Document KGj0yevqZRE7dY04mpz6mRg36

BRAKE SYSTEM DIAGNOSIS AND TESTING LESSON ONE-MODULE 1 Brakes Drag Brake drag is characterized by a steering pull, poor acceleration, and/or poor gas mileage caused by brake activa tion when the pedal is not depressed. These concerns are can be accompanied by an odor concern. Brake drag can be caused by: Binding or sticking brake system components. Misadjusted parking brake mechanism. Power booster push rod misalignment or misadjustment. Trapped hydraulic pressure caused by: - Internal deterioration of brake hoses. - Crimped brake lines and hoses. Brakes Drag Diagnosis To determine the cause of brake drag, perform the following tests: Check for binding or sticking brake components including: - Wheel cylinders. - Drum brake return springs. - Parking brake cables, struts, adjustment mechanisms, and adjustment. - Calipers and caliper slide mechanisms. Check power booster push rod alignment. (If requires adjustment, replace the booster) Check for trapped hydraulic pressure at the affected wheel(s). - Raise vehicle on the hoist. - Determine which wheel(s) are dragging by turning each individual wheel. - Working from the master cylinder to the caliper or wheel cylinder, loosen line and hose connections until the residual pressure is released. Brake System Diagnosis and Repair September, 2005 19