You should check your fluid level at least once every 12 months more often if you use the jack frequently like in a workshop situation.
Floor jack fluid fill.
Works for most heavy and semi heavy quality made floor jacks those throwaway jacks from china over the last 15 or 20 years will blow seals out it s just.
The hydraulic fluid is compressed inside the floor jack and this forces the pistons to rise and this pushes the saddle to lift your vehicle.
Firstly if the hydraulic floor jack is not lifting properly then the oil level is required to be checked.
Once you buy a new floor jack you may use it for 2 to 3 years without having to refill the hydraulic oil.
As a matter of fact without the hydraulic fluid the hydraulic floor jacks cannot work.
Once the jack is lowered locate the oil filler port which is on the bottom of the jack s reservoir near the flat base.
Oil contamination could also be one of the reasons.
Then remove the plug or screw from the oil.