Product News09/11/2021

Simple Checks to Make Sure Your Hydraulic Pumps are Operational

Industrial Machinery Of Hydraulic Pump
Industrial Machinery Of Hydraulic Pump

This article aims to provide guidance on building an effective hydraulic system, with advice on selecting a motor and compatible pump for the application.

Converting mechanical power into hydraulic energy, hydraulic pumps are necessary for all hydraulic drives. Many different types of pumps exist to assist fluid movement in a variety of systems; they are prolific in heavy industry, used in their millions worldwide.

The purpose of this month’s article is to provide some blanket information covering what to do, and not to do, in the event that a hydraulic pump needs to be checked. Of course, general checks are vital and need to be scheduled regularly, but there may be a system issue that requires troubleshooting. We hope that this short piece points you in the right direction, although a disclaimer if we may, the purpose of this article is not to provide specific advice on any specific hydraulic pumps. Always read the safety manuals for your product, and contact us if you have any queries.


Diagnosing a faulty hydraulic pump

Before we get stuck into the checks, we think it’s important that we discuss diagnostics; more particularly, how can you diagnose a faulty hydraulic pump? What signs are there when a hydraulic pump may not be working to its optimum capabilities? Let’s explore this, first.

Increased heat

The hydraulic pump may increase in temperature as a result of its decrease in performance. This will be noticeable through a simple touch test, although in extreme cases, it may be visually noticeable through a discharge of steam from the pump.

Along with leaks, overheating ranks highly amongst the most common hydraulic equipment problems. Heating of hydraulic fluid in operation is caused by inefficiencies. Inefficiencies result in losses of input power, which are converted to heat.

Louder or different noise

We all know that hydraulic pumps make noise regardless, and if the kit is running smoothly then that noise will continue at its usual rate. There will be no cause for concern.

That said, you may begin to notice that something isn’t working to peak performance if the noise levels increase, or you begin to hear different sounds altogether. Any new whining, ticking or whistling could be an indication that the hydraulic pump needs review.

The usual cause of increased noise is a process called cavitation, whereby condensed gases in the system liquid carry low pressure bubbles which implode when external pressure rises. As they implode, they return to liquid state, creating the noise.

Ensure that pumps are operating in the middle of their performance curve to rectify this issue.

Hydraulic pump
Hydraulic pump

Erratic operation of actuators

While there are dozens of reasons that your valve actuators may begin to perform erratically, there are only a small number of components that can cause such problems; the pump is one of them, no doubt.

Cylinders and motors performing erratically can often be linked back to the pump itself. Perhaps there is a decrease in speed and an inability to develop full output? If you notice this, be sure to consider how the hydraulic pump is performing.


Hydraulic pump leaks are caused when fluid bypasses the pump shaft and begins to leak out. While there may be no exterior signs of the pump malfunctioning, decreased performance could be the result of leaks occurring inside the machine itself. Sudden drops in pressure may be an indication of a fault that needs fixing, or risk it leading to a system-wide failure.

By performing regular checks you can reduce the likelihood of the above happening, getting to the roots of the issues before they cause a decrease in performance.

While hydraulic fluid is designed to be lubricated and withstand high temperatures, it can degrade over time, or if it is not suited to its applied environment. Metal wear particles may become suspended in the hydraulic fluid and you can minimise this abrasiveness by keeping your filters clean and regularly changing the fluid. Again, be sure to check your equipment manual for guidance on best practice and recommended change times.

Using flow meter testing

Flow meters are instruments used to measure linear, nonlinear, mass or volumetric flow rate of a liquid or a gas. In our case, they can be used to measure the flow rate of the hydraulic energy being generated by the pump. They are an ideal solution for those servicing hydraulic circuits and machinery, allowing service engineers to quickly and accurately test pumps, motors, valves, cylinders and even complete circuits.

Most kits consist of a direct acting flow indicator, a thermometer (typically inbuilt), a loading valve and a pressure gauge. They are often self-contained units that do not rely on an external power source to run.

General hydraulic pump tests

There are a whole host of general tests that one can utilise to assess the operation of a hydraulic pump.

Check the oil level

This should be obvious to us all, but start with the oil level. It should be three inches above the pump suction, otherwise, air may get into the pump via a vortex in the reservoir.

Check the motor

Some will look at every variable in the circuit before considering the motor. Has it been turned off overnight? Is it working properly? This could be the obvious source of any problems.

At Primary Fluid Power we stock a wide range of piston pumpsvane pumps and gear pumps from Eaton Vickers, Roquet, Rickmeier and Marzocchi. If you can’t find your exact pump on our website, be assured that we have in-house facilities to assemble complete components to meet any urgent needs. We can therefore build and modify hydraulic pumps to your exact specifications.

Overall customer satisfaction is our highest priority at Primary Fluid Power so you can be confident that all our hydraulic pumps are manufactured to the highest standards of quality you expect.

Struggling to find what you are looking for? No problem, contact our sales office directly and we will be more than happy to help