How to Fix a 3-Ton Hydraulic Floor Jack

by Will Chandler
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Thomas Hooke/Demand Media

Floor jacks lift objects by hydraulic pressure which is generated by forcing fluids from one area into another area. Generally these areas are cylinders, and one cylinder is larger than the other. The large cylinder is the reservoir and the small cylinder is a pressure chamber that will generate lifting power. Repairing a floor jack is simple and only requires minimal tools.

Step 1

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Wipe clean the cylinder of the floor jack. Any debris that can fall into the chamber can cause a blockage and result in the floor jack failing to operate properly. Use the shop cloth to wipe down the cylinder.

Step 2

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Remove the plug by inserting a flat head screwdriver underneath the plug and prying it out of place. Most of the plugs will be made of rubber, and will be located on the top of the cylinder. They are usually circular and about 1/2 inch in diameter.

Step 3

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Fill the chamber with hydraulic fluid. Depending on the make and model of the jack, some can hold up to a pint of fluid. Use the funnel to guide the fluid into the cylinder. A substitute for hydraulic fluid is 5W-30 motor oil. Hydraulic fluid would be best, but oil can be used temporarily.

Step 4

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Replace the plug and clean any excess fluid off the floor jack. Test out the jack by pumping the lift arm several times and releasing the arm. Do not attempt to use the jack without testing it first. Repeat the process, if necessary. A new cylinder can be purchased online if the floor jack will not operate properly (See Resources for link to website). Several retailers such as Sears, Harbor Freight, and Craftsman offer replacement parts.

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