Pallet jacks, also known as pallet trucks, are manually operated industrial devices to lift palletised material off the floor and transport it. The typical pallet jack has two forks similar to those of a forklift, spaced at a standard distance to engage with pallets. Pulling the operator's handle up and down operates a hydraulic pump and cylinder to lift the fork arms several inches off the ground. The operator also uses the handle to tow the pallet and steer it. Hydraulic seals can leak oil over time, causing the pump to malfunction. Also, hydraulic oil may become contaminated. Regularly checking hydraulic oil in a pallet truck is a priority maintenance procedure.
Check the hydraulic oil in a pallet jack at least once a month or according to pallet jack manufacturer recommendations. Check hydraulic oil immediately if seepage or any other external sign of a defective seal is noted.
Lower the pallet forks completely and place the handle in the upright vertical position.
Locate the hydraulic pump assembly. The pump and reservoir are located at the base of the handle assembly, just behind the hydraulic lifting cylinder and piston.
Remove the fill plug from the side of the pump reservoir with an end wrench.
Check the level of hydraulic oil. It should be at or very close to the fill plug opening. Also, note the colour of the hydraulic oil. If it is milky in appearance, it is contaminated. In such an instance you should drain the reservoir and refill it with fresh oil.
Top off with standard 10W industrial hydraulic oil to bring the level up to the fill plug. Replace the fill plug and washer, and tighten with an end wrench.