Contents: Wheel cylinders ↓ Brake drums ↓
Wheel cylinders
Check the cleanliness of the working surfaces of the cylinder, pistons and thrust rings. The surfaces must be completely smooth, without roughness, to prevent fluid leakage and premature wear of the seals and pistons. Remove irregularities on the cylinder mirror by lapping or grinding, but an increase in the internal diameter of the cylinder is not allowed.
Check the condition of the stop screw 3 (see fig. 205), spring 6, support cup 7 and crackers 5. If necessary, replace damaged parts with new ones. Replace seals 8. Check the condition of protective caps 10 and replace them if necessary.
Pads. Check the pads carefully for damage or deformation. Check the elasticity of the upper and lower tension springs; replace them with new ones if necessary. The springs should not have any residual deformations when stretched with a force of 35 kgf for the lower springs and 42 kgf for the upper ones. Check the cleanliness of the linings, if dirt or traces of grease are found, clean the linings with a metal brush and wash with white spirit, in addition, check for grease leaks inside the drum; eliminate any faults found. Replace the pads with new ones if the lining thickness has become less than 1.5-2 mm.
Brake drums
Inspect the brake drums. If there are deep scratches or excessive ovality on the working surface, bore the drums and then grind them on a lathe with bars (grain size 10-16). This increases the durability of the linings and improves the uniformity and efficiency of braking. The greatest permissible increase in the nominal diameter of the drum (250 mm) after boring and grinding is 1 mm. This requirement must be met, otherwise the strength of the drum is impaired. The maximum diameter of a worn drum is 251.6 mm.