Each time you depress your brake pedal, calipers close around your wheels' rotors to create friction that brings your car safely to a halt. Virtually all passenger car brake systems use hydraulic fluid to transmit the force necessary for stopping. A vital component known as the master cylinder converts your brake pedal's movement into hydraulic force.
As time goes on, the master cylinder experiences a lot of pressure-related wear and tear, which eventually leads to failure. Unfortunately, many car owners struggle to identify the signs of master cylinder problems. This article takes a closer look at three poor braking symptoms that may stem from a failing or faulty master cylinder.
1. Spongy or Unresponsive Brake Pedal
Few brake problems cause as much stress as a brake pedal that doesn't produce the desired stopping power. A spongy or unresponsive pedal reduces the effectiveness of your brakes. In extreme cases, your brake pedal may even sink all the way to the floor without producing any appreciable effect.
This nerve-wracking problem usually stems from a leak in your brake fluid system. Leaks may occur in a variety of places, including the master cylinder itself. Inside of a master cylinder resides a piston. When you depress your brake pedal, a connecting rod pushes on the piston, increasing the pressure acting on the hydraulic fluid. This pressure increase causes your calipers to close.
A master cylinder with an internal leak struggles to achieve the necessary hydraulic pressure. Instead of pushing on the calipers, the brake fluid leaks backwards around the rubber seals protecting the piston. Degraded seals often lie at the heart of this issue.
2. Contaminated Fluid
As the seals inside of your master cylinder wear out, the rubber crumbles and degrades, often resulting in visual contamination of the brake fluid. For instance, you may notice the presence of small black flecks inside your fluid reservoir. If such contamination stems from disintegration of the master cylinder seals, you will likely experience a spongy brake pedal as well.
Seals naturally break down over time. That said, you can prolong the lifespan of your master cylinder's seals by always using the manufacturer recommended brake fluid. Likewise, have your brake fluid replaced every 20,000 miles. Fresh brake fluid resists heat build-up better than old fluid, thus minimizing the amount of stress placed on your seals and other components.
3. Brake Drag
Brake drag occurs when your brake pads fail to release the rotor when you raise your foot from the brake pedal. Drag may stem from either mechanical or hydraulic issues. Mechanical issues include misaligned or corroded brake calipers, improperly installed wheel bearings, or incorrect push rod sizing.
On the hydraulic side of things, brake drag may stem from excessive heat, faulty flex hoses, or problems with the master cylinder piston. Under normal circumstances, when you release the brake pedal, the piston moves back to its resting position. This movement lowers the amount of pressure acting on the fluid, allowing the calipers to open back up.
Yet if a piston has become damaged or misshapen, it may not move smoothly inside of the cylinder. As a result, your brake calipers may not release in sync with your brake pedal. In this case, the only solution involves replacing the master cylinder.
Brake drag may also stem from a master cylinder containing an excessive amount of brake fluid. The master cylinder contains a special reservoir used to house the fluid that flows back in when you release the brake pedal. Yet if the cylinder has too much fluid, this reservoir won't have the space to accommodate the influx. As a result, the calipers remain under pressure and fail to release entirely.
The master cylinder has a key role to play in regulating the performance of your brakes. For more information about keeping your master cylinder in good working order, please contact our auto repair experts at Walnut Creek Import Service and Sales.