Step 7 of 8 · Test

How to pressure test a hydraulic hose assembly

Proof test the finished assembly with liquid, inside a guarded enclosure, at the pressure and hold time the specification calls for.

  1. 1 Select
  2. 2 Cut
  3. 3 Skive
  4. 4 Insert
  5. 5 Crimp
  6. 6 Clean
  7. 7 Test
  8. 8 Inspect

What this step does

A proof pressure test checks that a finished assembly holds pressure without leaking or moving at the fittings. It is a non-destructive test: the assembly is pressurised above its working pressure and well below its burst pressure, held, and inspected.

For most hydraulic hose the proof pressure is commonly twice the maximum working pressure, held for 30 to 60 seconds, following the method in ISO 1402. Always use the proof pressure the hose manufacturer or the customer specifies for the assembly.

How to do it

  1. Confirm the working pressure of the assembly — the lowest-rated component — and the proof pressure required.
  2. Connect the assembly to the test bench with adapters rated above the test pressure.
  3. Fill with the test liquid, normally water or hydraulic oil, and bleed all air from the hose.
  4. Close the guard or enclosure. Nobody stands in line with the hose or fittings during the test.
  5. Raise the pressure steadily to the proof pressure and hold for the specified time.
  6. Watch the gauge for pressure loss and inspect the fittings and hose for leaks, bulges or movement.
  7. Release the pressure fully before opening the enclosure, then drain and dry the assembly.
  8. Record the test pressure, hold time, date and result against the assembly.

Checks before moving on

  • No leak at either fitting and no weeping through the cover.
  • No movement of the hose out of the shell — the depth mark is unchanged.
  • No blister, bulge or twist in the hose.
  • Pressure held for the full time without topping up.

Common mistakes

  • Testing with air or gas. Compressed gas stores far more energy than liquid, and a failure is explosive. Proof testing is done with liquid.
  • Leaving air trapped in the hose, which makes a failure more violent and hides small leaks.
  • Testing above the proof pressure "to be safe", which can damage a good assembly.
  • Skipping cleaning or drying after a water test.

Equipment and consumables

  • Hydrostatic test bench with a guarded enclosure
  • Calibrated pressure gauge covering the test range
  • Test adapters and plugs for each thread type
  • Test record sheet or labels

Settings such as crimp diameter, skive length, insertion depth and test pressure are specific to the hose and fitting manufacturer. Use their current specification.

Frequently asked questions

What pressure is a hydraulic hose tested at?

A proof test is commonly carried out at twice the maximum working pressure of the assembly. Use the value given by the hose manufacturer or the customer specification.

How long is a hose proof test held?

The ISO 1402 method holds the proof pressure for 30 to 60 seconds while the assembly is inspected for leaks and movement.

Should every hose assembly be pressure tested?

It depends on the application and the customer requirement. Many workshops test every assembly for critical or high-pressure service and test samples from each batch for routine work. A crimp diameter check is done on every assembly either way.

What is the difference between proof pressure and burst pressure?

Proof pressure is a non-destructive test level, commonly twice the working pressure. Burst pressure is the pressure at which the hose is designed to fail, commonly four times the working pressure, and is only reached in destructive type tests.

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