General Hydraulic Tips

General Hydraulic Tips

The process of troubleshooting should always begin with checking and eliminating the easy things first. When problems occur with hydraulic equipment, before the expense of hiring a technician is incurred, carry out an informed assessment of the problem and eliminate the obvious.

General Systems

In general, troubleshooting maintenance procedures are for general systems. It is to be noted that an uncomplicated process, such as relocating a system or changing a component part can cause problems. Because of this, the following points should be considered:

  1. Each component in the system must be compatible with and form an integral part of the system, e.g. an inadequate size filter can cause cavitation and subsequent damage to the pump.
  2. All lines must be of proper size and free of restrictive bends. An undersized/restricted line results in pressure drop.
  3. Some components must be mounted in a specific position concerning other components, e.g. the housing of the in-line pump must remain filled with fluid to provide lubrication.
  4. To accelerate troubleshooting, the inclusion of test points for pressure readings is suggested.

Knowing the actual system is the best aid to troubleshooting with confidence. There are some additional practices which increase the ability of the system:

  1. Know the capabilities of the system. Components have maximum rated speed, torque or pressure and loading the system beyond the specifications increases the possibility of failure.
  2. Know the correct operating pressures. It is always advised to check pressures with a gauge.
  3. NOTE: the correct operating pressure is the lowest pressure which will allow adequate performance of the system function and remain below the maximum rating of the components and machine.
  4. Know the proper signal and feedback levels. If they aren’t specified, check when the system is running correctly and mark them on the schematic for reference.


There are three simple maintenance procedures which have the most significant effect on hydraulic system performance, efficiency and life:

  1. Maintain a clean, sufficient quantity of hydraulic fluid of the correct type and viscosity.
  2. Change filters and cleaning strainers.
  3. Keep all connections tight, but not to the point of distortion to allow air to be excluded from the system.

Good assembly practices

  • Cleanliness – the most important but easily forgotten when working on site.
  • Examine pipe fittings and hose assemblies before use to ensure dirt is not present.
  • All openings in the reservoir should be sealed after cleaning.
  • All cylinder, valve, pump and hose connections should be sealed/capped before use.
  • Air hoses can be used to clean fittings and other system components, however, the air supply must be filtered and dry to prevent contamination of the parts.
  • All pipe and tubing ends should be reamed to prevent restriction and turbulent flow.
  • No grinding or welding operations should be done in the area where hydraulic components are being installed.
  • Mineral spirits should be kept in safety containers.
  • Use a dry spray-on lubricant on splines when installing to prevent wear and extend the life cycle of the splines.


The objectives of troubleshooting guides are to provide a logical approach to hydraulic system troubleshooting which can be extended to cover machines in all areas of industry.

Pre-emptive maintenance emphasises the routine detection and correction of root cause conditions that would otherwise lead to equipment failure. In the case of hydraulic systems, three easily detectable symptoms give early warning of root cause conditions. These symptoms are abnormal noise, high fluid temperature and slow operation.

Proactively monitoring noise, fluid temperature and cycle times is an effective way to detect conditions that can lead to costly component failures and unscheduled downtime of hydraulic equipment. In most cases, informed observation is all that is required.

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