Test Procedure
WARNING: This page is about a different car, the 2002 Pontiac Sunfire and 2002 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.
- Were you sent here from General Diagnosis? If so, go to next step. If not, go to DIAGNOSTIC STARTING POINT - HYDRAULIC BRAKES under TROUBLE SHOOTING.
- Inspect for proper brake pedal travel. See BRAKE PEDAL TRAVEL under ADJUSTMENTS & INSPECTIONS. Is the brake pedal travel distance within the acceptable limits? If so, go to step 5. If not, go to next step.
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- Inspect for worn, missing, misaligned, bent or damaged brake pedal system components. For the brake pedal pushrod component inspection, see BRAKE PEDAL PUSHROD INSPECTION under ADJUSTMENTS & INSPECTIONS. Inspect the brake pedal bushings for excessive wear and/or damage and inspect the brake pedal for a misaligned, bent and/or damaged condition.
- Replace the brake pedal system components that are worn, missing, misaligned, bent or damaged.
- Reinspect for proper brake pedal travel. See BRAKE PEDAL TRAVEL under ADJUSTMENTS & INSPECTIONS. Is the brake pedal travel distance within the acceptable limits? If so, go to step 8. If not, go to next step.
- Check the engine vacuum source that supplies vacuum to the vacuum brake booster. See BRAKE SYSTEM VACUUM SOURCE TEST under SYSTEM TESTING. Is the vacuum reading within the acceptable limits? If so, go to next step. If not, see appropriate ENGINE article in ENGINE, CLUTCH & DRIVE AXLE.
- During the vacuum source inspection, did the vacuum booster check valve operate properly? If so, go to step 8. If not, go to next step.
- Replace the vacuum booster check valve. See VACUUM BRAKE BOOSTER CHECK VALVE AND/OR HOSE under REMOVAL & INSTALLATION. Did you complete the replacement? If so, go to next step.
- Pump the brake pedal several times until the brake pedal becomes hard. Maintain moderate foot pressure on the brake pedal and start the engine. Observe pedal operation. Did the brake pedal drop slightly, then remain firm after the engine was started? If so, go to next step. If not, go to step 12.
- Release the brake pedal. Turn the ignition OFF, then wait 15 seconds. Pump the brake pedal two times to check for vacuum booster available vacuum reserve. Observe pedal effort. If operating properly, the vacuum brake booster should maintain assist for at least two pedal applications. Did the brake pedal effort increase significantly? If so, go to step 12. If not, go to next step.
- Inspect the brake pedal pushrod and the brake pedal for misalignment, a bent condition and/or damage. Is the brake pedal pushrod and/or the brake pedal misaligned, bent or damaged? If so, go to next step. If not, go to step 13.
- Replace the brake pedal pushrod and/or the brake pedal, as necessary. See BRAKE PEDAL ASSEMBLY and VACUUM BRAKE BOOSTER under REMOVAL & INSTALLATION. Did you complete the replacement? If so, go to step 13.
- Replace the vacuum brake booster. See VACUUM BRAKE BOOSTER under REMOVAL & INSTALLATION. Did you complete the replacement? If so, go to next step.
- Install or connect any components that were removed or disconnected during diagnosis. Did you complete the operation? If so, system is okay.