I have an older 843 that I ma working on. Machine runs but needs some more work. I have done quite a bit too it but still need more. Needs new carrier seals but I think I got that covered. My problem is when I go to lower the lift arms some times they come down slow but other times they drop violently! I mean like from 4' to the ground instantly. Linkage is a little stiff but does move. Manual shows an orfice #15 in hydraluic schematic on the line to the cylinders. The control valve was "rebuilt" right before I got machine. I know the guy that rebuilt the valve and trust his ability to do it right but the previous owner removed the valve to took it too t his mechanic. I am thinking he may have lost this orfice when he removed valve. Would that cause this problem? I have not pulled any lines to check for the orfice yet, trying to find what all could cause problem. Thanks for any help James.