Wheel Rim Brake Drum Brake Unit: mm Serial Action No. 1 Change lining 2 Replace the brake drum Turn the angle of 3 replace 20-93 Items to be inspected Judgment Wear of Lining Clearance between the rivet head and lining surface: Max. 0.5 Inner surface wear of brake drum Standard Dimension Repairing Limit 438.2 441.2 Over tolerance of roughness of inner surface of brake drum Repairing limit: 0.2