A forklift must be checked properly and given a test run prior to purchasing it. This applies specifically to trucks being obtained online. It is vital to detect possible issues with trucks bought from businesses online.
Starting the engine from cold is a good idea. Note whether there is excessive smoke and the ease with which the engine turns over. This is especially essential with IC engine trucks.
The test run should include a check of the truck's performance in tough situations. An operator who is trained could drive the truck in forward and reverse, up the ramp.
You can perform your own inspection of an IC engine truck. On a clear area of floor, run the truck around for a few minutes while a skilled operator tests the hydraulic functions. Afterward, look at the ground underneath for indications of fluid leakage. Even seemingly minor leaking could indicate serious issues which will be really costly to repair later on.
A qualified individual must inspect the masts and chains. Check with and without a load that the mast works smoothly. Watch for 'binding' or sticking of the mast. A warning indication is play in the mast channels or between the fork carriage and mast. One more is creeping forward or creeping down of the mast when loaded. These could be signs of problems with valve, seals or ram.
If the truck is used, the mast might have been changed at some time. Make sure that the mast and any fitted attachments adhere to the rating plate on a truck. Check that the sideshift is not sticking when loaded.
When checking the forks, look closely at the heel thickness for wear or damage. The truck's manufacturer specifies minimum thickness. A loose fit might mean the hanger points or carriage are worn. Watch for cracks on the arms at mountings and heels.