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 - Hydraulic Brakes

Visually inspect the disc brake pads for the following conditions. Refer to Brake Pad Inspection in Disc Brakes.

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

Go to Step 3

Go to Step 10

Are any of the front disc brake pads contaminated?

Go to Step 8

Go to Step 4

Are any of the front disc brake pads worn unevenly?

Go to Step 7

Go to Step 5

Are any of the front 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 Brake Pads Replacement in Disc Brakes.

Did you complete the inspection and replacement?

Go to Step 10

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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.

Important: Do NOT disconnect the hydraulic brake flex hoses from the calipers.

1. Remove the front disc brake calipers from the mounting brackets and support the calipers. Refer to Brake Caliper Replacement in Disc Brakes.
2. Inspect the disc brake caliper mounting bracket and the mounting/sliding hardware for the following conditions. Refer to Disc Brake Mounting and Hardware Inspection in Disc Brakes.

•	Binding or seized hardware

•	Worn, damaged or missing hardware components

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

3. Replace the caliper bracket, if necessary. Refer to Brake Caliper Bracket Replacement in Disc Brakes.
4. Replace the unevenly-worn, loose or damaged disc brake pads and/or hardware, if necessary. Refer to Brake Pads Replacement in Disc Brakes.

Did you complete the inspection and replacement?

Go to Step 12

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8

1. Inspect the vehicle for an obvious source of a fluid leak. Repair as necessary.
2. Inspect the disc brake calipers, brake hoses, and brake pipes for evidence of a brake fluid leak.
3. Replace any components found to be leaking brake fluid. Refer to the following procedures:

•	Brake Caliper Overhaul or Brake Caliper Replacement in Disc Brakes

•	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 9

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

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.

Important: Do NOT disconnect the hydraulic brake flex hoses from the calipers.

2. Remove the front disc brake calipers from the mounting brackets and support the calipers. Refer to Brake Caliper Replacement in Disc Brakes.
3. Inspect the disc brake caliper mounting and hardware for the following conditions. Refer to Disc Brake Mounting and Hardware Inspection in Disc Brakes.

•	Binding or seized hardware

•	Distorted, worn, damaged or missing hardware components

4. Replace the caliper hardware components, if necessary. Refer to Disc Brake Hardware Replacement in Disc Brakes.
5. Replace the disc brake pads as a complete axle set. Refer to Brake Pads Replacement in Disc Brakes.

Did you complete the cleaning, inspection and replacement?

Go to Step 10

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10

Visually inspect each of the disc brake rotor shields for evidence of contact with the brake rotors.

Are any of the brake rotor shields contacting the brake rotors?

Go to Step 11

Go to Step 12

Repair or replace the disc brake rotor shields as necessary. Refer to Front Brake Shield Replacement in Disc Brakes.

Did you complete the repair or replacement?

Go to Step 12

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1. Measure the thickness of each of the disc brake rotors.

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 16

13

Important: Perform the following inspection AND ANSWER the question INDIVIDUALLY for EACH rotor.

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

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

Go to Step 15

Go to Step 14

1. Inspect each of the disc brake rotors for the following surface and wear conditions. Refer to Brake Rotor Surface and Wear Inspection in Disc Brakes.

•	Heavy rust and/or pitting

•	Cracks and/or heat spots

•	Excessive blueing discoloration

•	Deep or excessive scoring beyond the 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 on the results of the inspection.

Does the disc brake rotor require for REFINISHING?

Go to Step 15

Go to Step 20

1. Refinish the brake rotor. Refer to Brake Rotor Refinishing in Disc Brakes.
2. Measure 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 20

Go to Step 19

Is the brake rotor at or below the DISCARD requirements?

Go to Step 19

Go to Step 17

17

Important: Perform the following inspection AND ANSWER the question INDIVIDUALLY for EACH rotor.

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

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

Go to Step 19

Go to Step 18

1. Inspect each of the disc brake rotors for the following surface and wear conditions. Refer to Brake Rotor Surface and Wear Inspection in Disc Brakes.

•	Heavy rust and/or pitting

•	Cracks and/or heat spots

•	Excessive blueing discoloration

•	Deep or excessive scoring beyond the 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.

Does the brake rotor require REPLACEMENT?

Go to Step 19

Go to Step 20

Important: Measure the assembled lateral runout (LRO) after replacing the brake rotor in order to ensure optimum performance of the disc brakes.

Replace the brake rotor. Refer to Brake Rotor Replacement in Disc Brakes.

Did you complete the replacement?

Go to Step 20

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20

Important: Perform the following inspection AND ANSWER the question INDIVIDUALLY for EACH rotor.

Inspect each of the disc brake rotors for assembled lateral runout (LRO). Refer to Brake Rotor Assembled Lateral Runout Measurement in Disc Brakes.

Does the brake rotor assembled LRO exceed the maximum acceptable level?

Go to Step 21

Go to Step 22

Correct the brake rotor assembled LRO. Refer to Brake Rotor Assembled Lateral Runout Correction in Disc Brakes.

Did you complete the operation?

Go to Step 22

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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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