Inspection Procedure 2
INSPECTION PROCEDURE 2: Insufficient Braking PowerDIAGNOSIS
STEP 1. Check whether the brake fluid is low, is the correct fluid (A/T fluid engine oil, etc.) or is contaminated (debris, sand, etc.).
Q: Is there faucet?
YES: Refill or replace with the specified brake fluid DOT 3 or DOT 4. Bleed the brakes if necessary. Then go to Step 9.
NO: Go to STEP 2.
STEP 2. Check for spongy (not firm brakes).
1. With engine not running, depress the brake pedal rapidly several times to deplete booster vacuum reserve.
2. With the brake pedal fully released, depress the brake pedal slowly until it stops.
3. 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. Then go to Step 9.
NO: Go to Step 3.
STEP 3. Check the lining and brake drum contact (Vehicles equipped with rear drum brake).
1. If equipped with rear disc brake, go to Step 4.
2. Put chalk on the inner surface of the brake drum. Rub the lining against the drum inner surface.
NOTE: Clean off chalk after check.
Q: Does the lining wipe off or smudge the chalk across the full width of the lining?
YES: Go to STEP 5.
NO: Replace the shoe and lining assemblies on both sides. Go to Step 9.
STEP 4. Check the auto adjuster function.
Q: Is there fault?
YES: Repair it. Then go to Step 9.
NO: Go to Step 6.
STEP 5. Check the brake booster function.
Q: Is there fault?
YES: Replace the part. Then go to Step 9.
NO: Go to Step 5.
STEP 6. Check for pinched or restricted brake tube or hose.
Q: Is there pinched or restricted brake tube or hose?
YES: Replace that complete section of brake tube or brake hose. Then go to Step 9.
NO: Go to Step 7.
STEP 7. Check for oil, water, etc., on the pad or lining contact surfaces of all brakes.
Q: Is oil, water, etc., on me pad or lining contact surface?
YES: Replace the part and determine and repair source/cause of foreign material. Recheck symptom. Then go to Step 9.
NO: Diagnosis is complete. If condition persists, go to Step 8.
STEP 8. Check the proportioning valve operation.
Q: Is there fault?
YES: Replace the part. Then go to Step 9.
NO: Go to Step 9.
STEP 9. 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.