GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2002 🢒 Alero Export 🢒 Brakes 🢒 Park Brake 🢒 Disc Brake System Diagnosis

Test Description

The numbers below refer to the step numbers on the diagnostic table:

  1. Lubricant leaks from non-brake system components may come in contact with and contaminate brake system components.

    2.

  2. Lubricant leaks from non-brake system components may come in contact with and contaminate brake system components.

Step

Action

Yes

No

DEFINITION: This diagnostic table is designed to diagnose ONLY the components of the DISC brake system in order to determine if the DISC brake system is operating properly. You will be directed by the appropriate Symptom table to go to other brake system diagnostic tables as appropriate.

1

Were you sent here from a Brake Symptom table?

Go to Step 2

Go to Diagnostic Starting Point - Hydraulic Brakes

2

Visually inspect the disc brake pads for the following conditions:

    • Lining thickness below specifications
    • Uneven and/or abnormal wear - edge-to-edge and/or side-to-side
    • Evidence of contamination from an external substance
    • Looseness or damage - including pad hardware

Did you find any conditions to indicate a concern with any of the front and/or rear disc brake pads?

Go to Step 3

Go to Step 12

3

Are any of the front and/or rear disc brake pads contaminated?

Go to Step 8

Go to Step 4

4

Are any of the front and/or rear disc brake pads worn unevenly?

Go to Step 7

Go to Step 5

5

Are any of the front and/or rear disc brake pads and/or pad hardware loose or damaged?

Go to Step 7

Go to Step 6

6
  1. Remove and inspect the worn disc brake pads for glazing, looseness, heat spots or damage.
  2. Replace the worn disc brake pads as a complete axle set. Refer to Front Disc Brake Pads Replacement and/or Rear Disc Brake Pads Replacement , if equipped, in Disc Brakes.

Did you complete the inspection and replacement?

Go to Step 12

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7

    Notice: Support the brake caliper with heavy mechanic wire, or equivalent, whenever it is separated from its mount and the hydraulic flexible brake hose is still connected. Failure to support the caliper in this manner will cause the flexible brake hose to bear the weight of the caliper, which may cause damage to the brake hose and in turn may cause a brake fluid leak.

  1. Remove the front and/or rear disc brake calipers, as appropriate, from the mounting brackets and support the calipers. Do NOT disconnect the hydraulic brake flex hoses from the calipers. Refer to Front Brake Caliper Replacement and/or Rear Brake Caliper Replacement , if equipped, in Disc Brakes.
  2. Inspect the disc brake caliper mounting bracket and the mounting/sliding hardware for the following conditions:

    3. Refer to Front Disc Brake Mounting and Hardware Inspection and/or Rear Disc Brake Mounting and Hardware Inspection , if equipped, in Disc Brakes.

    • Loose, bent, cracked, or damaged caliper mounting bracket
    • Binding or seized hardware
    • Worn, damaged or missing hardware components
  3. Replace components as required. Refer to the following procedures in Disc Brakes, as required:
  4. Replace the unevenly-worn, loose or damaged disc brake pads as a complete axle set. Refer to Front Disc Brake Pads Replacement and/or Rear Disc Brake Pads Replacement , if equipped, in Disc Brakes.

Did you complete the inspection and replacement?

Go to Step 12

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8
  1. Inspect the disc brake calipers, brake hoses and brake pipes for evidence of an external brake fluid leak.
  2. Replace any components found to be leaking brake fluid. Refer to the following procedures as required:
    3. •  Rear Brake Caliper Overhaul or Rear Brake Caliper Replacement , if equipped, in Disc Brakes

Did you find and correct the source of the leak causing contamination of the pads?

Go to Step 11

Go to Step 9

9

  1. Inspect the wheel drive shaft outer seals for damage and evidence of a grease leak.
  2. Replace any wheel drive shaft seal that is found to be leaking grease which may be the source of the contamination to the pads. Refer to Wheel Drive Shaft Outer Joint and Boot Replacement in Wheel Drive Shafts.

Did you find and correct the source of the leak causing contamination of the pads?

Go to Step 11

Go to Step 10

10

  1. Inspect the following systems for damage and evidence of an external fluid leak.
  2. Replace any components found to be leaking fluid which may be the source of the contamination to the pads. Refer to the following procedures:
    3. •  Diagnostic Starting Point - Engine Mechanical in Engine Mechanical - 2.2L
    •  Diagnostic Starting Point - Engine Mechanical in Engine Mechanical - 3.4L
    •  Diagnostic Starting Point - Automatic Transmission in Automatic Transaxle - 4T40-E/4T45-E

Did you find and correct the source of the leak causing contamination of the pads?

Go to Step 11

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11
  1. Clean the remaining disc brake system components to remove any traces of the contaminant.

    2. Notice: Support the brake caliper with heavy mechanic wire, or equivalent, whenever it is separated from its mount and the hydraulic flexible brake hose is still connected. Failure to support the caliper in this manner will cause the flexible brake hose to bear the weight of the caliper, which may cause damage to the brake hose and in turn may cause a brake fluid leak.

  2. Remove the front and/or rear disc brake calipers, as appropriate, from the mounting brackets and support the calipers. Do NOT disconnect the hydraulic brake flex hoses from the calipers. Refer to Front Brake Caliper Replacement and/or Rear Brake Caliper Replacement , if equipped, in Disc Brakes.
  3. Inspect the disc brake caliper mounting/sliding hardware for the following conditions:

    4. Refer to Front Disc Brake Mounting and Hardware Inspection and/or Rear Disc Brake Mounting and Hardware Inspection , if equipped, in Disc Brakes.

    • Binding or seized hardware
    • Distorted, worn, damaged or missing hardware components
  4. Replace the caliper mounting/sliding hardware components as required. Refer to Front Disc Brake Hardware Replacement and/or Rear Disc Brake Hardware Replacement , if equipped, in Disc Brakes.
  5. Replace the contaminated disc brake pads as a complete axle set. Refer to Front Disc Brake Pads Replacement and/or Rear Disc Brake Pads Replacement , if equipped, in Disc Brakes.

Did you complete the cleaning, inspection and replacement?

Go to Step 12

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12
  1. Check the thickness of each of the disc brake rotors.

    2. Important: Make the following determination AND ANSWER the question INDIVIDUALLY for EACH rotor.

  2. Make a determination for each brake rotor if the rotor can be REFINISHED and REMAIN ABOVE the minimum requirements.

Refer to Brake Rotor Thickness Measurement in Disc Brakes.

Does the disc brake rotor meet the minimum requirements for REFINISHING?

Go to Step 13

Go to Step 15

13
  1. Inspect each of the disc brake rotors for the following surface and wear conditions:

    2. Refer to Brake Rotor Surface and Wear Inspection in Disc Brakes.

    • Braking Surface Conditions
       - Heavy rust and/or pitting
       - Cracks and/or heat spots
       - Excessive blueing discoloration
    • Braking Surface Wear Conditions
       - Deep or excessive scoring beyond maximum acceptable level
       - Lateral runout beyond maximum acceptable level
       - Thickness variation beyond maximum acceptable level

    Important: Make the following determination AND ANSWER the question INDIVIDUALLY for EACH rotor.

  2. Make a determination for each brake rotor if the rotor requires refinishing based upon the results of the inspection.

    3. If the brake rotor exhibits any of the following conditions, it requires refinishing.

    • Rotor exhibits one or more of the Braking Surface Conditions listed previously
    • Rotor is beyond the acceptable level in one or more of the Braking Surface Wear Conditions listed previously

Does the brake rotor require REFINISHING?

Go to Step 14

Go to Step 18

14
  1. Refinish the brake rotor. Refer to Brake Rotor Refinishing in Disc Brakes.
  2. Inspect the brake rotor thickness. Refer to Brake Rotor Thickness Measurement in Disc Brakes.

Were you able to REFINISH the brake rotor within the minimum requirements?

Go to Step 18

Go to Step 17

15

Is the brake rotor at or below the DISCARD requirements?

Go to Step 17

Go to Step 16

16
  1. Inspect each of the disc brake rotors for the following surface and wear conditions:

    2. Refer to Brake Rotor Surface and Wear Inspection in Disc Brakes.

    • Braking Surface Conditions
       - Heavy rust and/or pitting
       - Cracks and/or heat spots
       - Excessive blueing discoloration
    • Braking Surface Wear Conditions
       - Deep or excessive scoring beyond maximum acceptable level
       - Lateral runout beyond maximum acceptable level
       - Thickness variation beyond maximum acceptable level

    Important: Make the following determination AND ANSWER the question INDIVIDUALLY for EACH rotor.

  2. Make a determination for each brake rotor if the rotor requires replacement based upon the results of the inspection.

    3. If a brake rotor exhibits any of the following conditions, it requires replacement.

    • Rotor exhibits one or more of the Braking Surface Conditions listed previously
    • Rotor is beyond the acceptable level in one or more of the Braking Surface Wear Conditions listed previously

Does the brake rotor require REPLACEMENT?

Go to Step 17

Go to Step 18

17

Replace the brake rotor. Refer to Front Brake Rotor Replacement , or Rear Brake Rotor Replacement , if equipped, in Disc Brakes.

Did you complete the replacement?

Go to Step 18

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18

Install or connect components that were removed or disconnected during diagnosis.

Did you complete the operation?

Disc Brake System OK

Return to Symptom Table

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