INSPECTION PROCEDURE 2: Insufficient Braking Power: Diagnosis
- STEP 1. Check that the specified brake fluid is used, its level is correct, and no contamination is found.
Q: Is there fault?
YES: Refill or replace with the specified brake fluid DOT 3 or DOT 4. Bleed the brakes if necessary (Refer to BLEEDING ). Then go to Step 7.
NO: Go to Step 2.
- STEP 2. 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 7.
NO: Go to Step 3.
- STEP 3. Check the brake booster function.
Refer to BRAKE BOOSTER OPERATING TEST .
Q: Is there fault?
YES: Replace the brake booster. Then go to Step 7.
NO: Go to Step 4.
- STEP 4. Check for pinched or restricted brake tube or hose.
Q: Is there a pinched or restricted brake tube or hose?
YES: Replace that complete section of brake tube or brake hose. Then go to Step 7.
NO: Go to Step 5.
- STEP 5. Check for oil, water, etc., on the pad contact surfaces of all brakes.
Q: Is oil, water, etc., on the pad contact surface?
YES: Replace the part. Determine and repair the source/cause of foreign material. Recheck symptom. Then go to Step 7.
NO < Vehicle without ABS >: Go to Step 6.
NO < Vehicle with ABS >: The procedure is complete.
- STEP 6. Check the proportioning valve operation.
Refer to CHECK VALVE OPERATION CHECK .
Q: Is there fault?
YES: Replace the part. Then go to Step 7.
NO: Go to Step 7.
- STEP 7. Recheck symptom.
Q: Is the symptom eliminated?
YES: The procedure is complete.
NO: Start over at step 1. If a new symptom surfaces, refer to the appropriate SYMPTOM CHART .