Inspection of the thickness of the friction plate: The thickness of the friction plate (brake shoe lining) is measured with a vernier caliper, the standard value is 4mm, and the use limit is 1.5mm. The surface depth of the rivet and the friction plate shall not be less than 1mm, so as not to scratch the inner surface of the brake drum by the rivet head.
Inspection of the wear and size of the inner hole of the brake drum: first check whether the inner hole of the brake drum is burned, scratched and dented, if it cannot be resharpened, it should be replaced with new parts.
Check the size and roundness error of the inner hole of the brake drum: check the inner hole size with a caliper, the standard value is 180mm, and the use limit is 181mm; Measure the roundness error of the inner hole of the brake drum with a tool, the use limit is 0.03mm, and the new part should be replaced after the limit. Leaning the surface of the brake shoe lining against the rear brake drum, check that the contact area of the two should not be less than 60%, otherwise the lining should be sanded.
Inspection of drum brake positioning springs and return springs: If the free length growth of rear brake positioning springs, upper return springs, lower return springs and wedge adjustment plate springs reaches 5%, new springs should be replaced.
Drum brake adjustment: After the drum brake is assembled, it should be adjusted as necessary to ensure that there is a suitable gap between the brake shoe lining and the brake drum.
1. Erect the axle so that the brake drum can rotate freely;
2. Remove the inspection hole cover on the brake drum;
3. Remove the dust sleeve on the adjustment arm, turn the adjustment cam at the upper end, so that the gap between the brake drum and the brake shoe increases or decreases, after adjustment, it is appropriate to rotate the brake drum when you feel a little resistance. After the gap is adjusted, when there is a slight friction sound, allow the gap to be slightly enlarged.
