Air scissor lift the pressure relief valve to adjust the maximum rating

Hand pallet trucks fuel tank leak will cause the hydraulic cylinder does not rise up . For the following reasons :
the pressure is low , less than load. Check the pressure relief valve .
tanks into the air , will cause instability in the cylinder , the air should be excluded .cylinder relief valve into the dirt , then place in a normally open state of the valve , automatic oil back into the tank , no oil flowing into the fuel tank .the piston side in electric stacker contact with the cylinder head too tight will cause oil pressure get in, can not produce Air scissor lift  enough thrust to make cylinder operation.hand pallet trucks load is too large , the pressure relief valve to adjust the maximum rating, but not force continuous action of the cylinder .leak causes: hydraulic forklift cylinder and piston wear and the gap is too large, if the electric pallet trucks piston seals installed , it is because of wear or aging lost ring seal . Solution: Replace the Air scissor lift piston or replace seals.
if the electric truck tanks often use only a part of the local wear serious gap increases, the cylinder leakage. The workaround is heavy with the Pistons. The reason for this phenomenon is the rod seal too tight , the rod is longer, in part caused by sliding too much pressure , or sliding parts cylinder contamination .