It sounds like the sync valves in the jack to me too, i would check to see if each stage of the piston is in the same position from the cylinder head on both sides and that the first stage is in proportion to the second stage on each jack, i had much the same problem on a side/direct acting furse a little while ago, one of the stages of the jack would hit the back of the cylinder causing the lift to stop an inch high at the lowest floor...
As replacement parts were unavailable a new jack was fitted :-)
Last edited by Pete Da Engineer; 08/30/14 12:05 AM.
