maintenance of hydraulic systems

Maintenance of hydraulic systems

It is impossible to over stress the importance of hydraulic system maintenance. In any plant using hydraulic machinery, the smooth operation of all hydraulic systems is essential to ensure work is completed on time. Damaged or broken parts can slow down work or halt it completely, costing your business in lost revenue and the cost of repairs. The easiest way to avoid this is to implement a complete system of Planned Maintenance for all equipment to ensure any damage to parts or unusual performance is spotted as early as possible. Any warning signs can then be acted upon and any issues remedied before major repairs are needed. Damage or poor performance in one part of the system can place extra stress on other parts, leading to further damage down the system.

Reactive maintenance

The first duty of responsibility lies with the user of the equipment. They should be sure that they are familiar with the equipment and trained thoroughly in its operation to prevent any damage through incorrect use. Following this, a few basic checks before use and monitoring the equipment’s performance can spot warning signs of damage. These should be reported by the user immediately and a system for recording any concerns put in place by management. Reacting to these problems as soon as they occur can save time and money and avoid more extensive repairs further down the line from continuing to use damaged equipment.


  • Before use the user should check oil levels and the condition of the oil by means of a dipstick. If the oil level is low it should be topped up immediately, if the oil has a milky or foamy appearance it can be an indication of contamination by moisture or air and the source of the leak should be isolated and repaired and the oil changed.
  • The drive shaft should be checked before use to ensure all components are clean and undamaged and to make sure there are no leaks.
  • When the motor is started, the user should ensure it is running at the correct rpm. If in doubt, check the operator’s manual.


  • Increased temperature – The temperature of the oil should be checked regularly during use, if it is too hot to touch or smells burnt it could be a sign of a damaged cooling system. If the oil is too hot it can degrade and lose its ability to lubricate properly and the increased heat in the system can damage valves and seals.
  • Excessive noise – banging or rattling noises coming from the hydraulic system can be a sign of Cavitation or Aeration as a result of air or water contaminating the hydraulic fluid, leading to a host of internal problems.
  • Erratic performance – Slow hydraulics can be a symptom of reduced flow through the system and a sign of damage to multiple parts. Weak hydraulic response can again be a sign of restricted flow or low pressure caused by leaks in the system.

If any of these warning signs are observed, the equipment should be shut down immediately and a professional company dealing with hydraulic system repairs called in.

Planned Maintenance

With a thorough system of planned maintenance in place, involving regular checks and inspections, large scale plant machinery repairs can often be avoided as any minor problems will be isolated and resolved before they can lead to major damage. As it is recommended that hydraulic fluid should be changed after fifty hours of use, this is a good interval for a thorough check of the whole system.


  • Hydraulic pump –

    This is the heart of the system, using the power of the engine to pump the fluid and maintain flow and pressure. After an external examination for any damage, check all inlet pipes for any kinks or leaks that could affect flow and clean any inlet filters. Check the fluid level and the condition of the fluid for evidence of contaminants. Insufficient fluid can reduce flow and risks airlocks that can cause cavitation where air under pressure in the pump implodes, damaging the interior of the system and dislodging debris. Contaminating particles in the fluid as a result of this can cause scouring and erosion of parts.

  • Cylinders and Motor –

    Cylinders consist of a rod and a housing, both should be checked for any physical damage and the seal where the cylinder exits and enters the housing should be checked for erosion and leaks. Any leaking seals in the cylinder can cause leaking fluid and a loss in pressure and the condition of the fluid should also be checked for contamination. The motor should be checked to ensure it is running at the correct rpm, as per the user manual and the hydraulic oil in the motor should also be checked for contamination to prevent any wear and damage to components.

  • Cooling System and Reservoir –

    The cooling system must be free of debris that could restrict airflow and reduce the cooling of the fluid that has passed through the system. The reservoir that feeds the pump should also be cleared of any debris that has built up and any filters cleaned thoroughly. Overheating of the fluid in the system can reduce the lubricating effect and potentially damage seals and valves , leading to leaking fluid or air entering the system.

  • Valves –

    As noted above contaminants can erode the soft materials in valves or heat can cause degradation, reducing the ability of the valves to maintain a tight seal. This prevents them efficiently directing the flow of fluid, so all valves should be regularly checked for signs of damage or wear.

  • Hoses and lines –

    Hoses and lines can be fragile and easily damaged by general wear and tear or overheating. Cracked or split lines and hoses can leak, reducing pressure within the system and pieces of them could break off and enter the system . Pinched or kinked hoses and lines can also reduce flow and pressure as fluid can’t pass through effectively. All couplings should be inspected for damage and cleanliness as they are one of the most common points of entry for contaminants. Any damaged parts should be immediately replaced.

As long as these checks are performed regularly, the chances of equipment breaking will be significantly reduced and any worn or damaged parts can be replaced before they cause problems for the rest of the system. This will greatly reduce the cost of repairs and ensure a far longer working life for hydraulic systems, which are very costly to replace. Most common hydraulic problems have a simple cause and can easily be spotted and solved if a system of planned maintenance is in place.

If you or your staff need advice on any aspect of hydraulic safety and plant maintenance, call CJ Plant. We have an experienced team of expert staff who will be happy to deal with any queries you may have and can perform any maintenance work needed from hydraulic pump repairs to complete plant machinery repairs. We are experts in mobile plant repairs and provide a UK wide collection service for any damaged equipment. We will then transport it free of charge to our custom built facility where it will be thoroughly inspected and an evaluation and no obligation quote will be offered. We can then repair your equipment to full OEM standards with a twelve month warranty. We also offer a replacement parts service and can even offer new or reconditioned equipment at very competitive prices should yours be beyond repair.

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Tracey Jones

Tracey Jones is the sales & marketing director at CJ Plant Maintenance and has tonnes of experience within this sector. Tracey contributes to the blog, sharing her knowledge and passion for hydraulic repair and plant maintenance.