Sunex floor jack


It’s frustrating when you need to lift something with your trusty floor jack, but discover that your previously reliable jack will only lift part-way, or not at all. Othertimes, the jack might be stuck in a lifted position and won’t lower.


For those encountering a stuck jack for the first time, having your jack stuck in the up or down position can elicit the kind of choice language that generally upsets our mothers, and ruins your plans to work on your car or truck.

The good news is that it’s usually* a fast and easy fix, and our friends at Sunex have made a short and accessible video for floor-jack maintenance which should help you solve your trapped-air problem as well as show you how to lubriate your floor jack properly to keep it in tip-top shape for the next time you need it.

(* – sometimes the universe conspires against you, and neither we nor the capable tool experts at Sunex can help you if you’re on the Cosmic Naughty List.)

How to Bleed Air Trapped in a Hydraulic Floor Jack

The most-common reason a floorjack would be stuck in the up or down position would be because of air trapped within the hydraulic pump, preventing the jack from having full range or lifting/lowering capabilities.

You need to bleed or purge the air from the jack, which isn’t difficult once you know how.

1. Rotate, or spin, handle to the right until it stops.

2. Back it up two turns to the left.

3. Pump the jack 10-15 times to release trapped air.

4. Turn the handle all the way to the right to close the relief valve.

Afterward, jack functionality should be back to normal. Now, get to work!

How to Properly Lubricate a Hydraulic Floor Jack

1. Acquire grease.

2. Apply grease to key floor jack components, which are the following:

  • Lift arm pivot pin
  • Axles on front wheels
  • Bearings under caster wheel bracket
  • Back rollers which come into contact with pump plungers
  • Universal joint near release valve
  • Handle base on inside surface of the female handle receiver (must remove handle to access)
Author: Matt Griswold

After a 10-year newspaper journalism career, Matt Griswold spent another decade writing about the automotive aftermarket and motorsports. He was part of the original OnAllCylinders editorial team when it launched in 2012.