HYDRAULIC UNIT CHECK
CAUTION- The roller of the braking force tester and the tyre should be dry during testing.
- When testing the front brakes, apply the parking brake. When testing the rear brakes, stop the front wheels with chocks.
- Jack up the vehicle. Then support the vehicle with rigid racks at the specified jack-up points or place the front or rear wheels on the rollers of the braking force tester.
- Release the parking brake, and feel the drag force (drag torque) on each road wheel. When using the braking force tester, take a reading of the brake drag force.
- Turn the ignition switch to the "LOCK" (OFF) position and set the MUT-II/III as shown in the illustration.
CAUTION- After checking that the selector lever is in neutral, start the engine.
- Use the MUT-II/III to force-drive the actuator.
NOTE: The ABS system will switch to the MUT-II/III mode and the ABS warning lamp will illuminate.
NOTE: When the ABS has been interrupted by the fail-safe function, the MUT-II/III actuator testing cannot be used.
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- Turn the wheel by hand and check the change in braking force when the brake pedal is depressed. When using the braking force tester, depress the brake pedal until the braking force is at the following values, and check that the braking force changes to the brake drag force inspected in step 2 when the actuator is force-driven. The result should be as shown in the diagram above.
| Front wheel |
785 -
981 N |
| Rear wheel |
588 -
784 N |
- If the result of inspection is abnormal, repair according to the Diagnosis Table below.
| Diagnosis Table |
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|---|---|---|---|---|---|
| MUT-II/III Display |
Operation |
Inspection result |
Judgment |
Probable cause |
Remedy |
| 01 FR VALVE 02 FL VALVE 03 RR VALVE 04 RL VALVE |
|
Brake force is released for three seconds after wheels have been locked. |
Normal |
- |
- |
| Wheel does not lock when brake pedal is depressed. |
Abnormal |
Clogged brake line other than hydraulic unit |
Check and clean brake line |
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| Clogged hydraulic circuit in hydraulic unit |
Replace hydraulic unit assembly |
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| Brake force is not released |
Incorrect hydraulic unit brake tube connection |
Connect correctly |
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| Hydraulic unit solenoid valve not functioning correctly |
Replace hydraulic unit assembly |
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- After inspection, disconnect the MUT-II/III immediately after turning the ignition switch to the "LOCK" (OFF) position.