Any forklift operator will tell you that one of the scariest things that can happen is for the hydraulic system on the forks to fail. Such a failure can cause harm to individuals in the work area. The load may drop on them or shrapnel from the load may hit them. Being able to properly troubleshoot your forks hydraulics prior to your shift will help ensure your safety and that of you coworkers.
Wipe down the rods that are part of the cylinder. Raise the forks. See if there is a coat of oil on the piston rod from the cylinder. If there is more than a thin coat or streaking there may a problem with the seals inside the rod. This will require a trained professional to make the repair.
Check the level of hydraulic fluid. Make sure that it is full. There are two potential methods for measuring the fluid level. One is visual - viewing a line on the semi-clear plastic. The other is the traditional dipstick that is pulled out and examined. It will have a fill line on it. If it is not full it will allow air to enter into the cylinder. This can cause damage to the seals and burping of the forks. The burping will make the forks move in a jerking motion.
Examine the motion of the forks. If they are jerky and but yet the hydraulic levels are normal there may be a problem with the hydraulic fluid pump. The pump may be clogged or may have gone out completely. This will have to be examined by a professionally trained technician.
Examine all the lines coming to and going out from the cylinders. Wipe them off with a cloth. Move the forks a few times and see if the hoses are leaking at the connections or if they are leaking somewhere in the line itself. These will have to be repaired or replaced by a trained technician.