Hydraulic shop jacks are used to lift automobiles, shop equipment and other heavy equipment easily and safely. They work by pushing fluid — usually oil — to push pistons that lift the heavy objects up off the ground.
When you buy a hydraulic jack new, it usually will come already filled with oil. But in some cases, the oil must be filled manually. In other cases, the oil may have leaked out of the hydraulic jack, requiring it to be refilled before it can function properly.
Two Types of Hydraulic Jacks
Hydraulic jacks are broken down into two main types: The hydraulic bottle jack and the hydraulic floor jack.
Both operate in the same way, with one important exception: With a hydraulic floor jack, the piston operates horizontal to the floor surface. On a bottle jack, this is reversed. The piston operates vertical to the floor surface.
How to Refill a Floor Jack
To refill a floor jack, you must first lower the jack into its lowest position. This can be done by turning the jack’s release valve counterclockwise until it is lowered all the way to the floor level.
The next step is to locate the hydraulic floor jack’s filler port. This is how you can access the jack’s oil reservoir, which is the vertical cylinder located on the flat base of the jack. You typically can find the filler port near the bottom of the reservoir, closest to the flat base of the jack.
Once you have located the filler port, simply unscrew the access plug or screw and place it somewhere nearby where you won’t lose it. It’s agood idea to place the filler cap on or near the jack and off the ground so that it can’t accidentally get bumped or kicked so that it gets lost. If you lose the plug or screw, you won’t be able to reseal the reservoir and the jack won’t work properly until you replace it.
Once the plug or screw has been removed, simply insert the nozzle of the oil can or bottle into the oil filler port and pour the oil from the can into the reservoir. Keep filling the reservoir until you can see the oil approaching the top of the oil filler port. Try to avoid letting it overflow otherwise you will have a slippery mess to clean up.
Once the reservoir has been filled, replace the plug or screw into the oil filter port and screw it on tightly, creating a seal.
Refilling a Bottle Jack
To refill a bottle jack, you must also first lower the jack to its lowest position by turning the release valve counterclockwise until it is all the way down.
Then locate the filler hole, which can be found about 1/3 of the way down the side of the top of the vertical reservoir.
Remove the plug or screw — again, keeping it somewhere safe where you won’t lose it — then fill the reservoir with an oil can or bottle via the filler hole, stopping once the oil has riven to near the top of the filler hole. Replace the cap and screw it on tightly.