Hummer H3. Manual — part 1311

BRAKE PEDAL EXCESSIVE TRAVEL

Brake Pedal Excessive Travel

4

Excessively worn or damaged
suspension components

2. Adjust, repair or replace components

as necessary. Refer to Diagnostic
Starting Point - Suspension
General Diagnosis .

Did you find and correct a condition?

Go to Step 6

Go to Step 5

5

1. Inspect the brake assist system for the

following conditions:

Binding, bent or damaged pedal
pushrod, pedal or pedal bracket

Damaged or improperly
operating vacuum booster, if
equipped

Damaged or improperly
operating hydraulic booster, if
equipped

2. Adjust, repair or replace components

as necessary. Refer to Brake Assist
System Diagnosis.

Did you find and correct a condition?

Go to Step 6

Go to
Diagnostic
Starting Point -
Hydraulic
Brakes

6

1. Install or connect components that

were removed or disconnected during
diagnosis.

2. 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

Step

Action

Yes

No

DEFINITION: Brake pedal travels further than expected to obtain firm pedal and/or firm

2007 Hummer H3

2007 BRAKES Hydraulic Brakes - H3

pedal cannot be obtained, pedal fades away or pedal is spongy.

1

Were you sent here from the Hydraulic
Brake Symptom table?

Go to Step 2

Go to
Diagnostic
Starting Point -
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 Step 3

-

1. Inspect the hydraulic brake system for

the conditions listed, based on the
following symptoms observed during
the pedal travel and feel inspections:

Pedal feel was spongy

Air in hydraulic system

External brake fluid leaks

Soft, weak or damaged
hydraulic hoses; expanding

2007 Hummer H3

2007 BRAKES Hydraulic Brakes - H3

3

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

2. Repair or replace components as

necessary. Refer to Hydraulic Brake
System Diagnosis.

3. Re-inspect brake pedal apply travel

and feel.

Did you find and correct a condition?

Go to Step 8

Go to Step 4

1. Inspect the disc brake system for the

2007 Hummer H3

2007 BRAKES Hydraulic Brakes - H3

4

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

2. Adjust, repair or replace components

as necessary. Refer to Disc Brake
System Diagnosis.

3. Re-inspect brake pedal apply travel

and feel.

Did you find and correct a condition?

Go to Step 8

Go to Step 5

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 Step 7

Go to Step 6

1. Inspect for worn, missing, misaligned,

bent or damaged brake pedal system
components.

For the brake pedal pushrod
component inspection, refer to
Brake Pedal Pushrod
Inspection .

Inspect the brake pedal bushings
for binding, excessive wear

2007 Hummer H3

2007 BRAKES Hydraulic Brakes - H3