Once again without the problem solved. I have several forklifts with limited capability because they cannot lower the mast with more than 1200 lbs of weight. Some will not come down with no weight on them. They will come down if the lever is held down for over a minute, in our manufacturing environment that is unacceptable.

I have tried the following.

Safety Down Valve replacement made no change whatsoever.

Valve body dissassembly and inspection, which improved the weight at which this problem occurs slightly.

Total mast cleaning inside the channels, adjusting the chains and lubricating the neccesary components. Which this improved the capacity before problem occurance marginally.

Our fleet has the onboard computers and speed controls. They are all mini-lever controls and have the full suspension seats, all wiring is good, everything checks out to be operating correctly.

The Hydraulic load pressure sensor reports this problem occuring at or around 1.87 volts or higher. I have also performed the minilever relearn function as well as changing hydraulic fluid and filters.