
Malfunctioning brakes can also manifest as an excessively stiff brake pedal that can be difficult or impossible to depress effectively. Causes of stiff brake pedals include:
- Brake booster leaks -- If your brake boosters are still functioning but your brake pedal has become stiff, your brake boosters may be leaking. If air is allowed into the vacuum chamber, it will greatly diminish the amount of power a booster can provide. Check for leaks and cracks and have them repaired -- if this does not solve the problem, the booster itself has probably failed and will need to be replaced.
- Clogged or impinged brake lines -- Clogs in the lines that feed brake fluid to the brakes can make braking arduous and can lead to total brake failure if allowed to completely clog the line. Kinked or pinched brake lines can also cause this problem.