Basically, fluid – particularly oil – is the main lifeline of every reliable hydraulic air bottle jacks, be it bottle jacks or service jacks. It is what pushes the pistons upwards to do the heavy lifting. Without oil, it won’t be able to perform its usual tasks of lifting heavy loads, that’s why always make it a point to check the level of the oil in your hydraulic jack to maintain its lasting usability.

Being that most of us likes to DIY, here are some quick steps on how to change the oil of your hydraulic jacks:
To begin with, you might need to get by a little help from your trusty tools to get this job done (especially for the newbies out there). What you will need is a screw driver, pair of pliers, and a small funnel.

Also, it is highly advised not to use brake fluid or motor oil or even ATF, as those kinds of oil may and can damage or corrode the seals as well as the insides of your jack’s oil reservoir due to higher chemical contents. For best results, use ISO 150 or AW-32 hydraulic oil because of its low viscosity characteristics. Once you have completed these things, time to drain and fill up the jack:

First thing you need to do is lower or collapse the jack’s ram lift by loosening the release valve, which is a tiny screw-like bolt located near the jack’s main pump. As for bottle jacks, the ram should be lowered as well.
Locate the jack’s oil plug and remove it (not to be confused with the other screw with a rubber cover that says DO NOT ADJUST). For floor jacks, most plugs are placed right under the main pump, and might need to take it out as well. In bottle jacks, it should be located on the side of the cylinder. If your jack needs to be drained, you may do so by repeatedly pumping it while it is tilted.
Using the funnel, slowly fill the jack with hydraulic oil. Make sure the reservoir is full. You’ll know this once it starts to leak out.
After which, tightly close the jack’s oil plug back. Next thing to do is to tighten the release valve, then give it a few pumps to ensure the oil goes to the jack’s reservoir/hydraulics chamber.

Although it is not highly-suggested to change your hydraulic oil frequently, it is better to check first its condition, as well as its performance before deciding to replace it. However, the usual serving time of a typical hydraulic oil can reach up to a good 6 months to 1 year.

Mingrui is one of the vehicle positioning jacks manufacturer and welcome to your come and purchase!