When your Hydraulic Motors break down, what should you do?

Repair, Rebuild or New hydraulic equipment, but which should you choose?

When hydraulic equipment fails you need to find the quickest way to get up and running as soon as possible, but do you repair, rebuild or buy a new replacement unit? Whether you have one piece of mobile plant or a fleet of large plant machinery, this question arises when a breakdown occurs or when a machine reaches the end of their practical lives.  

A hydraulic pump or motor operating in ideal conditions can last for a very long time. However, it is not always possible to maintain ideal conditions in your system, or the machine will have worked an excessive number of hours, and sooner or later hydraulic pumps and motors will require repair or replacement. But how do you decide when the time has come and what option to take.  To try an minimise being in the position, then regular preventative inspections to your machines and hydraulics, is good practice.  

Often most hydraulic systems are not checked until the operator complains of poor performance, by this time it may be too late to prevent a major failure. Therefore, it is a useful preventative method to ensure your machinery stays in good working order, and to help avoid an untimely and expensive breakdown, is to create a checklist; which should be carried out on a weekly basis and include 


  • Checking Fluid levels.  Add oil (if needed). DO NOT MIX OILS! Use the same oil brand and viscosity grade that is being used in the system.
  • Take Oil Sample – Sampling fluids and looking for any signs of debris or a change of colour or odour. 
  • Visually inspecting caps, filters and screens – Inspect breather caps, breather filters and fill screens, check for wear and blockages 
  • Checking filter indicators and pressure gauges  
  • Visually inspecting all system hoses, pipes and connection. Check for leak and frays.  
  • Checking system temperature – If temperatures are high, check cooler operation and relief valve settings. 

A well-maintained machine will have a longer life span than one which is not, as regular maintenance can prevent many problems. 

Hydraulic pump/ Common cause of failure and how to avoid them

The hydraulic pump is commonly the most expensive component on a hydraulic system and when hydraulic components like pumps, motors, valves and cylinders fail, the overriding goal is to get the system up and running again as soon as possible. One option is simply to purchase and install a new replacement unit, however, a repaired or remanufactured component is often the more economical option. 

Hydraulic pumps have the highest reliability risk. A hydraulic pump failure can be caused by several factors however, there are several tests that can be made on a hydraulic pump to indicate its condition.  

Problems can arise through: 

Leaks –Many hydraulic leaks occur inside the machine, with no exterior signs of a malfunction. However, you may notice decreased performance, sudden drops in pressure, or oil on the outside of the hydraulic unit 

Aeration -Visually inspect inside the hydraulic tank (via the fill hole using a flashlight). Visual signs of aeration, are normally foaming of the oil, also banging and knocking sounds may be heard.  Causes of aeration include: low fluid levels; air leaks in the suction line; low fluid temperature; fluid is too viscous to release air or maintain suction at the pump; or faulty shaft seals.  

Cavitation – Check for unusual sounds, a cavitating pump will emit a high-pitched whine or scream. Cavitation occurs when air is released from the hydraulic oil during momentary depressurization at the pump suction and then imploded onto metal surfaces upon discharge. These implosions are extremely destructive to pump surfaces. 

Filters – Use the correct hydraulic filter, and regularly check for wear or blockages. Clean and upgrade filters on a consistent basis. (Filters that are clogged will stop holding any dirt particles and decrease the life of each component in the hydraulic unit) 

Fluids – Low Quality /Insufficient fluid level. /incorrect Grade. Low fluid levels may result in increased contamination, higher temperatures, and poor oil lubrication. Wrong fluid type or viscosity will affect the system, it will depend upon whether it is running at the correct parameters; a very high fluid viscosity can cause cavitation, while low fluid viscosity can result in inadequate lubrication of components. 

Contamination –Contamination of the hydraulic fluid may occur due to air, water, solid particles, or any other foreign matter. 

  • Air contamination can damage the system through loss of lubrication, overheating, and oxidation of seals. 
  • Water contamination can damage the system components through cavitation and altered fluid viscosity. 
  • Contamination from solid particles can cause abrasive wear. 

Incorrect system design – Incorrectly sized, installed, or adjusted components can create excessive heat and noise, leading to valve wear and oil breakdown. Component wear Other factors that have an impact on component service life include the type of component, circuit design, operating load, duty cycle, and working conditions. 

Excessive temperatures –Overheating is the single most effective way of damaging the hydraulic oil and system components by lowering oil performance and reducing lubrication. 

If your hydraulic machinery should fail, you’ll need fast evaluation & diagnosis to determine whether you should repair, rebuild or buy a replacement unit. Therefore, why not send your unit into a Specialists Hydraulic repair company and let them assess the unit and offer their expert advice. 

At  CJ Plant we are offer hydraulic repair specialists, focussing on the repair, rebuilding or maintenance of hydraulic pumps, motors, final drives, swing boxes, control valve blocks etc. We can support all your needs from the smallest to the largest unit for all different manufacturers.  

Upon receipt of a unit, our expert team of engineers, quickly set about carefully dismantling the unit measuring wear tolerances against manufacturer specifications.  We then offer you a complete evaluation repair and no-obligation quote, to have the part repaired. If a unit is deemed beyond economical repair, then we will quote for a replacement unit. We have an excellent network of suppliers for spare parts to allow us to offer the very best price for repair. Units are then rebuilt to OEM specifications, our investment in our state-of-the-art facilities and equipment enables our customers to have complete confidence that their plant and machinery will be up and running soon after arrival at our facilities. With assurances that our onsite skilled technicians can rebuild, repair and maintain your equipment and plant machinery. Our fast and efficient service, together with our high-quality hydraulic repairs, ensures your machine is up and running again, and in most cases offers significant savings on the cost to replace with new units. 

We can collect a unit if required, (from you free of charge anywhere in the UK) and all repairs come with a written 12-month warranty. 

Get in touch to find out more Call: 01527 535 804

Repair/Rebuild or New? 

  • Repairs are more economical, average savings are up to 60% the cost of new 
  • Average repair time is a week – Replacement Units tend to have a longer lead time 
  • Reputable repair shops warranty all work for 12 months. New units offer between 6 months -12 months.