REAR BRAKE (DRUM) OPERATION
id041100810900
Automatic Adjustment Mechanism
• This brake is equipped with an auto adjust mechanism, which automatically adjusts shoe clearance when the brake pedal is depressed.The auto adjust mechanism is composed of an adjust strut and pawl lever.
When there is large clearance
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• The end of the adjust strut receives the rotation force against the pawl lever caused by the spring which has pin A as its fulcrum.When the brake pedal is depressed, the pawl lever moves in the direction of the arrow with pin A as the fulcrum, because the length of the adjust strut does not change in response to the increase in shoe space.
• The gear rotates because the end B of the pawl lever is engaged with the gear of the adjust strut. Because the gears and the body are engaged by the bolt and nut, the total length of the adjust strut increases when the gear rotates in the direction indicated in the figure. When there is a large clearance, the gear rotates one notch each time the brake pedal is depressed.
When clearance is proper
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• When the clearance is proper, clearance is maintained because the shoe does not stroke (the pawl lever does not tilt) enough at rotate the gear one notch, even when the brake pedal is depressed.
