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What to Check if Your Hydraulic System is Not Working

A hydraulic system is made up of components that facilitate hydraulic power – which is the power generated from the liquid being pressurised and moved to other components of the system. The pressurised liquid is used to transmit power to different components in other areas of the system, powering them.  

The smooth running of a hydraulic system is dependent on a lot of different things – such as hydraulic liquid, a clean system and appropriate work environments. As a result, many things can go wrong within a hydraulic system. 

This article gives an overview of some of a hydraulic system’s many malfunctions and the potential reasons. 


Identifying Problems with Your Hydraulic System


If your machine is making irregular noises, then this can usually be remedied



Grinding has two main causes: 

  • Contamination – Hydraulic fluid can become contaminated. Metal particles, dirt or other debris can get into the system and cause heavy abrasions to vital components, such as pumps and actuators.
  • Pump Issues – A worn and/or damaged pump can also cause grinding noises from things other than contamination. This can be anything from damage through standard wear and tear, or the hydraulic fluid has lost the lubrication necessary to avoid heavy friction. 



Whining has two main causes:

  • Aeration – When air enters the system and mixes with hydraulic fluid, a chemical reaction named “aeration” occurs. This causes bubbles within the fluid, and that causes a whining as the fluid becomes pressurised. The whining is not the only problem this causes as the efficiency of the fluid’s functions will be reduced, which can lead to a great deal of problems – such as lack of lubrication causing rapid wear and tear.
  • Cavitation – When the hydraulic fluid drops below the “vapour pressure”, then cavities will form within the vapour. When they inevitably collapse, they will cause shock waves throughout the fluid, and that manifests as the whining noise. Aside from the annoyance, cavitation is actually very damaging to the system, as it causes pitting and erosion within the major components. 



Banging has two main causes: 

  • Pressure Spikes – Sudden changes in the hydraulic pressure of your system can lead to banging sounds. Spikes in pressure occur when the system’s flow is blocked, or if the flow changes direction rapidly. The cause of this is due to abrupt stopping of cylinders, or valves that close too quickly. 
  • Shock Loads – Hydraulic systems are designed to handle very specific loads and ranges of pressure, so when they are overloaded, a shock load occurs. This results in banging, of course, but the bigger issue is the fact that the system is struggling and potentially being damaged while being asked to handle more than it is supposed to.

Slow/Inconsistent Movement

If the movement of your machine is slow, or if it ranges between fast and slow, then the following may be wrong with your vehicle. 

Hydraulic Fluid Levels

Low levels of movement in your machine may be a result of your hydraulic fluid levels not being high enough. Insufficient fluid levels result in lower pressure, which means the machine is not strong enough to facilitate its movements at an acceptable pace. 

Block Filters or Lines

Hydraulic systems can suffer from blockages in the system in areas such as the filters and lines. Check and clean these areas out to resume efficient operation. 

Worn Components

Some key components, which consist of pumps, valves and actuators, can wear out over time. When this happens, slower movement is inevitable, and the only way to restore capabilities is to replace the worn components. 

Fluid Leaks

Fluid leaks result in the vehicle being inoperable or highly inefficient. Aside from needing to refill the fluid, you need to also find the source of the leak, and fully repair it. 

Seal or Hose Failure

Seals are responsible for keeping the machine airtight and contain the fluid within. Over time, these can fail due to wear, poor installation quality or the degradation of materials due to exposure to unfit environments. 

Component Cracks 

Hydraulic components can develop cracks through use. This may be an indication of a wider problem, such as contamination. Nonetheless, check the components and patch them.

Loose Connections 

Connections may come loose due to heavy use or increased levels of vibration within the vehicle. 


Components being overheated are a huge problem. If you detect overheating, then one of the following may be the problem. 

Excessive Use or Load 

Using or loading machines beyond their intended parameters can cause irreversible damage through overheating. 

Inadequate Cooling 

All hydraulic systems have cooling mechanisms within, such as the heat exchanger. If something goes wrong with these components, then the system’s cooling is compromised. 

Incorrect Fluid Viscosity

If the viscosity of the fluid is too low, then it may not lubricate the system adequately enough to prevent heavy friction. Friction, of course, generated heat. But it’s also a problem if the fluid is too high in viscosity, because that will result in the system being unable to move the liquid properly. The increased effort of the machine will then, similarly, lead to overheating. 

If you are experiencing any problems with your hydraulic system, it is always prudent to bring in the experts. While you may be able to do some initial fault finding, engaging the expertise of a company such as CJ Plant will ensure you avoid expensive damage to your equipment and downtime is minimised. 

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