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.

Were you sent here from a Brake Symptom table?

Go to Step 2

Go to Diagnostic Starting Point - Vehicle

Visually inspect the disc brake pads for the following conditions:

Refer to Brake Pad Inspection .

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

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

Go to Step 8

Go to Step 4

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

Go to Step 7

Go to Step 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

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 .

Did you complete the inspection and replacement?

Go to Step 12

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Caution: Support the brake calliper 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 calliper in this manner will cause the flexible brake hose to bear the weight of the calliper, which may cause damage to the brake hose and in turn may cause a brake fluid leak.

Note: Do NOT disconnect the hydraulic brake flex hoses from the callipers.

1. Remove the front and/or rear disc brake callipers, as appropriate, from the mounting brackets or from the suspension knuckles and support the callipers. Refer to Front Brake Calliper Replacement and/or Rear Brake Calliper Replacement .
2. Inspect the disc brake calliper mounting bracket and the mounting/sliding hardware for the following conditions:

Refer to Front Disc Brake Mounting and Hardware Inspection and/or Rear Disc Brake Mounting and Hardware Inspection .

•	Binding or seized hardware

•	Worn, damaged or missing hardware components

•	Loose, bent, cracked, or damaged calliper mounting bracket

3. Replace components as required. Refer to the following procedures, as required:

•	Front Brake Calliper Bracket Replacement

•	Rear Brake Calliper Bracket Replacement

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 .

Did you complete the inspection and replacement?

Go to Step 12

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1. Inspect the disc brake callipers, 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:

•	Front Brake Calliper Replacement

•	Rear Brake Calliper Replacement

•	Front Brake Hose Replacement

•	Rear Brake Hose Replacement

•	Brake Pipe Replacement

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.

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 automatic transmission cooling system lines, if equipped, for damage and evidence of an external fluid leak which may be the source of the contamination to the pads.
2. Inspect the power steering system hoses for damage and evidence of an external fluid leak which may be the source of the contamination to the pads.
3. Replace any components found to be leaking fluid which may be the source of the contamination to the pads.

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

Go to Step 11

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

Caution: Support the brake calliper 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 calliper in this manner will cause the flexible brake hose to bear the weight of the calliper, which may cause damage to the brake hose and in turn may cause a brake fluid leak.

Note: Do NOT disconnect the hydraulic brake flex hoses from the callipers.

2. Remove the front and/or rear disc brake callipers, as appropriate, from the mounting brackets and support the callipers. Refer to Front Brake Calliper Replacement and/or Rear Brake Calliper Replacement .
3. Inspect the disc brake calliper mounting/sliding hardware for the following conditions:

Front Disc Brake Mounting and Hardware Inspection and/or Rear Disc Brake Mounting and Hardware Inspection .

•	Binding or seized hardware

•	Distorted, worn, damaged or missing hardware components

4. Replace the calliper mounting/sliding hardware components as required.
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 .

Did you complete the cleaning, inspection and replacement?

Go to Step 12

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12

Visually inspect each of the rear disc brake disc shields/backing plates, if equipped, for evidence of contact with the brake discs.

Are any of the brake disc shields/backing plates contacting the brake discs?

Go to Step 13

Go to Step 14

Repair or replace the disc brake disc shields/backing plates as required. Refer to Front Brake Shield Replacement or Rear Brake Shield Replacement .

Did you complete the repair or replacement?

Go to Step 14

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1. Check the thickness of each of the disc brake discs.

Note: Make the following determination AND ANSWER the question INDIVIDUALLY for EACH disc.

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

Refer to Brake Disc Thickness Measurement .

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

Go to Step 15

Go to Step 18

15

Note: Perform the following inspection AND ANSWER the question INDIVIDUALLY for EACH disc.

Inspect each of the disc brake discs for thickness variation that exceeds the maximum acceptable level. Refer to Brake Disc Thickness Variation Measurement .

Does the brake disc exhibit thickness variation that exceeds the maximum acceptable level?

Go to Step 17

Go to Step 16

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

Refer to Brake Disc Surface and Wear Inspection .

•	Heavy rust and/or pitting

•	Cracks and/or heat spots

•	Excessive blueing discolouration

•	Deep or excessive scoring beyond maximum acceptable level

Note: Make the following determination AND ANSWER the question INDIVIDUALLY for EACH disc.

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

If the brake disc exhibits any of the conditions listed previously, it requires refinishing.

Does the brake disc require REFINISHING?

Go to Step 17

Go to Step 22

1. Refinish the brake disc. Refer to Brake Disc Refinishing .
2. Inspect the brake disc thickness. Refer to Brake Disc Thickness Measurement .

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

Go to Step 22

Go to Step 21

Is the brake disc at or below the DISCARD requirements?

Go to Step 21

Go to Step 19

19

Note: Perform the following inspection AND ANSWER the question INDIVIDUALLY for EACH disc.

Inspect each of the disc brake discs for thickness variation that exceeds the maximum acceptable level. Refer to Brake Disc Thickness Variation Measurement .

Does the brake disc exhibit thickness variation that exceeds the maximum acceptable level?

Go to Step 21

Go to Step 20

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

Refer to Brake Disc Surface and Wear Inspection .

•	Heavy rust and/or pitting

•	Cracks and/or heat spots

•	Excessive blueing discolouration

•	Deep or excessive scoring beyond maximum acceptable level

Note: Make the following determination AND ANSWER the question INDIVIDUALLY for EACH disc.

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

If the brake disc exhibits any of the conditions listed previously, it requires replacement.

Does the brake disc require REPLACEMENT?

Go to Step 21

Go to Step 22

Note: Whenever a brake disc is replaced, the assembled lateral runout (LRO) of the disc must be measured to ensure optimum performance of the disc brakes.

Replace the brake disc. Refer to Front Brake Disc Replacement or Rear Brake Disc Replacement .

Did you complete the replacement?

Go to Step 24

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22

Note: Perform the following inspection AND ANSWER the question INDIVIDUALLY for EACH disc.

Inspect each of the disc brake discs for assembled LRO that exceeds the maximum acceptable level. Refer to Brake Disc Assembled Lateral Runout Measurement .

Does the brake disc exhibit assembled LRO that exceeds the maximum acceptable level?

Go to Step 23

Go to Step 24

Correct the LRO for each brake disc that was determined to have LRO exceeding the maximum acceptable level. Refer to Brake Disc Assembled Lateral Runout Measurement .

Did you complete the operation?

Go to Step 24

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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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