Is it okay to manually adjust automatic slack adjusters?

Key Guidelines for Manually Adjusting the Automatic Slack Adjuster

1. When is Operation Permitted?

• Only in two scenarios:

After replacing new brake pads: The push rod must be retracted to its initial position (called a reset operation).
When mechanically stuck: When the adjuster is stuck due to internal rust, it needs to be unlocked to restore mobility (not a complete adjustment).

2. Situations Absolutely Prohibited

Regular wear compensation: The automatic mechanism is designed for real-time self-adaptation; manual intervention will disrupt the calibration logic.
When braking is weak: If the pedal travel becomes longer, it indicates a system malfunction (such as air leakage in the air chamber), and adjusting the adjuster will be ineffective.

3. Correct Reset Procedure (Must be done after pad replacement)

•Locating the Reset Hole

Locate the dedicated hexagonal hole at the end of the adjuster (usually with a rubber stopper).

•Inserting the Original Tool

Use the specified size hexagonal wrench (commonly 8/10mm); do not use an adjustable wrench.

•Unidirectional Rotation

Rotate clockwise 90°~180° until noticeable resistance is felt (stop when you hear a "click").

•System Activation

After reinstalling the wheel, continuously press the brake pedal 5 times to allow the automatic mechanism to rebuild the reference slack.

4. Unlocking Method for Stuck Devices (Non-Adjustment)

• Mild Rust Treatment: Drip turbine oil into the reset hole to dissolve the rust.
Lightly turn the tool: Turn counterclockwise 30° → Reset clockwise → Repeat 3 times.
• Severe Condition Handling: If it cannot be turned, immediately stop using it and replace the adjuster.

5. Disastrous Consequences of Manual Adjustment

• Adjusting Bolt Trap

If the side adjusting bolt is accidentally tightened → ratchet engagement misalignment → permanent loss of automatic compensation function.

• Chain Reaction

Incorrect adjustment → Abnormal pushrod travel
↓ Brake drag (high wheel hub temperature) or braking delay
↓ Premature brake pad/drum failure

6. Emergency Handling Principles