How to Add Oil to Floor Jacks

by Steven Douglas
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Floor jacks are useful tools that should last for many years with very little maintenance. Although floor jacks do not "consume" oil, it may leak out from one of several places over time. For safety's sake, it is always a good idea to check the various components of the jack during the oil filling procedure to determine whether the jack is safe to use. The reason for having to add oil should always be investigated as part of this maintenance procedure.

Step 1

Place the floor jack on a hard, level surface. Put the jack in the down position by opening the release valve--the valve that when opened allows oil to flow back into the main oil reservoir located at the bottom of the jack, thus lowering the ram piston. Look for any oil seepage around this valve. Wipe off the area around the release valve with a clean rag.

Step 2

Locate the oil fill plug. On older jacks, this plug may be hidden behind a removable cover near the bottom of the jack. On newer jacks, this plug is usually located near the top of the oil reservoir (cylinder containing oil when the unit is in the down position). Once you've located the plug, look for any oil seepage around the plug, and wipe the area clean with a rag to prevent contamination during the refill step.

Step 3

Remove the oil fill plug by unscrewing it with a large slotted screwdriver or an Allen wrench, depending on the manufacturer. Once the plug is removed, use a flashlight to look into the oil filler hole. The oil level should be 1/8 inch below the neck (opening) of the oil filler hole.

Step 4

Add oil by inserting a small funnel into the oil filler hole, then slowly add a small quantity of jack oil. Remove the funnel. Wait 30 seconds for the oil to dissipate, then check the level with the flashlight method again.

Step 5

Replace the oil fill plug, and wipe up any spilled hydraulic jack oil. Raise the jack to the full up position by pumping the pump handle. Look for any oil seepage around this handle. Once the jack is in the full up position, inspect the ram piston for oil seepage. The ram piston is the component that actually raises the item being lifted during the jacking process. Wipe away any oil from the ram piston.

Release the jack to the full down position. Inspect the area under the jack for oil seepage.


  • If you found excessive oil around any components of the jack during the oil filling process, the jack may require oil seal replacement. Oil may be added frequently, but excessive oil loss will reduce the holding power of the jack thus rendering it unsafe in some conditions.


  • Do not use brake fluid in a hydraulic jack. The alcohol content in the brake fluid will destroy the seals in the hydraulic jack very quickly.

Items you will need

  • Clean rags
  • Hydraulic jack oil (or as suggested by manufacturer)
  • Small funnel
  • Flashlight
  • Slotted screwdriver or Allen wrench

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