I have a 1957 Ford 850 which has developed a stuttering problem when lifting an implement. I previously removed the lift cover, replaced O-rings, piston o-ring seal, cam follower pin and made adjustments according to the FO 20 manual. I did not disassemble any valves. Reinstalled and all was well. It smoothly lifted as it should. ( I was a happy camper as it was my first time working on the hydraulics and IT WORKED! ) I have been using it for about 4 hours of disc work. It has developed a stutter when it lifts. Excuse the terminology, best I can think of. Oil is good, no water and full. I would appreciate any suggestions in diagnosing/solving the problem. Thanks.