|
Step
|
Action
|
Yes
|
No
|
DEFINITION: Brake pedal travels further than expected to obtain firm pedal and/or firm pedal cannot be obtained, pedal fades away, or pedal is spongy.
|
1
|
Were you sent here from the Hydraulic Brake Symptom table?
|
Go to
|
Go to
Symptoms - Hydraulic Brakes
|
2
|
Inspect the travel and feel of brake pedal applies. Perform the following:
|
1.
|
Apply the brake pedal several times to fully deplete the power reserve.
|
|
2.
|
With power reserve depleted, apply the brake pedal with light, steady pressure and hold for 15 seconds. Observe pedal travel and feel.
|
|
3.
|
Apply the brake pedal with light, steady pressure, then without pumping the pedal, reduce pressure and reapply pressure several times. Observe pedal travel and feel for each apply.
|
|
4.
|
Apply the brake pedal slowly, then release and apply the pedal quickly. Observe pedal travel and feel for each apply.
|
Did you complete the brake pedal travel and feel inspections?
|
Go to
|
-
|
3
|
|
1.
|
Inspect the hydraulic brake system for the conditions listed, based on the following symptoms observed during the pedal travel and feel inspections:
|
|
|
-
|
Air in the hydraulic system
|
|
|
-
|
External brake fluid leaks
|
|
|
-
|
Soft, weak or damaged hydraulic hoses; expanding under pressure
|
|
|
•
|
Pedal fell away and/or traveled to or almost to floor
|
|
|
-
|
External brake fluid leaks
|
|
|
-
|
Poor brake fluid quality; low boiling point
|
|
|
-
|
Internal brake fluid leaks; improperly functioning master cylinder
|
|
|
•
|
Pedal was somewhat firm then dropped slightly, or pedal rose with successive applies, or pedal travel was different between slow and quick applies
|
|
|
-
|
Internal brake fluid leaks; improperly functioning master cylinder
|
|
|
-
|
Poor brake fluid quality; low boiling point
|
|
|
•
|
Pedal returned to rest slowly after any of the applies
|
|
|
-
|
Internally damaged flexible brake hoses; hindering fluid return
|
|
|
-
|
Binding caliper pistons
|
|
|
-
|
Internal brake fluid leaks; improperly functioning master cylinder
|
|
3.
|
Re-inspect brake pedal apply travel and feel.
|
Did you find and correct a condition?
|
Go to
|
Go to
|
4
|
|
1.
|
Inspect the disc brake system for the following conditions.
|
|
|
•
|
Cracked, excessively worn or damaged linings
|
|
|
•
|
Cracked, excessively worn or damaged rotors
|
|
|
•
|
Improperly operating, binding or damaged caliper hardware and/or lining hardware
|
|
|
•
|
Loose or missing caliper hardware and/or lining hardware
|
|
|
•
|
Excessive assembled lateral runout (LRO) of rotor friction surfaces
|
|
|
•
|
Bent or damaged caliper or mounting component
|
|
3.
|
Re-inspect brake pedal apply travel and feel.
|
Did you find and correct a condition?
|
Go to
|
Go to
|
5
|
Inspect for proper brake pedal travel. Refer to
Brake Pedal Travel Measurement and Inspection
.
Is the brake pedal travel distance within the acceptable limits?
|
Go to
|
Go to
|
6
|
|
1.
|
Inspect for worn, missing, misaligned, bent or damaged brake pedal system components.
|
|
2.
|
Inspect the brake pedal bushings for binding, excessive wear and/or damage and inspect the brake pedal for a misaligned, bent, and/or damaged condition.
|
|
3.
|
Replace the brake pedal system components that are worn, missing, misaligned, bent or damaged.
|
Did you find and replace any worn, missing, misaligned, bent or damaged brake pedal system components?
|
Go to
|
Go to
|
7
|
|
1.
|
Inspect the brake assist system for the following conditions.
|
|
|
•
|
Vacuum leaks and/or improperly operating check valve, if equipped with vacuum assist
|
|
|
•
|
Damaged or improperly operating brake booster assembly
|
|
2.
|
Adjust, repair or replace components as necessary.
|
Did you find and correct a condition?
|
Go to
|
Go to
Symptoms - Hydraulic Brakes
|
8
|
|
1.
|
Install or connect any components that were removed or disconnected during diagnosis.
|
Is the condition still present?
|
Go to
|
System OK
|
