1. Abnormal Power Operation (Highest Percentage)
This is the most common fault encountered on construction sites, mainly manifested as:
The oil pump motor does not work at all after being powered on: This is often due to a damaged microswitch, a loose power plug, or a failed starting capacitor. If the motor makes a humming sound but does not turn, it is generally because the oil pump is stuck by impurities or there is insufficient hydraulic oil, causing it to stall.
The oil pump runs normally, but the cylinder does not move at all: Common causes include insufficient hydraulic oil, the pressure regulating valve being too loose to build pressure, a clogged oil filter blocking the oil circuit, a clogged quick-connect fitting causing pressure relief, or the pressure relief valve not being closed.
The cylinder moves haltingly or erratically: This is mainly due to air mixed in with the hydraulic oil, aging and internal leakage of the cylinder seals, or insufficient oil in the frame guide rail causing it to jam.
2. Abnormal Pressure Parameters
Insufficient system pressure, unable to push the pipes together: After ruling out oil quantity and pressure regulation issues, this is often due to pipe leaks, a stuck overflow valve, or internal leakage caused by wear and tear of the oil pump, resulting in insufficient pressure.
Unstable pressure and frequent pressure drops: Most often caused by impurities stuck inside the relief valve or aging and leaking seals; rarely by a malfunctioning or damaged pressure gauge.
Pressure cannot be released, pressure regulation fails: Generally caused by a stuck or severely worn pressure regulating valve core, leading to malfunction of the pressure regulating function.
3. Oil leakage faults
Oil leakage at quick-connect fittings: Most common, often due to aging and deformation of the gasket or wear of the fitting, resulting in a poor seal.
High-pressure hydraulic hose leakage/bulging: Long-term bending and aging cause damage to the hose body; this is a high-risk fault, and continued use carries the risk of hose bursting.
Oil leakage at the cylinder end cap and piston rod: Caused by wear and aging of the internal oil seal/sealing ring, resulting in seal failure.
Oil leakage at the valve block mating surface: Often caused by aging and failure of the sealant or loose connecting screws.
