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How to bleed a bottle jack?

Views: 22     Author: Site Editor     Publish Time: 2020-09-15      Origin: Site

We often use bottle jacks to help us work. Although we have learned how to use the bottle jack, there is no problem in normal use. However, when we use it for a certain period of time, we will find that the bottle jack is not as easy to use as before or cannot be operated at all. Then we need to know that air may enter the bottle jack, so we need to know how to bleed the bottle jack.

This article contains the following:

When should i bleed a bottle jack?

Steps to bleed the bottle jack

Precautions for bottle jacks bleed


1.When should i bleed a bottle jack?

bottle jacks sometimes need to be bleeded, especially if you use tools on a regular basis or recently transported them. When there is air in the bottle jack system, it will not work properly and will not be able to lift the load. When the bottle jack cannot be heavily loaded according to the manufacturer's instructions, you need to bleed the bottle jack, or the bottle jack slowly loses height when lifting heavy objects, but in most cases, if there is air in the system, the bottle jack will not lift at all heavy. So we need to bleed the bottle jack regularly


2.Steps to bleed the bottle jack

(1) If the bottle jack is attached to an engine hoist, I suggest removing it from the hoist before bleeding it;

(2) Take a pump handle and open the bleed valve by turning it counterclockwise. The bleed valve is usually located on the bottom of the bottle jack, next to the pump handle socket. Wait till the ram is lowered to the lowest position;

(3) Remove the oil fill plug which should be located in the middle on the side of the bottle jack. You may need to use a flathead screwdriver to remove the plug;

(4) Insert the bottle jack’s pumping handle into the handle socket and pump the handle quickly for about 10-20 strokes (how much times you should pump the handle will usually be indicated in the owners manual of the bottle jack, but generally 10-20 is going to be enough). This pumps the oil throughout the system from the oil reservoir to the high-pressure system and back to the reservoir through the bleed valve and takes the air from anywhere in the system with it, so any trapped air from the system ends in the top of the reservoir and goes out of the reservoir through the oil fill plug hole;

(5) Check the oil level in the bottle jack, before placing the oil plug back into the cylinder.

(6) Fill a hydraulic oil into the bottle jack if necessary;

(7) Place the rubber oil plug back into the cylinder;

(8) Close the release valve;

(9) Pump the jack to the maximum height and check if everything works properly.

Reinstall the jack back to the hoist. Test the jack with a lower capacity load before using it to lift a heavy load. If bottle jacks still does not work properly, repeat the steps 1-7.


3. Precautions for bottle jacks deflation

(1) Except for the hydraulic jack oil in the bottle jack, do not use other liquids. Incorrect oil can cause the bottle jack to collapse.

(2) Before performing maintenance on the bottle jack, be sure to read the user manual first. Different models have different mechanisms. Although different types of bottle jacks have similar deflation methods, if there is an instruction manual, please follow the instructions in the manual.


When the bottle jack enters the air, the above-mentioned exhaust method can be adopted. Please pay attention to the precautions of bottle jacks bleed and operate it correctly.


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