Hydraulic Pump System Failure Analysis


There are several things that can disrupt a hydraulic system and lead to pump failures.


Any hydraulic system will generate heat, regardless of how it is designed, so making sure the heat is properly handled within the hydraulic system is very important.

This must be done to make sure the oil temperature doesn’t reach a point where it will cause damage to seals or valves.

One key way to make sure there is no excess heat buildup is to use a lubricant reservoir that is of the proper size. A tank that is too small for a hydraulic system can easily overheat and create problems.


Contamination from oil that doesn’t meet the right standard for cleanliness, due to poor filtering, can create two major problems.

It can damage the pump and also result in blockages in the hydraulic system.

This means it’s vital to ensure the hydraulic system has an effective filtration system to cleanse the oil of any problem-generating contaminants. So filters must be changed regularly to keep the fluids clean and the system operating smoothly.


Cavitation is what happens when there is a lack of oil moving through the inlet line from the reservoir tank to the inlet port of the hydraulic system’s pump, or at other points in the system’s lines.

This can cause metal erosion, damaging the pump and contaminating the fluid, and can also reduce the flow of lubricant. In the worst cases, it can trigger mechanical failure of lubrication system components.

One easy to remember way to check for cavitation is to look for any foamy oil moving through the system. If spotted, this is a strong indicator that there may be a cavitation problem in the hydraulic system.

But how can cavitation be prevented, or dealt with if it is occurring?

One technique is to increase the size of the inlet line, which leads from the reservoir tank to the pump.

Another way to deal with cavitation is to reduce the flow in the hydraulic system.

Also, straightening out the inlet line by removing any bends and elbows can also help, in addition to getting rid of any filters placed on the inlet line.

Finally, it’s important to ensure the reservoir tank holding the lubricant oil is position above the pump.


Aeration, like cavitation, is what happens when air enters the lubricant, creating foamy lubricant fluid, as well as erratic actuator movement. Like cavitation, it can even result in abnormal banging or knocking noises from the fluid as it compresses and decompresses.

It speeds up the degradation of the lubricant fluid and can lead to hydraulic system failure that damages components.

Aeration normally gets into the system through the inlet line leading to the pump. Inlet lines can become porous as they get older, while air can also enter into the system through clamps and fittings that are not tightened appropriately.