| DEFINITION: Brake system does not fully release or has delayed release; vehicle motion may be hindered by brake system without applying brakes. |
| 1 |
Were you sent here from the Hydraulic Brake Symptom table? |
Go to Step 2 |
Go to Diagnostic Starting Point - Hydraulic Brakes |
| 2 |
Is the vehicle equipped with an adjustable stop lamp switch and/or an adjustable cruise control release switch? |
Go to Step 3 |
Go to Step 4 |
| 3 |
- Inspect the stop lamp switch for proper adjustment to ensure that the brake pedal is fully releasing.
- Inspect the cruise control release switch, if equipped, for proper adjustment to ensure that the brake pedal is fully releasing.
Did you find and correct a condition? |
Go to Step 14 |
Go to Step 4 |
| 4 |
Is the vehicle equipped with a drum-in-rotor type of park brake system? |
Go to Step 5 |
Go to Step 7 |
| 5 |
Ensure the park brake shoes are not adjusted too tightly, possibly causing drag under certain conditions.
Are the park brake shoes adjusted too tightly? |
Go to Step 6 |
Go to Step 8 |
| 6 |
- Clean and inspect the park brake shoes for excessive wear and/or damage.
- Inspect the drum portion of the rotors for excessive wear, blueing discoloration and heat spots.
- If any of these conditions are present, replace the affected components.
- Adjust the park brake system.
Did you find and correct a condition? |
Go to Step 15 |
Go to Step 8 |
| 7 |
- Inspect the drum brake system, if equipped, for the following conditions.
- Improper adjustment
- Weak or damaged return spring or springs
- Distorted or damaged linings
- Out of round or damaged drum
- Weak or damaged hold down spring or springs
- Lack of lubrication on backing plate
- Distorted or damaged backing plate
- Adjust, repair or replace components as necessary. Refer to Drum Brake System Diagnosis .
Did you find and correct a condition? |
Go to Step 15 |
Go to Step 8 |
| 8 |
Inspect the park brake system for proper operation. Refer to Park Brake System Diagnosis
.
Did you find and correct a condition? |
Go to Step 15 |
Go to Step 9 |
| 9 |
- Inspect the disc brake system for the following conditions.
- Binding, incorrectly installed or missing caliper hardware and/or lining hardware; ensure free movement of linings and of caliper, if equipped with sliding type caliper
- Lack of lubrication or excessive corrosion on metal to metal contact surfaces
- Distorted or damaged linings
- Damaged or excessively worn caliper hardware and/or lining hardware
- Bent or damaged caliper or mounting component
- Adjust, repair or replace components as necessary. Refer to Disc Brake System Diagnosis .
Did you find and correct a condition? |
Go to Step 15 |
Go to Step 10 |
| 10 |
- Separate the brake booster pushrod from the brake pedal.
- Inspect the brake corners to determine if the brake drag condition is still present.
Do the brake corners still exhibit the brake drag condition? |
Go to Step 12 |
Go to Step 11 |
| 11 |
- Inspect the pushrod for improper positioning and/or damage. Correctly position or replace the pushrod if necessary.
- Inspect the brake pedal assembly for damage and replace if necessary.
Did you complete the repair or replacement? |
Go to Step 15 |
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| 12 |
- For vacuum boost systems, disconnect the vacuum check valve from the booster to relieve vacuum reserve.
- Separate the master cylinder from the brake booster. Do not disconnect any brake pipes.
- Inspect the brake corners to determine if the brake drag condition is still present.
Do the brake corners still exhibit the brake drag condition? |
Go to Step 14 |
Go to Step 13 |
| 13 |
Replace the brake booster assembly.
Did you complete the replacement? |
Go to Step 15 |
- |
| 14 |
- Inspect the hydraulic brake system for the following conditions.
- Improper operation of wheel cylinder pistons, if equipped
- Improper operation of caliper pistons
- Contaminated brake fluid
- Internally damaged flexible brake hoses; hindering brake release
- Damaged or improperly operating master cylinder
- Adjust, repair or replace components as necessary. Refer to Hydraulic Brake System Diagnosis .
Did you find and correct a condition? |
Go to Step 15 |
Go to Diagnostic Starting Point - Hydraulic Brakes |
| 15 |
- Install or connect components that were removed or disconnected during diagnosis.
- Road test the vehicle in order to confirm proper operation. Refer to Brake System Vehicle Road Test .
Is the condition still present? |
Go to Step 2 |
System OK |