If your jack needs oil, even after a couple of years, it probably also needs new seals. Adding oil might let you use it a while longer, but you should probably replace the seals (or if it's a cheap Chinese/Taiwanese jack, just get a new jack). American- or Japanese-made jacks are probably worth resealing. Please always use jack stands so when the seals really blow out you don't end up crushed.
You're probably going to just put jack oil in anyway (or maybe you did replace the seals and now you need to put jack oil in), so here's how to do it:
Remember to always work on hard, level ground, use jack stands, chock the wheels, and set the parking brake.
do you need to fill the hydraulic cylinder all the way up with jack fluid or leave some air in it?
Hydraulic fluid should be poured in the oil tank.
You can add hydraulic fluid to Porsche convertible top motor by popping open your engine hood and then pouring the hydraulic fluid into the appropriate compartment.
under the seat were do you add the hydraulic fluid
In a Ford 4610, you need to add the hydraulic fluid to the rear axle. The Ford 4610 is a 1989 tractor that retailed at close to $19,000.
In the master cylinder
This depends on what type of vehicle that you have. But in most vehicles you would add the brake fluid to the master cylinder. This can be located on the firewall of your vehicle. Do not confuse a clutch master cylinder with the brake.Make sure you add the fluid to the brake cylinder.
The clutch hydraulic fluid reservoir for a Mazda 121 is located next to the brake booster and brake master cylinder. The reservoir is small and round and is close to the driver side fender.
in the back axle
Follow this link (or copy and paste into your browser's address bar): http://www.hyjacks.com/H7.HTM then scroll about halfway down to find the instructions you seek. The task is a bit easier with a very small funnel that fits into the fluid reservoir hole.
Depends on which machine, I drove many and do remember they all had an easily accessible hydraulic tank.
You don't. You add it to the master cylinder and bleed the brakes.
Remove the fill cap and add it at the brake fluid master cylinder reservoir. Located on or near the master cylinder.