It often happens that after purchasing a long-awaited tool and wanting to try it out immediately, you encounter a surprise – the device does not work smoothly. We understand that this causes disappointment and the first thought is about a faulty or damaged item received. If your new hydraulic jack with wheels (trolley jack) does not lift the load to its maximum height, the handle springs when pumping, or the raised weight slowly lowers, do not rush to think about returning it. Most often, this means a very simple thing – air has entered the hydraulic system.
In this irankiuturgus.com post, we will thoroughly discuss how jacks work, why air appears in the system, and how to quickly and independently bleed a hydraulic jack so that your work proceeds without interruptions.
How does a hydraulic system work?
To understand the problem, it is useful to know how the device works. Hydraulic jacks operate based on Pascal's law and a simple rule of physics: liquids are practically incompressible.
Inside the jack are two main cylinders connected by channels, and a reservoir filled with special hydraulic oil. When you move the jack's handle down, the small piston pushes the oil. Since the fluid is incompressible, it is directed through valves into the large cylinder and lifts the main piston upwards with immense force. When the pressure release valve is opened, the oil returns to the reservoir, and the jack lowers.
Why does air enter the system?
The main rule is that liquid is incompressible, but air is very easily compressible. If air bubbles appear between the hydraulic oil, when pumping the handle, the force is expended not on pushing the liquid, but on compressing the air. This is why the handle becomes "soft" and the lifting force disappears.
It is important to emphasize: air entering the system is not a manufacturing defect. This is a natural and common phenomenon, especially during transportation. When shipping goods, jacks can be turned over or tilted onto their side. During such journeys, the air in the reservoir naturally mixes with the oil and enters the working cylinder. This is a common situation for both household and professional tools.
Hydraulic Jack Bleeding Procedure (Step-by-Step)
Removing air from a hydraulic system is a simple process. Follow these steps:
- Open the release valve: Turn the jack's handle (or release screw) counter-clockwise approximately 1–2 full turns.
- Actively pump: With the valve open, pump the handle about 10–15 times with quick and full strokes. The jack should not rise at this point – this action expels air from the cylinder back into the reservoir.
- Close the release valve: Turn the handle fully clockwise until you feel resistance.
- Release air from the reservoir: Raise the jack to its maximum height without a load. Find the rubber oil filler plug on the main cylinder. Carefully lift it slightly (you may hear the sound of air escaping) and then firmly press it back down.
- Check operation: Lower the jack and raise it again. If it still feels springy, repeat the procedure.
A properly maintained and bled hydraulic jack will ensure safe and smooth operation. If you are looking for reliable equipment for your workshop, we invite you to check out the irankiuturgus.com assortment.
