How to Fill a Floor Jack with Hydraulic Oil?

How to fill a floor jack with hydraulic oilIf you own and use a floor jack, you will need to ensure that the hydraulic fluid level is at full for proper and safe operation. Also, you should check your fluid level once every 12 months, especially if you use it frequently (like in a workshop situation). If there is any excess fluid on or around the Jack, don’t forget to check and top up the fluid level if required.

Poper care of hydraulic jack is crucial as it plays a very important role while replacing a wheel. As you might already know that heavy-duty pallet jacks help you in lifting heavy vehicles for changing the wheels, but what most people miss is its timely servicing and oiling which is vital. Plus, Oil is very important as the pistons in the jack require fluid to be pushed, so you can easily learn how to refill the oil in the jacks by just simply going through the procedure. 

How to fill a floor jack with hydraulic oil

The moment you realize that your floor jack is having a problem lifting up your car wheels, you should understand that it is time for you to refill its hydraulic oil. It is recommended to take external help if you feel that your work has not generated the results you were expecting. 

Read the article further to know about refilling your hydraulic floor jack oil

Try to understand the structure of the jack floor

First of all, In order to differentiate between a floor jack and a bottle jack, just have their shape in your mind. Plus, In terms of their way of operation, a floor jack works horizontally, whereas a bottle jack operates vertically, its piston makes vertical movements.

Filling a Floor jack with hydraulic oil

First, prepare your floor jack

Preparing the jack refers to lowering it completely. In order to achieve this, you will require to turn the jack’s relief valve in an anticlockwise direction. Once you lower the jack completely, you will be able to remove air from the jack cylinder. As such, any air that might have remained in the jack cylinder after lowering the jack will be eliminated after you add oil into the jack.

Find the oil filler port/hole

This indicates the opening that’s used to introduce oil into the jack cylinder. Well, In most hydraulic floor jacks, the filler port/hole is found on the floor of the jack’s reservoir. Don’t forget that this reservoir is cylindrical in shape and has a vertical mounting on the jack’s flat base. 

Have a proper look at the bottom part of the reservoir which is close to the jack’s flat base, you would find an oil filler port there. The best part is that all filler ports are well marked/labelled for what they exactly are.

Uncap the filler port and installing a funnel onto the port

After you are done locating the filler port, you will need to uncap it and place the cap somewhere safe in order to avoid inconvenience in finding it later. The next step is to uncap the port, for that you need to turn the cap in an anticlockwise direction, otherwise, it you will end up tightening the cap. 

When you get the cap off the port,  install a funnel into this hole to provide ease in refilling hydraulic oil into the jack. Don’t forget to choose a funnel with the appropriate size according to the port. 

Without the use of a funnel, you would probably experience oil spillage in the process. Plus, the funnel should be held tight once installed into the filler port. This will ensure to reduce any possibility of spilling this oil while in the process of re-filling the jack.

Refill the jack with hydraulic oil

Don’t forget to make sure that you have acquired the right hydraulic oil, now get ready for the refill exercise. Just uncap the oil container and put the oil into the funnel attached to the oil filler port. Before you start pouring the oil into the oil filler through the funnel, Please ensure the oil container’s nozzle rests on the funnel or is slightly into the funnel. 

Now slowly but steadily pour the oil into the funnel. While you pour the oil into the funnel, It is important to keep monitoring its level inside the jack cylinder. Once the oil starts to leak out of the oil filler port, you need to stop right there. Also, You should take caution not to spill the oil on either the floor or jack. Well, even if you spill it on either the jack or the floor/working table, make an effort to clean it.

Place back the oil filler port cap

After you are done filling the jack with hydraulic oil to your satisfaction, now you need to secure the filler hole with its cap. This will ensure the jack stays oil leakage-free. If it has a cap is of screw type, try to avoid over-screwing it. Sometimes, applying unnecessarily huge force when placing back the cap can possibly lead to its damage or screw threads.


After refilling the floor jack with hydraulic oil, test and ascertain that the jack is working as per your expectations. Sometimes, jack users complain that their jack fails to extend fully while carrying a huge load after refilling it. Well, this condition has been attributed to something called air bubbles in the hydraulic system. 

In order to cure this problem, you will require to depress the jack. Open its relief valve and pump it for about 10-15 stokes, before you close it. After doing this, check its operation. This process successfully eliminates any air that may be trapped in the jack’s cylinder. If still the performance (full extension of the jack) of the jack still remains unsatisfactory, you can repeat this procedure.

Janathan Greez
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