How to Pressure Test a Hydraulic Cylinder

How to Pressure Test a Hydraulic Cylinder

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Every year, 1000s of hydraulic cylinders pass through H&R and continually throughout our processes you'll hear the repeated mantra of “Inspect and Test.” For cylinders, one way we confirm and test the quality of our products and our processes is the hydraulic cylinder pressure test.

Learn more and watch along in the video at the end of this post as we explain our hydraulic pressure testing process.

Why Pressure Test a Cylinder

  • The ability to hold pressure is paramount to the action of a hydraulic cylinder and an inability to hold pressure is a clear sign of failing conditions in seals, other parts, and even the cylinder housing.
  • Even though elements of the cylinder and the cylinder in general will have been inspected during the rebuild process, a final inspection of the cylinder’s ability to hold pressure is a final confirmation of the cylinder’s quality and reliability.
  • While externally leaking seals are often visually evident, internal seals must also be tested to ensure hydraulic fluid does not leak from one cavity to the other inside of the cylinder.
  • Externally leaking seals lead to hydraulic fluid loss, loss of power, and can expose the cylinder to increased degradation.
  • Internally leaking seals lead to a loss of performance and power and excessive energy consumption to account for losses.
  • Securing and replacing a hydraulic cylinder on a heavy construction equipment machine can be a laborious and time-consuming process so ensuring a replacement cylinder has been thoroughly and rigorously tested is an indisputable way of confirming a cylinder will last and perform as expected.

    Learn more about How Hydraulic Cylinders Work.

What is a Hydraulic Cylinder Test Stand

  • A hydraulic cylinder test stand is simply an apparatus capable of mirroring the conditions a hydraulic cylinder will be subjected to once mounted to the machine and reporting the results as the cylinder is tested. 
  • A hydraulic tank, an electrically-powered hydraulic pump, hydraulic lines and fittings, and gauges to measure pressure allow the cylinder to be exposed to high degrees of pressure and for the results to be measured and recorded. 
Hydraulic Cylinder Testing Stand
This hydraulic cylinder testing stand is smaller and more mobile than others to allow it to come to they cylinder for testing.

How to Pressure Test a Hydraulic Cylinder

  • The cylinder is mounted and secured using a combination of straps, supports, and surfaces or physically mounted to a testing and inspection stand. Larger and heavier cylinders must be mounted with additional safeguards to prevent unintended movement. As the rod extends the cylinder’s center of gravity will move and in working with cylinders for large construction equipment that movement can be catastrophic to an improperly secured cylinder.
  • The cylinder is attached to the hydraulic lines of one of the H&R hydraulic pressure test stands.
  • The rod is fully extended and held at full pressure for a short period of time.
  • Seals are inspected to ensure hydraulic oil doesn’t leak out.
  • The holding pressure is measured to ensure it remains steady at full pressure.
  • The rod is fully retracted and the technician checks the gauges to ensure they are steady at this stage, as well.
  • The cylinder must be able to reach a holding pressure of at least 3000 PSI to ensure there are no leaks.
    • Every cylinder has a maximum pressure (burst pressure) and the technician must be aware to never exceed that pressure.
  • In the video, you’ll see this Volvo L150G lift cylinder passed inspection.

    Learn how to How to Inspect a Hydraulic Cylinder

Ensuring our products are rigorously tested is one way in which we know we are taking every step to guarantee we produce the best product possible, but it's also a way in which we highlight our commitment to our customers -- we believe a rebuilt part from H&R should get you back up and running quickly and it should keep you up and running for the long haul. 

If you’re searching for a replacement hydraulic cylinder, as always, our dedicated Parts Specialists are your resource for connecting you to a cylinder solution.