Brake Pedal Excessive Effort. Isuzu S/T Isuzu

GM Service Manual Online

For 1990-2009 cars only

Makes 🢒 Isuzu 🢒 1999 🢒 S/T Isuzu - 2WD 🢒 Brakes 🢒 Hydraulic Brakes 🢒 Brake Pedal Excessive Effort

Step

Action

Value(s)

Yes

Did you perform the Hydraulic Brake Diagnostic System Check?

Go to Step 2

Go to Hydraulic Brake Diagnostic System Check

Inspect the brake pedal assembly for the following conditions:

•	Bent or misaligned components

•	Binding or interference between the pedal and booster input rod

Are the components misaligned or binding?

Go to Step 3

Go to Step 4

Repair or replace the cause of misalignment, interference or binding.

Is the repair complete?

Go to Step 13

Inspect the disc brake pads and brake shoe linings for the following conditions:

•	Excessive wear

•	Uneven wear

•

Abuse

•

Glazing

•	Contaminated lining material

•	Incorrect lining material

Refer to Brake Pad Inspection in Disc Brakes or Brake Shoe Inspection in Drum Brakes.

Do any of the above conditions apply?

Go to Step 5

Go to Step 6

Replace the brake linings. Refer to the appropriate procedure:

•	Front Disc Brake Pads Replacement in Disc Brakes

•	Rear Disc Brake Pads Replacement in Disc Brakes

•	Brake Shoe Replacement in Drum Brakes

Is the repair complete?

Go to Step 13

Inspect the brake drums and/or rotors for the following conditions:

•

Hot spots

•	Scored rotor surface

•	Grooved rotor surface

•	Excessive surface variations

Refer to the appropriate procedure:

•	Brake Rotor Thickness Variation Check in Disc Brakes

•	Brake Rotor Lateral Runout Check in Disc Brakes

•	Brake Rotor Tolerance in Disc Brakes

•	Brake Drum Inspection in Drum Brakes.

Do any of the above conditions apply?

Go to Step 7

Go to Step 8

Refinish the brake drums and/or rotors. Refer to Brake Rotor Refinishing in Disc Brakes or Brake Drum Refinishing in Drum Brakes.
Inspect the thickness of the rotor. Refer to Component Specifications in Disc Brakes.
If refinishing the brake rotor results in a thickness that is less than the thinnest (Refinishing) thickness, replace the rotor. Refer to Front Brake Rotor Replacement or Rear Brake Rotor Replacement in Disc Brakes.
Inspect the diameter of the drums. Refer to Component Specifications in Drum Brakes. If refinishing the brake drum results in a diameter that is greater than the maximum (Refinishing) thickness, replace the drum.

Is the repair complete?

Go to Step 13

Inspect the Vacuum Brake Booster and its attaching components for the following conditions:

•

Leaks

•

Damage

•	Restricted passages

Do any of the above conditions apply?

Go to Vacuum Booster Diagnosis - Hard Pedal

Go to Step 9

Inspect the master cylinder outlet ports for restricted passages. Refer to Hydraulic Brake System Bleeding .

Are the outlet ports restricted?

Go to Step 10

Go to Step 11

Overhaul the master cylinder. Refer to Master Cylinder Overhaul .
Flush the hydraulic brake system. Refer to Hydraulic Brake System Flushing .

Is the repair complete?

Go to Step 13

Inspect the brake pipes and hoses for the following conditions:

•	Low fluid or no fluid output

•	Spurting of fluid while pressing the brake pedal

•	Particles suspended in the fluid

Refer to Hydraulic Brake System Flushing .

Do any of the above conditions apply?

Go to Step 12

Go to Step 13

Determine the area of the restriction. This will involve the disassembly of individual brake lines and checking for low or no fluid output.
Flush the individual brake line or hose. Refer to Hydraulic Brake System Flushing .
If the restriction cannot be removed, replace the brake hose or pipe as necessary. Refer to the appropriate procedure:

•	Front Brake Hose Replacement

•	Rear Brake Hose Replacement

•	Brake Pipe Replacement

Flush the hydraulic brake system. Refer to Hydraulic Brake System Flushing .

Is the repair complete?

Go to Step 13

Verify proper brake system operation.

Does the brake system operate properly?

System OK

Go to Hydraulic Brake Diagnostic System Check