Hydraulic jacks are used to lift heavy objects, such as cars. They are standard tools in automotive shops. Hydraulic jacks require fluid to push the pistons that lift heavy objects off of the ground. You can purchase a hydraulic jack, and the oil required to make it function, at an auto parts store. Use these tips to add oil to a hydraulic jack.

Things You'll Need

Hydraulic jack
Screwdriver
Oil
Owner's manual for the hydraulic jack

Method 1 of 3: Select the Type of Hydraulic Jack

1
Choose either a hydraulic floor jack or a hydraulic bottle jack. A floor jack has a piston that operates in a horizontal motion. A bottle jack features a piston that moves vertically.

Method 2 of 3: Add Oil to a Hydraulic Floor Jack

1
Prepare the jack. Ensure that the jack is completely lowered. Turn the jack's release valve counterclockwise to lower the jack if necessary.
2
Locate the oil filler port. The hydraulic jack's oil filler port is located on the jack's reservoir. The reservoir is the vertical cylinder mounted on the flat base of the jack. The oil filler port is located towards the bottom of the reservoir, near the flat base of the jack.
3
Add the oil.
- Remove the plug or screw from the oil filler port.
- Insert the nozzle of the oilcan into the oil filler port.
- Pour oil into the oil filler port.
- Stop pouring the oil as soon as it begins to leak out of the oil filler port.
4
Close the oil filler port. Replace the plug or screw in the oil filler port.

Method 3 of 3: Add Oil to a Hydraulic Bottle Jack

1
Prepare the jack. Ensure that the jack is completely lowered. Turn the jack's release valve counterclockwise to lower the jack if necessary.
2
Locate the filler hole. Find the hydraulic jack's reservoir. The reservoir is the largest external cylinder on the jack. There should be a plug or screw approximately 1/3 of the way down from the top of the reservoir.
3
Add the oil.
- Remove the plug or screw from the filler hole.
- Place the nozzle of the oilcan into the filler hole.
- Pour oil into the filler hole.
- Stop pouring the oil once it has risen to a level 1/8 inch (.3 cm) beneath the filler hole.
4
Close the filler hole. Replace the plug or screw in the filler hole.
Tips
- Consult the owner's manual for your particular hydraulic jack. Each brand of hydraulic jack is made differently, and may require unique means of moving through the general process of filling the jack with oil.
  Warnings
  - Be sure to remove all air inside the jack after filling with fluid. Most jacks can be bled by raising it in its highest position then releasing. This should be done 2-3 times before first use.
  - Do not open the overload valves or check valves. Tampering with overload or check valves may damage bearings or springs in the hydraulic jack.
  - Do not fill the jack with any fluid that contains alcohol. Brake fluid should not be used in a hydraulic jack.