hydraulic cylinder on an earthmoving machine excavator that may have dieseling which can damage hydraulic seals and piston so you need to contact A1 hydraulic engineering to reseal, reman, remanufacture, manufacture hydraulic cylinders

5 Steps To Remove Air Form Hydraulic Cylinders

Whenever you are installing a hydraulic cylinder to your machine, you should always assume that some air will be introduced in the hydraulic system. 

You can lose oil during the process of disconnecting and reconnecting hoses, fittings, burst/craning valves, or even when installing hydraulic cylinder that’s completely empty.

All these situations are not a problem when you understand what dieseling is.


What's dieseling?

Simply put it’s the detonation of trapped air in oil when compressed. Just think about how a diesel engine works.

Dieseling can damage pistons and the seals. Shortening the life of the hydraulic cylinder.

It also means it reduces machine uptime.

That’s why it best practice to bleed or remove air after any hydraulic cylinder service, when getting a new cylinder, or when there’s a possibility of air that’s entered into the hydraulic cylinders,

Before You Start

Check the machine’s maintenance manual for the procedure that’s specific or recommended for you. The below procedure is general guideline.

You need to keep the machines’ engine at a low RPM/idle throughout the whole procedure.

And be patient. Don’t rush this important process. Don’t run the engine at full noise and sudden control movements to fill the hydraulic cylinder quicker.

You are only promoting for dieseling to occur.

The 5 Steps

Keep the engine at low idle and then…

Step 1: For 8 cycles, slowly extended and retracted the cylinder through approximately 3/4 of the full cylinder travel. Do this for 8 to 10 cycles. Don’t let the cylinders reach the stroke ends (bottom out), in both directions.

Step 2: Pause before you change direction for a minimum of 5 seconds.

Step 3: Then, slowly cycle the hydraulic cylinders to the full extend and retract travel, while keeping the hydraulic pressure low.

Step 4: Pause before you change direction for a minimum of 5 seconds.

Step 5: Finally, check the hydraulic oil level and top up as needed.

Getting Your Hydraulic Cylinder Serviced

If your machines’ hydraulic cylinders are leaking, loosing efficiency, or if you suspect that dieseling has occurred…

Contact us now on 07 3800 8721 and a friendly team member will help you get the best solution.

Written by The A1HE Team

Date: 14.03.2024