After determining that the shock absorber is faulty or invalid, first check whether the shock absorber is leaking or has traces of old oil leakage.
Situation 1: If the shock absorber does not leak oil, check the shock absorber connecting pin, connecting rod, connecting hole, rubber bushing, etc. for damage, desoldering, cracking or falling off. If the above inspection is normal, the shock absorber should be further disassembled. Check whether the matching clearance between the piston and the cylinder is too large, whether the cylinder is strained, whether the valve is well sealed, whether the valve clack is tightly attached to the valve seat, and whether the extension spring of the shock absorber is too soft or broken. According to the situation, it can be repaired by grinding or replacing parts.
Situation 2: The oil seal washer and sealing washer are broken and damaged, and the oil storage cylinder head nut is loose. It may be that the oil seal and sealing gasket are damaged and invalid. Replace with new seals. If the oil leak cannot be eliminated, the shock absorber should be pulled out. If you feel that there is a hairpin or unevenness, check whether the gap between the piston and the cylinder is too large, whether the piston connecting rod of the shock absorber is bent, and whether the surface of the piston connecting rod and the cylinder tube are scratched or drawn.
Situation 3: In addition, the shock absorber may cause noise in actual use. This is mainly caused by the shock absorber colliding with the leaf spring, the frame or the axle, the rubber pad is damaged or falling off, the shock absorber dust tube is deformed, and the oil is insufficient. The cause should be found out and repaired.