How to Adjust Drum Brakes?

[StMadeline]

Drum brake adjustment method: Retract the brake shoes to increase the shoe-drum clearance, then perform service braking to achieve the specified shoe-drum clearance. When the push rod travel of the brake chamber becomes excessive due to wear of the brake shoe friction linings, partial adjustment can be made solely via the cam to reduce shoe-drum clearance. Adjustment procedure: 1. First rotate the worm shaft clockwise to eliminate shoe-drum clearance, then rotate counterclockwise until the specified clearance is achieved (typically 3-5 clicks). 2. During partial adjustment, do not loosen the lock nut of the brake shoe pin or alter the camshaft installation position to prevent compromising proper shoe-drum contact. Below are brake shoe maintenance guidelines: 1. Replace brake shoes if cracked or significantly deformed. If lower support pin hole wear exceeds limits (pin hole clearance >0.80mm), repair with bushing; 2. Lining wear should not exceed limits, with no cracks, severe burning or oil contamination; 3. After machining (boring) linings or brake drums, contact area must cover ≥75% of surface.