Maintenance Best Practices for Fluid Power systems 2021-03-17T09:10:33-04:00

Maintenance Best Practices for Fluid Power systems

I am sure today if you have been involved in some form or fashion of maintenance you have heard of, read or been involved in a “Predictive Maintenance” program. I believe we all understand the importance of embracing sound maintenance practices and my point with this article is not to belabor that fact but to share with you a sound plan that could assit in developing a predictive maintenance plan for your plant’s hydraulic systems. The attached list is broken down into recommended, daily, weekly, monthly, semi-annual and annual checkpoints that is intended to give you ideas on how you can begin to develop or enhance your current program.

Remember, if we keep our oil cool, clean and dry we will allow our hydraulic systems to optimize the life of its components. It really boils down to a plan and  the discipline to monitor for wear through the data points.

Step I: Predictive Maintenance Program                              

  1. Evaluate each hydraulic system and determine the designed systems parameters.
    1. Pump flow and pressure capabilities. Ensure all components are properly spec’d to handle these.
    2. Piping, tubing and hose are properly sized for both pressure and velocity.

Step II: Developing a Maintenance Routine                              


Check oil levels in HPU tanks. Do not mix oils

  • Inspect breathers and make sure they are in place and tight.
  • Check air/oil cooler fins for contamination.
  • Check for temperature changes in the oil. Normal is 110 to 140 F.
  • Check systems for water or dirt in the oil.
  • Check all hoses, pipes, and connections for leaks.
  • Check and tighten mounting screws and pipe clamps.
  • Verify pressure gauge readings.
  • Check system relief tank line for heat.
  • Monitor the running noises of pumps and electric motors to identify changes.
  • Listen to the pumps for signs of cavitation.
  • Empty all drip pans.
  • Check for possible leaks in the valve groups by wiping an item clean before inspecting it.
  • Keep surfaces of pipes, components and tanks clean
  • Check with the operators to determine if any service or maintenance is required.
  • Check the service book to see if operators have recorded and problems.

Every six weeks

  • Check air filters.
  • For filters with contamination indicator, replace the filter element when the indicator shows a dirty element.
  • Check for leaks in the piping connections.
  • Clean HPU and check for leaks.
  • While off line, tighten any loosened connections.
  • Replace any fittings or pipes which continue leaking after being tightened. Replace any leaking seals.
  • Check the condition of the hydraulic hoses. Remove dirt buildups.  If the hoses have cracks or if oil seeps between the sleeve and the hose, replace the hose.
  • Check the condition of all hydraulic cylinders. Remove any dirt.  Look for leaks.
  • Tighten pipe clamps, if necessary.
  • Tighten bolts on the pumps, electric motors, valves, etc.
  • Record all maintenance in the service book.

Every six months

  • Oil Samples. Send an oil sample to a reputable oil testing service to check for contaminants and wear.  The oil sample should be analyzed for viscosity, wear metals, particle count and (in hot conditions) the neutralization value
  • Check pre-charge on Accumulators.
    • Optional gage assemblies mounted on each accumulator available
  • Check the service book or online maintence tool. Write down any recurring problems and carry out any requested maintenance recorded in the book.


  • Drain the HPU reservoir and clean the tank.
    • Refer to Detail 3.2
  • Drain the oil into containers for cleaning.
  • When re-filling the reservoir, make sure to filter the new or re-claimed oil using a separate filter unit.
  • Check pump and motor couplings.
  • If the proportional valves require service, notify the manufacturer or a service engineer authorized by that manufacturer to perform maintenance.
  • Check the condition of the hydraulic system by testing all hydraulically actuated components.

This is a general overview. To better understsand how to implement these “Best practices” your maintenance team (or the individuals responsible for maintaining your hdyraulic systems) should be properly trained in hydraulic principles, maintenance and reliability techniques. Next week we will share our thoughts on Training and troubleshooting ”Best Practices”.