Maintenance and Trouble Shooting of Hydraulic Systems

7/31/2019 Maintenance and Trouble Shooting of Hydraulic Systems

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Standard Maintenance practices Periodic checking of oil level in the reservoir

Periodic cleaning of suction strainer

Return line filter element to be changed after initial 100 hrsand at 500 hrs there after.

Periodic analysis of oil sample for contamination

Flushing of the system after major breakdown and restart

Mounting of magnets in reservoir to prevent entry offerrous particles

Dont return to the system any fluid that has leaked out

Dont mix two different grades / makes of oil


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Standard Maintenance practices Use clean containers, hoses and funnels for filling the oil

into the reservoir. Use of portable filtration unit isrecommended

Use only cloth for cleaning or wiping of hydrauliccomponents

Ensure proper type and quantity of spare items and properstorage


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Sequence of shutting down the machine for

serviceLower or

mechanicallysecure all

suspended loads

Discharge both

ends of theintensifier

Isolate the

electrical powersupply

Isolate the

electrical controlsupply

Drain down allaccumulators

Exhaust anypressure locked

in the system


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What is to be checked?

The Pressure - For Force of the actuator

The Flow - For Speed of the actuator

The Direction of flow - For the direction of theactuator

Ask questions in terms of pressure, flow and control toidentify the problems


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Trouble shooting

Probable Cause Remedy

Wrong direction of pump rotation Run in specified direction of rotation

Pump shaft not rotating Key not fitted or coupling is loose

Large air entry form the suction

port

Tighten all suction fittings, fill with

hydraulic oil or cover with greaseInsufficient revolution Run at least minimum specified RPM

Failure of vanes to come out of slotsin a vane pump

Disassemble, clean and remove dust in slots

Delivery rate set at set at 0 with a

variable displacement pump

Re adjust the delivery rate

High mounting position Height of pump inlet port to be within onemeter from the oil level in reservoir

Excessive oil viscosity Choose oil with suitable viscosity grade

Worn out or damaged parts Repair or replace the parts

No Flow from the pump:


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Trouble shooting


Reservoir fluid level low Top up the Reservoir

Reduced efficiency of oilcooler

Check the temp. of cooling media (Air/ Water)Check for choking of cooling area (Tubes / Fins)Check for quantity of supply of cooling media(Fan angle damage / Water supply)

Correct fluid is not used Drain and refill with correct fluid

The pump output pressure istoo high

Readjust the set pressure of the relief valve to meetwith required system load

Increased internal drain inpump (Wear out)

Measure the drain amount Piston pumpMeasure flow at set pressure Vane pump & Gearpump (volumetric efficiency)

Reservoir surrounding notclear

Clear the area for natural cooling

Excessive Temperature:


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Trouble shooting


Pump noisy Air in the system Tighten all suction fittings, fill withhydraulic oil or cover with grease

Air entry through pump shaft seal Replace the shaft seal if worn out

Air bubbles in the reservoir

Return line pipe should terminate belowoil surface in reservoir at any timeLocation of return pipe with respect tosuction pipe to be proper and also flow path

Small size of the suction strainer(Increased suction flow resistance)

Change to larger size suction strainer

Clogged strainer / Filter (Increasedsuction flow resistance)

Clean or replace the strainer / Filterelement

Pump speed is too high Reduce the pump speed to the rated speed

Coupling misalignment Realign motor and pump accurately

Relief valve noisy Setting too lowor too close to another valve setting Adjust to correct pressure

Excessive Noise:


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Trouble shooting


The line pressure is out ofthe rated pressure range ofthe seals

Check the seal if it meets with the use for the linepressure. If not replace it

Seal is not compatible withoil

Either swelling or shrinkage can occur due to thechemical reaction. Change the seals to theparticular type of oil used

Deformation due to self lifeof seals

Flatness or hardness may change or degradationcan occur since the seals have a specific self life

The finish of the surfacewhich interferes with theseal is improper

Check the surface area for roughness, burrs andcontaminant particles on the areaRefurnish the surface, Get rid of burrs, clean thesurface area

Oil leakage:


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Maintenance and Trouble Shooting of Hydraulic Systems

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