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 disc brake
pads?
| Go to
Step 3
| Go to
Step 12
|
3
| Are any of the disc brake pads contaminated?
| Go to
Step 8
| Go to
Step 4
|
4
| Are any of the disc brake pads worn unevenly?
| Go to
Step 7
| Go to
Step 5
|
5
| Are any of the disc brake pads and/or pad hardware loose or damaged?
| Go to
Step 7
| Go to
Step 6
|
6
|
- Remove and inspect the worn disc brake pads for glazing, looseness, heat
spots or damage.
- 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 12
| --
|
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.
- Remove the disc brake calipers, as appropriate, from the steering
knuckles and support the calipers. Do NOT disconnect the hydraulic brake flexible
hoses from the calipers. Refer to
Brake Caliper Replacement
in Disc Brakes.
- Inspect the steering knuckle and the mounting/sliding hardware for the
following conditions:
Refer to
Disc Brake Mounting and Hardware Inspection
in Disc Brakes.
| • | Loose, bent, cracked, or damaged steering knuckle |
| • | Binding or seized hardware |
| • | Worn, damaged or missing hardware components |
- Replace components as required. Refer to the following procedures as required:
- Replace the unevenly-worn, loose or damaged 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 12
| --
|
8
|
- Inspect the disc brake calipers, brake hoses and brake pipes for evidence
of an external brake fluid leak.
- Replace any components found to be leaking brake fluid. Refer to the
following procedures as required:
Did you find and correct the source of the leak causing contamination of the
pads?
| Go to
Step 11
| Go to
Step 9
|
9
|
- Inspect the wheel drive shaft outer seals for damage and evidence of
a grease leak.
- 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
|
- Inspect the following systems for damage and evidence of an external
fluid leak.
- Replace any components found to be leaking fluid which may be the source
of the contamination to the pads.
Refer to the following procedures:
Did you find and correct the source of the leak causing contamination of the
pads?
| Go to
Step 11
| --
|
11
|
- Clean the remaining disc brake system components 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.
- Remove the disc brake calipers, as appropriate, from the steering
knuckles and support the calipers. Do NOT disconnect the hydraulic brake flexible
hoses from the calipers. Refer to
Brake Caliper Replacement
in Disc Brakes.
- Inspect the disc brake caliper mounting/sliding 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 |
- Replace the caliper mounting/sliding hardware components as required.
Refer to
Disc Brake Hardware Replacement
in Disc Brakes.
- Replace the contaminated 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 12
| --
|
12
|
- Check the thickness of each of the disc brake rotors.
Important: Make the following determination AND ANSWER the question INDIVIDUALLY for EACH
rotor.
- 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
|
- 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.
| • | 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.
- Make a determination for each brake rotor if the rotor requires refinishing
based upon the results of the inspection.
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
|
- Refinish the brake rotor. Refer to
Brake Rotor Refinishing
in Disc Brakes.
- 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
|
- 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.
| • | 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.
- Make a determination for each brake rotor if the rotor requires replacement
based upon the results of the inspection.
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
Brake Rotor Replacement
in Disc Brakes.
Did you complete the replacement?
| Go to
Step 18
| --
|
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
| --
|