Hydraulic Pump Maintenance

Before getting into hydraulic pump  maintenance  and operation, if you’d like a detailed article on hydraulic pumps,  see: Hydraulic pump

The pressure gauges mounted on the suction and pressure lines when starting a hydraulic pump for the first time will be able to show what’s happening in the system. Using pressure gauges, it will be possible to detect any blockage in the pressure line, the pump’s vacuum (suction) capability, or any leaks that may occur in the system.

Pre-Operation Checks for Hydraulic Pump Maintenance

1. You need to check whether the pump’s direction of rotation matches the direction of rotation of the (electric) motor.

2. Make sure the valves on the hydraulic pump‘s suction line are open and the filter is clean. You need to check whether the valves and flow control valves on the pressure line are open.

3. Before starting the hydraulic pump, pour about 1 liter of oil into the pump from the pressure line side. This oil will lubricate the pump, ease the vacuum, and help purge the air.

Important Points in Hydraulic Pump Maintenance

To get the desired performance from the pump being used, the pump manufacturer’s recommendations should be followed.
The hydraulic pump must be installed properly.

Care must be taken to keep things clean when installing the hydraulic pump. The properties of the hydraulic oil to be used should comply with the pump manufacturer’s recommendations and guidelines.

Before using the hydraulic pump, it should be flushed with the oil that will be used, and any protective substances applied during the pump’s assembly should be cleaned off.

The hydraulic pump’s operating pressure and flow rate should be appropriate for the system and operating conditions.

The dimensions of the pipes and hoses used in the circuit should suit the system and should be chosen based on calculation.

All return pipes should be positioned so they extend below the oil level in the tank. Returning fluid should not flow above the oil level.
The diameters of the pipes on the suction and pressure lines should be properly calculated and determined.

All connections and gaskets must provide a seal to prevent air from entering.
The axis of the hydraulic pump shaft and the axis of the electric motor should be aligned with each other.

The pump should never be rotated in the reverse direction.

Before the first startup, the hydraulic pump’s crankcase/housing and the suction line should be filled with oil, and the pump should be prevented from running dry during the first few revolutions. On first startup, the air must be purged from the pipes on the pressure line. Otherwise, the pump will make noise. To purge the air, loosen a fitting on the pressure line and let some oil drain out until foam-free oil comes through.

The reservoir should hold about 3-4 times the hydraulic pump’s flow rate in oil. If a specific oil level is marked, the reservoir should be filled up to that level.

Pressure adjustments should be made while the pump is running at its normal speed. Pressure values should not exceed the values shown in the circuit diagram.
When pressure settings need to be increased, they should be increased gradually.

If the hydraulic pump overheats even though it’s being operated according to the manufacturer’s recommendations, the causes should be investigated.

Minimize the number of elbows and fittings in the hydraulic system. Remember that the shortest distance between two points is a straight line.

A coarse filter (0.3 mm) should be installed on the hydraulic pump’s suction line. The capacity of the filter used should be appropriate. Periodic maintenance should be performed during operation. A periodic maintenance interval of 3 months is recommended for gear pumps, and 6 months for piston pumps

The hydraulic pump’s suction pipe should be straight and short.

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