Hydraulic Pump Failure and Troubleshooting

Fault	Phenomenon	Reason	Measure
loud noise	Cavitation occurs in pump	Oil suction filter clogged	Clean or replace oil filter
		The diameter of the oil suction pipe is too small	Replace large diameter oil pipe
		There are too many bends in the suction pipe	Rearrange the piping or replace the oil pipe with a larger diameter
		There is a throttling part at the end of the oil suction pipe, such as the pipe is damaged or flattened, or the spring stiffness of the one-way valve is too large	Replace or re-pipe, use a spring with smaller stiffness for the one-way valve
		Oil temperature is too low	Heat oil to recommended operating temperature
		Oil viscosity is too high	Replace hydraulic oil with appropriate viscosity
		Oil bubbles occur	Find out the cause of bubbles and replace hydraulic oil
		Front suction oil supply pump malfunctions	Repair or replace front suction pump
		Pump speed too high	Reduce speed to normal value
		The fuel tank is too tightly closed and has no ventilation holes, causing negative pressure to be generated when absorbing oil.	Install breather with air filter
	Hydraulic oil mixed with air	Inhale air from the sealing part of the moving shaft	Check for damage or wear, replace seal or shaft
		Inhale air from the suction pipe joint	Tighten or replace pipes or joints
		The oil suction hose is made of porous material	Replace hose
		Insufficient oil and air intake	Add enough oil
	mechanical vibration	Shaft connection or coupling is loose	Adjust the connecting part or coupling of the shaft
		Vibration of piping or auxiliary mechanisms	Check and prevent vibrations
	Mechanical vibration of the pump	Worn or poorly installed	Repair, replace or reinstall
		Improper selection of pump form	Choose the appropriate type of pump
Not enough pressure	Pump overheated	The suction pipe sucks in air	Tighten or replace the suction pipe
		Pump is damaged or worn	Repair or replace parts
		Oil viscosity is too low	Replace with appropriate hydraulic oil
		Insufficient cooling device capacity or poor adjustment	Increase or adjust cooling capacity to ensure cooling medium supply
		The local temperature rise of the system is too high	perform local cooling
	Insufficient pump speed or input power	Clutch, pulley or prime mover failure	Repair the faulty area
	Front suction pump system failure	Front suction pump system parts are worn or damaged	Repair or replace
	Problems related to pressure control valves	Control pressure adjustment is too low	Readjust
		Worn or damaged control components	Repair or replace
Abnormal pressure, flow pulsation or vibration	Cavitation occurs in the pump, oil is mixed with air, and mechanical vibration occurs.	See the "loud noise" column
	Pump output pressure pulsation	Improper selection of hydraulic pump form	Re-select a hydraulic pump
	Pressure control valve failure	Control pressure adjustment is too high	Readjust
		Control element wear and damage	Repair or replace
		Unstable pressure control	Disassemble and clean the pressure valve and replace worn parts
Insufficient traffic	Cavitation occurs in the pump and oil is mixed with air	See the "loud noise" column
	Serious internal leakage	Worn or damaged pump or control components	Repair or replace
	Pump speed or input power is insufficient	Refer to the "Insufficient Pressure" column
	Pump reverse	Motor wiring error	Correct wiring
	The variable pump is poorly controlled and has obvious internal leakage.	Poorly adjusted controls	Readjust
external leakage	abnormal pressure	Damaged seal	Eliminate the cause of damage and replace seals
	Parts damaged	Damage to pump casing and other parts	Replacement parts
	Improper installation	The installation direction of the seal is incorrect	Correct installation direction
		Seals damaged during installation	Replace seals
		Insufficient screw tightening force	Increase tightening force

Tags: Hydraulic Pump, Pump Repair, Piston Pump, Spare Parts, Rexroth, Komatsu, Hitachi, Kawasaki