Power Brake Troubleshooting

Automotive brake systems use a hydraulic master cylinder that operates a combination of calipers and/or wheel cylinders to apply friction and stop the vehicle. These friction surfaces and pressurized fluid devices can deteriorate over time, and require repair or replacement. The average backyard mechanic can troubleshoot a braking system in about 30 minutes.

Fluid

Inspect the fluid level and condition in the master cylinder reservoir by lifting the cap at the provided tabs. The color should be golden yellow, and the level should be within the operating range on the side of the translucent plastic master cylinder casing. If the fluid is brown or black, and is not full, heat or air could be corrupting the system. Flushing the lines with fresh fluid from this reservoir periodically will prevent pressure issues.

Disc brakes

Inspect the disc braking system for damaged or leaking components by removing the wheel at that brake with a lug wrench and floor jack. The caliper pistons, rotors, and pads all undergo extreme stress and heat under normal operation, and could require replacement. The rotor is susceptible to warping and gouging by heat and debris, the caliper piston has internal seals that could leak fluid, and the padding material is designed to wear down after months or years of use. The rotor is the primary friction surface that stops the vehicle, so be sure this critical part is in good condition.

Drum brakes

Inspect the rear drum brakes, if applicable, by removing the wheel and drum from the hub with a lug wrench and floor jack. Most drums pull free of the brake once the wheel is removed. The shoes and springs inside the brake assembly are hydraulically operated by the wheel cylinder, usually at the top of the assembly. The wheel cylinder can leak through its rubber bushings, and a loss of pressure here can restrict the brake's operation. The shoes should have a good amount of material on them, and the springs should draw the shoes back once the brake pedal is let go. Any malfunction of any of these items can cause dragging, or a loss of braking ability. The shoes and drums should be replaced at regular intervals to prevent failure.