Pinpoint Tests
Vibration When Brakes Are Applied
Normal Operation and Fault Conditions
During moderate to heavy braking, noise from the HCU and pulsation in the brake pedal can be observed. Pedal pulsation coupled with noise during heavy braking or on loose gravel, bumps, wet or snowy surfaces is acceptable and indicates correct functioning of the ABS. Pedal pulsation or steering wheel nibble when the brakes are applied (frequency is proportioned to the vehicle speed) indicates a concern with a brake or suspension component.
PINPOINT TEST A : VIBRATION WHEN BRAKES ARE APPLIED
A1 ROAD TEST THE VEHICLE -LIGHT BRAKING
Road test the vehicle. Warm the brakes by slowing the vehicle from 80 to 32 km/h (50 to 20 mph) using light brake force. At highway speeds of 89-97 km/h (55-60 mph), apply the brake using light pedal force.
Is there a vibration/shudder felt in the steering wheel, seat or brake pedal?
Yes | GO to A4 |
|---|---|
No | GO to A2 |
A2 ROAD TEST THE VEHICLE -MODERATE TO HEAVY BRAKING
Road test the vehicle. At highway speeds of 89-97 km/h (55-60 mph), apply the brake using a moderate to heavy pedal force.
Is there a vibration/shudder?
Yes | GO to A3 |
|---|---|
No | The concern is not present at this time. |
A3 CHECK ABS (ANTI-LOCK BRAKE SYSTEM) OPERATION
NOTE: During moderate to heavy braking, noise from the Hydraulic Control Unit (HCU) and pulsation in the brake pedal can be observed. Pedal pulsation coupled with noise during heavy braking or on loose gravel, bumps, wet or snowy surfaces is acceptable and indicates correct operation of the ABS. Pedal pulsation or steering wheel nibble with the frequency proportional to vehicle speed indicates a concern with a brake or suspension component.
Road test the vehicle and apply the brakes on a dry, firm surface, then apply the brakes on a wet, snowy or loose surface (such as gravel).
Is the vibration/shudder only present on a wet, snowy or loose surface?
Yes | This is a normal operating condition of the ABS. |
|---|---|
No | GO to A5 |
A4 ISOLATE BRAKE VIBRATION
NOTE: This test step is not applicable to vehicles with drum-in-hat type or electronic parking brakes. For vehicles with drum-in-hat or electronic parking brakes, proceed to the next test step. For all other vehicles, apply the parking brake to identify if the problem is in the front or rear brake.
2016 Mustang workshop publication supplied to Mustang Atlas. Original technical text and illustrations; HTML formatting by Mustang Atlas. Source page numbering is retained for traceability. Follow the configuration, revision, warnings, and cross-references in the material. About this edition.