How to Fill a Bottle Jack

How to Fill a Bottle Jack

This blog is reader-supported. When you buy through links on our site, we may earn an affiliate commission at no cost to you.

If you’re a newcomer in the world of car jacks, then a jack is a tool that’s used to lift heavy objects such as your truck, Jeep, or SUV vehicle. For that to happen, it relies on an internal mechanism that relies on oil or grease for proper lubrication. Jacks come in different types and variations, with the bottle jack being one of the most popular. And since it’s highly likely to have one of these in your car’s toolbox, learning how to fill a bottle jack is very essential for any enthusiast DIYer.

Now, the reason why the bottle jack is quite different from other floor jacks is its unique upright bottlelike appearance and small manageable size. In most cases, this jack comes in different weight ratings that range from 1.5-tons to 200-tons with the 1.5- to 5-ton being the most dominant.

Just like any other machine, replacing the old oil with new young oil is very important for better performance. Since the bottle jack is among these machines, this guide has offered a simple step-by-step walkthrough on how to fill this type of floor jack.


But First, What’s the Working Mechanism of a Bottle Jack?


Before we discuss how to fill or refill a bottle jack, it’s important to understand the working mechanism of this particular jack. This way, you’ll realize the importance of filling it with oil. Now, the bottle and the floor jack are the two main types of jacks that use the hydraulic principle to lift heavyweights.

The floor jack on its part has a horizontal piston that gives it a low profile enough to lift vehicles with low ground clearance. On the other hand, the bottle jack has a vertical piston that gives it a high default height. For this reason, this type of jack is used to lift vehicles with a higher ground clearance such as trucks, SUVs, and lifted Jeeps.

So, how does a bottle jack work? Now, the bottle jack contains a small reservoir on the inside that contains the oil. When you pull the handle, this oil automatically transfers from the reservoir to a piston.

When you push the handle up and down, oil from the smaller piston is forced inside the larger piston to create pressure inside the cylinder. This pressure is what the bottle jack uses as the power to lift your vehicle off the ground.

Once you’re through inspecting your vehicle, the next step is to lower the vehicle to the ground. To do this, you need to use the release valve to get the oil back into the reservoir.


Why Use Oil For Hydraulic Fluid?


Now, the bottle jack uses the hydraulic system to lift loads. Since all hydraulic systems rely on oil to function, this jack will also need oil to transfer mechanical energy into lifting power. But, despite being an efficient tool, a bottle jack suffers one major flaw, which is frequent oil leakage.

Although the reservoir and the locking points are tightened to prevent any leakage, there are times when leakage might be inevitable, especially when you’re descending the jack. Since frequent use of the jack will deplete the oil eventually, topping it up is important to maintain efficiency.

When putting oil in your bottle jack, you should put the right amount to avoid overfilling the jack. Since different bottle jacks have different sizes and different load capacities, you need to follow the manual to know the right amount of oil to use on your jack.

Lastly, avoid using brake fluid, transmission oil, motor oil, or any alcoholic oils in your bottle jack. Also, avoid mixing different oils then filling them in your jack. By using such oils, you’ll end up damaging your hydraulic system, which is not good for the health of your jack.

So, to avoid this, always use a graded hydraulic oil to enhance adequate lubrication and lower the chances of corrosion.


So, How Do You Fill A Bottle Jack?

Things You’ll Need

  • Screwdriver
  • Hydraulic oil
  • Plastic squeeze bottle
  • Rag
  • Old newspapers

The Process

Step One: Start by placing your bottle jack on the flat-level ground. This will prevent the jack from tilting over when you’re filling it with oil. Also, a flat surface will help to keep the oil level allowing you to fill the chamber accurately. Also, make sure that you place rags or old newspapers on the floor to prevent ruining the surface with oil spills.

Step Two: Look for the release valve and open it to gain access to the filler hole. Depending on your jack’s model, the release valve may have a unique release mechanism. Some jacks require you to press a release valve on the side of the cylinder while others demand that you rotate the handle counter-clockwise.

Step Three: Next, locate the filler plug on your bottle jack. Some models will force you to open a cover plate that protects the jack’s internal mechanism while others will have a rubber cover that seals the filler plug. So, in either case, you’ll have to use a screwdriver, whether flat or star headed, to remove the screws.

But, before doing this, make sure that you clean the area surrounding the filler plug carefully to remove any dirt, debris, or oil build-up in the area. By doing this, you’ll keep dirt and debris off the oil reservoir once you open the filler plug.

Step Four: Once you’re done cleaning, use a star or a flat-headed screwdriver to open the filler plug screw. Make sure that you open the screw slowly to prevent excess oil from gushing out of the reservoir.

Step Five: With the filler plug screw out of the way, it’s now time to fill the reservoir with new and young hydraulic oil. In case you have enough oil at your disposal, then you can consider bleeding the old oil off your jack and fill it with entirely new oil.

To bleed the old oil off the reservoir, simply tilt the jack to hold it horizontally with the filler hole facing the ground. Place a container on the ground and allow the old oil to drain off. Once you’ve drained all the oil from the reservoir, place the bottle jack in its initial vertical position and get ready to fill your new oil.

So, to fill the new oil, you’ll need to use a plastic squeeze bottle or a funnel. In the case of a squeeze bottle, make sure the tip is long and pointed to fit inside the filler hole. So, with everything ready, squeeze the tip of the squeeze bottle inside the filler hole and start squeezing the bottle to fill the reservoir with oil.

Step Six: Once you’ve filled the reservoir with oil, replace the filler plug to lock it securely. You can try prying it open with your fingers to see whether it will open easily. Lastly, use a clean cloth or a rag to wipe off any excess oil on the side of the bottle jack.


Bleeding Air From a Bottle Jack


Step One: The reason why it’s important to bleed off excess air from your bottle jack is to avoid excess air build-up that can affect the efficiency of the jack when lifting weight. So, start by opening the release valve by turning it counter-clockwise.

Step Two: With the release valve open, grab the handle and pump the jack several times, most preferably 10 to 15 times. This way, any excess air inside the jack will be drawn off the jack system. Also, the jack shouldn’t rise while the release valve is open.

Step Three: When you’re done, twist the handle of the release valve clockwise to lock it. Test the jack by pumping it to ensure that it rises in smooth even motion. In case it doesn’t rise, then it means the release valve is not locked correctly.




It’s that simple! As you can see, filling a bottle jack is not as complex as it sounds. The process is just a matter of using the right tools and following your jack’s manual to understand its mechanism. When filling the oil, always use the right hydraulic oil to avoid damaging the jack’s mechanism.

Also, ensure that you apply the right amount of oil to avoid overfilling the reservoir. Always remember to bleed out any excess air in the system to guarantee efficiency. Lastly, wipe out any excess oil on the jack, and don’t forget to test it after you’ve completed the entire process.

Leave a Comment

Your email address will not be published. Required fields are marked *

Scroll to Top