In addition to the specified intervals, the brakes should be inspected every time the wheels are removed or whenever a defect is suspected. Any of the following symptoms could indicate a potential brake system defect: The vehicle pulls to one side when the brake pedal is depressed; the brakes make squealing or dragging noises when applied: brake pedal travel is excessive; the pedal pulsates; or brake fluid leaks, usually onto the inside of the tire or wheel. Disc brakes can be visually checked without removing any parts except the wheels. Remove the hub caps (if applicable) and loosen the wheel lug nuts a quarter turn each. Raise the vehicle and place it securely on jackstands. Remove the wheels. Now visible is the disc brake caliper which contains the pads. There is an outer brake pad and an inner pad. Both must be checked for wear. Measure the thickness of the outer pad at each end of the caliper and the inner pad through the inspection hole in the caliper body. If any brake pad thickness is less than specified, then all brake pads must be replaced. If you're in doubt as to the exact pad thickness or quality, remove them for measurement and further inspection. Check the disc for score marks, wear and burned spots. If any of these conditions exist, the disc should be removed for servicing or replacement. Before installing the wheels, check all the brake lines and hoses for damage, wear, deformation, cracks, corrosion, leakage, bends and twists, particularly in the vicinity of the rubber hoses and calipers. Install the wheels, lower the vehicle and tighten the wheel lug nuts. Sit in the driver's seat and perform the following sequence of tests. With the brake fully depressed, start the engine - the pedal should move down a little when the engine starts. With the engine running, depress the brake pedal several times - the travel distance should not change. Depress the brake, stop the engine and hold the pedal in for about 30 seconds - the pedal should neither sink nor rise. Restart the engine, run it for about a minute and turn it off. Then firmly depress the brake several times - the pedal travel should decrease with each application. If your brakes do not operate as described, the brake booster has failed.
