1998 Chevrolet K1500 Pickup 4WD - Brake Master Cylinder

Symptoms of a bad brake master cylinder

The brake master cylinder pressurizes and transfers hydraulic fluid in the brake lines to activate your brake calipers and wheel cylinders when pressure is applied to the brake pedal. This creates a pressurized force strong enough to engage the brakes and slow or stop your vehicle. Brake master cylinders often include the brake fluid reservoir, which allows you to inspect the brake fluid level and condition and refill your brake fluid during repairs or service. Over time, the fluid seals inside the master cylinder may wear out. This can lead to a loss of brake fluid near the master cylinder, pulsing or a lack of resistance in the brake pedal, and a reduction or loss of braking pressure. Master cylinder leaks may not even be visible in some cases, but leaks from the rear of the master cylinder can allow brake fluid into the power brake booster and destroy its internal vacuum diaphragm. This may lead to vacuum leaks which could affect performance, and may even cause your vehicle to stall when the brakes are used. If your vehicle is leaking brake fluid, has weak braking pressure, or the brake pedal has no pressure and can easily reach the floorboard when braking, it is best to avoid driving your vehicle until you can inspect the braking system and make your master cylinder repair. If you need a brake master cylinder, brake caliper, or other brake hydraulics, O'Reilly Auto Parts carries the right parts for your next brake repair. You can also learn more about how to bleed your brakes with our How-To Hub resources.