Causes of the most common failures in hydraulic systems

Hydraulic systems do not require extremely complex work for their maintenance and conservation, since in both cases there are lubricating media that protect their elements and accessories.

Any hydraulic system can be damaged, either by using it at excessive speed, by allowing it to overheat, by raising the pressure too much, or by allowing the fluid to become contaminated.

Correct maintenance will prevent breakdowns or damage. Periodically attend to the system, correcting small problems, avoiding major breakdowns.

The first thing a mechanic must do is diagnose the fault, and then determine if it is due to mechanical, hydraulic or electrical causes.

If a systematic and theoretical check is carried out, the fault can be circled until the point that is believed to be the cause can be controlled.


Noisy pump or motor

• Air intake to intake

• Obstruction in the suction tube

• Suction filter plugged

• Low oil level

• Pump or motor with worn parts

The pump or motor is hot

• Poor cooling

• Cavitation

• Obstruction in the circuit

• Very high pressure

• High turning speed

The pump is not delivering flow or is delivering it poorly

• Broken pump shaft

• Air intake in the suction

• Low oil level

• Direction of rotation reversed

• Filter clogged

• Declined pump

Pump or motor leaks

• Poor tightness of seals and gaskets

• Leaks in the body

• Worn parts

The pump or motor does not turn

• Little flow arrives

• Internal leaks

• Improper loading

• Improper motor or pump

Internal parts breaks

• Excessive working pressure

• Seizure due to lack of fluid

• Abrasives not retained by the filter

The motor turns slower than the flow that reaches it

• Internal leaks

• Low inlet pressure

• Very high temperature

Excessive wear of pumps and motors

• Abrasives or mud in the liquid

• Excess or lack of viscosity

• Very high working pressure

• Misalignment of the pump or motor shaft


Pressure regulating valve

• Regulator does not adjust only to excessive pressure

o Broken spring

o Seized spring

o Worn spring

• Lack of pressure

o Clogged balancing hole

o Clearance in the plunger

o Seized plunger

o Seized spring

o Particles that keep the valve partially open

o Cone or seat worn and / or in poor condition

• System overheating

o Continuous work at discharge pressure

o Oil too viscous

o Leakage from the valve seat

Flow regulating valve

• Regulator does not regulate the flow

o Broken spring

o Regulator stuck

o Defective seat

o Bad state of the non-return valve

• The flow rate varies

o Plunger stuck in valve body

o Oil too dense

o Oil contamination

• Inadequate flow

o Incorrectly adjusted valve

o Restricted valve piston stroke

o Channeling or holes clogged

o Very hot oil

Retention valve

• Leaks

o Joints in poor condition

o Loose connections

o Defective seats

Stuck valve

• Back pressure in drain

• Defective seat

• There is no drainage

Distribution valves

• The dispenser gets hot

o High oil temperature

o Dirty oil

o Seized reel

• Incomplete or defective distribution

o Switch with play or binding

o Insufficient pilot pressure

o Burned or defective electromagnet

o Faulty centering spring

o Plunger or switch misadjustment

• The cylinder extends or retracts slowly

o The distribution piston is not centered properly

o The distribution piston does not move to the stop

o Valve body worn

o Valve seat leaks

• Valve leaks

o Defective gaskets

o Back pressure in the drain

o Scratches on the switch and / or valve seat

o Bad connections

• Seized spool or commutator

o Dirt or contamination in the fluid

o Very viscous oil

o Joints in poor condition

o Scratches


Inadequate filtration

• Filter clogged

• Inadequate filter

• Inadequate maintenance

• Excess dirt in the oil

• As the duct is plugged, the VLP opens and the oil passes through unfiltered



• Pulsating pump flow

• Air in the circuit

• Unstable pressure regulation

• Cavitation

• Badly fixed pipes

Bad tightness

• Gaskets worn or improperly installed

• Loose or loose connectors

• Bad installation

• Pipe with tension

Now that you know the causes of the most common failures, you will be able to identify the problem with the hydraulic system of your machinery faster. Always follow maintenance routines to avoid damage and be able to prevent or detect a failure in time that could delay work.

Almax Seal Solution

Almax Seal Solution


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