Learn how to refill the hydraulic oil in your floor jack

There are different types of floor jacks on the market, with the main categories being:

  1. Bottle Jack
  2. Scissor Jack
  3. Hydraulic Jack

Most floor jack user find the hydraulic floor jack to be more convenient and easier to use and this is why it tends to be a popular choice for many.

Hydraulic jack are commonly used at auto shops or even at home by most car owners. When you need to accomplish some task and routine repairs, the hydraulic jack comes in handy. This will be used to raise the vehicle off the ground and this gives you access to the components that are underneath the vehicle.

When you have a good floor jack, it should work for a very long time, without any problems. However, this will depend on the level of maintenance and care that you accord your floor jack. Replacing the hydraulic oil is one of the common procedures of ensuring that your floor jack is working as required.

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How the Hydraulic Floor Jack Works?

Before getting into the details of how to refill the hydraulic oil, it is important to understand how the fuel jack works. This will help you understand the critical role played by the hydraulic fluid in the whole process.

Ideally, if you have seen a hydraulic jack, you must have notices that it has a lift arm, which runs horizontally. The arm is lifted by the action of pumping the jack handle, and that is the whole concept, on the surface. However, there are a number of things that happen so as to cause the lift arm to raise and be able to lift the load off the ground.

There are a number of chambers inside the floor jack, with the reservoir being the one that hold the hydraulic oil. When you start pumping the floor jack, using the pump handle, the fluid is drawn from the reservoir. As you pump upwards, a suction force is created and then when the jack arm is pushed down, this forced the hydraulic fluid to move into the check valve.

The check valve will them block the opening of the reservoir, so as to prevent the fluid from going back into the tank. This fluid is forced into the hydraulic cylinder, which is the main chamber of the hydraulic floor jack. There is a ram piston in the cylinder, which will be pushed upwards, when the pressurized hydraulic fluid gets into the main chamber. This is what will cause the saddle to raise and lift your load to your desired height.

Once you are done using the floor jack, you will lower it by turning the release valve, which alleviates the pressure and allows the hydraulic oil to back into the reservoir. In a nutshell, this is how the hydraulic floor jack works.

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Proper Maintenance of Hydraulic Floor Jacks

As we had mentioned earlier, the efficiency and longevity of your hydraulic floor jack depends on the care that you accord it. As long as you are able to maintain the floor jack properly, you should be able to use for a number of years, without any issues.

There are some basic checks that should be conducted every other time that you need to use the floor jack. However, the main maintenance and checks can be done once or twice in a year. The frequency of the maintenance may increase as the floor jack keeps aging.

From the section discussing how the hydraulic floor jack works, you must have realized how important the hydraulic fluid is, to the whole process. As a matter of fact, without the hydraulic fluid, the hydraulic floor jacks cannot work. The hydraulic fluid is compressed inside the floor jack and this forces the pistons to rise, and this pushes the saddle to lift your vehicle.

Once you buy a new floor jack, you may use it for 2 to 3 years, without having to refill the hydraulic oil. Again, this will be determined by the level of maintenance the floor jack receives. The hydraulic fluid is the lifeline of the hydraulic floor jacks and without the oil, you cannot be able to lift any objects off the ground.

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how to fill a hydraulic floor jack with oil Step By Step Guide?

In most cases, manufacturers, suggest that the hydraulic oil should be refilled periodically. Be that as it may, it is advisable to keep checking the condition of the oil. You should also monitor the overall performance of the floor jack, before replacing the oil. With a good floor jack, you will only refill the oil once or twice in a year.

If you have carried out all the necessary checks and conducted due diligence, here are steps to follow when replacing the hydraulic fluid.

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Step – 1: Establish Where the Filler Port is

how to refill the hydraulic oil in your floor jackIf this is the first time to refill the hydraulic oil, then you should start by understanding where the oil goes and which parts are essential. You would need to find the filler port, which will be used for purposes of pouring in the hydraulic oil.

In most models, the filler port will be on top of the floor jack. However, this may vary, depending on the specific model that you are using. It should be marked out as the filler port, but if you are not sure, you should consult the owners’ manual to locate it.

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Step – 2: Remove the Plug

The filler port is covered with a plug, which you will need to uncover this cap so as to be able to refill the oil. A wrench is required to be able to remove the cap, by turning it counterclockwise. Keep the plug safe and check inside the container to see if there is any dirt to debris.

You can blow out the floor jack using compressed air so as to drain any oil that may be contaminated. This will enhance the efficiency of the floor jack, when you refill the oil.

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Step – 3: Refill the Hydraulic Fluid

Refill the Hydraulic FluidPlace a funnel at the opening of the filler port and ensure that it fits perfectly. Only start pouring the oil, when the funnel is in place. The funnel should prevent any unnecessary spills when refilling the oil.

Every floor jack will have the required level of the hydraulic fluid indicated. You should make sure that your oil is poured to this level. This is the only way that the floor jack will be able to work as required. If there is any oil that spills during process, you should wipe it down immediately.

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Step – 4: Put the Plug Back

When you have completed pouring the hydraulic oil into the filler port, you should replace the plug. Before capping the filler port, wipe the plug so as to clean away any dirt or dust. It is not advisable to move the floor jack before the cap is placed back and tightened as it were.

Finally, when you have gone through the whole process, you should test if the floor jack is working, without necessarily having any load on it. You can pump the jack to check if it is pushing up the saddle as expected. Bleeding the cylinder right after refilling the oil is highly recommended.

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When to Refill the Hydraulic Oil?

According to most floor jack manufacturers, the hydraulic fluid should be replaced after about 1 year. If you are not sure when this should happen, there are some signs, which can tell it is time to have the hydraulic oil refilled.

One of the main indicators is when the floor jack seems to strain when you attempt to lift the load. This may imply that the oil level is too low, or even contaminated. Before pouring in new oil, you should drain any oil that is inside the cylinder, as a safety measure, just in case the existing oil has dirt.

When the time comes to refill the hydraulic oil, you should follow the specific steps that have been highlighted above. It is important to note that there are other maintenance procedures that you should carry out, besides refilling the hydraulic oil.

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Storage of the Jack

There are a number of instances where the hydraulic fluid will leak, due to improper storage. Every time you finish using the hydraulic floor jack, you should release the pressure and lower the arm. This will ease up the tension in the floor jack and cause the oil to floor back into the reservoir to avoid contamination.

You hydraulic floor jack should be stored in the upright position at all times. This will prevent any leakage of the hydraulic oil. With proper maintenance and care for your hydraulic floor jack, you will extend its lifespan and it will serve your for a very long period of time. We hope you can now be able to refill the hydraulic oil without a problem.

About Admin

Hey there, my name is Kimani Muhia, I am the one who runs Best Floor Jack Guide. For over 10 years, I have been running a family-owned Auto repair shop. I am happy to assist with any questions or concerns that you may be having about floor jacks. You will learn a whole lot from my experience. Hit me up, in case of anything.

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  1. hugh wynn

    This is the most useless instructions for checking/refilling oil in a floor jack. I can tell the author of this article has no knowledge on maintaining a floor jack.

  2. Jeff

    Nice write up. My only thought is that you could have covered the “bleeding process”, especially if it’s recommended after filling or replacing the oil.


  3. Larry e

    How do I drain the oil In my floor jack?

  4. nisar

    nice blog , i think Hydraulic Jack Oil and its Fluid Properties mean Each and all hydraulic system in use will mainly contain any type of hydraulic fluid. But, you know it not a common hydraulic fluid is used in all applications. more to reed Hydraulic Jack Oil and its Fluid Properties

  5. Jerald Josephs

    So, how does one bleed the Jack after filing?

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