Chevrolet Silverado / GMC Sierra. Service manual — part 2363

BRAKE PEDAL EXCESSIVE TRAVEL

4

connections

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 (Hydraulic Assist).

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

1

Were you sent here from the Hydraulic Brake
Symptom table?

Go to Diagnostic
Starting Point -
Hydraulic

2008 Chevrolet Silverado 1500

2008 BRAKES Hydraulic Brakes - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

Go to Step 2 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
under pressure

Pedal fell away and/or traveled to or
almost to floor

External brake fluid leaks

Poor brake fluid quality; low
boiling point

2008 Chevrolet Silverado 1500

2008 BRAKES Hydraulic Brakes - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

3

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

following conditions:

Cracked, excessively worn or
damaged linings

Cracked, excessively worn or
damaged rotors

Improperly operating, binding or

2008 Chevrolet Silverado 1500

2008 BRAKES Hydraulic Brakes - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

4

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

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 and/or
damage and inspect the brake pedal
for a misaligned, bent, and/or
damaged condition.

2. 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

2008 Chevrolet Silverado 1500

2008 BRAKES Hydraulic Brakes - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado