INSPECTION PROCEDURE 3: Increased Pedal Stroke (Reduced Pedal-to-Floor Board Clearance): Diagnosis
- STEP 1. Check for spongy (not firm brakes).
- With engine not running, depress the brake pedal rapidly several times to deplete booster vacuum reserve.
- With the brake pedal fully released, depress the brake pedal slowly until it stops.
- With a measuring stick (ruler, etc.) next to the brake pedal, depress the pedal firmly and measure the distance the pedal traveled.
Q: Is the distance greater than 20 mm (0.8 inch)?
YES : Bleed the brakes to remove air in the fluid. Refer to BLEEDING . Then go to Step 8.
NO: Go to Step 2.
- STEP 2. Check the pad or lining for wear.
Refer to DISC BRAKE PAD CHECK AND REPLACEMENT or BRAKE LINING THICKNESS CHECK .
Q: Is the pad or lining thickness outside of specifications?
YES : Replace the part. Then go to Step 8.
NO: Go to Step 3.
- STEP 3. Check the vacuum hose and check valve for damage.
Refer to CHECK VALVE OPERATION CHECK .
Q: Is there damage?
YES : Replace the part. Then go to Step 8.
NO: Go to Step 4.
- STEP 4. Check the master cylinder function.
Refer to AUTO ADJUSTER FUNCTION CHECK .
Q: Is there fault?
YES : Repair it. Then go to Step 8.
NO: Go to Step 5.
- STEP 5. Check for brake fluid leaks.
Q: Are there leaks?
YES : Check the connection for looseness, corrosion, etc. Clean and repair as necessary. If leaking in any tube or hose section, replace the complete tube or hose. Then go to Step 8.
NO: Go to Step 6.
- STEP 6. Check the auto adjuster function.
Q: Is there fault?
YES : Repair the part. Then go to Step 8.
NO: Go to Step 7.
- STEP 7. Check the clearance (too much) between the pushrod and primary piston.
Refer to MASTER CYLINDER ASSEMBLY AND BRAKE BOOSTER .
Q: Is the clearance outside of specifications?
YES : Adjust the clearance. Then go to Step 8.
NO: Go to Step 8.
- STEP 8. Recheck symptom.
Q: Is the symptom eliminated?
YES : Diagnosis is complete.
NO: Start over at Step 1. If a new symptom surfaces, refer to the symptom chart.