I have a customers Genie telehandler that is snapping the yoke off of the rear fork leveling cylinder twice ,have contacted and discussed possible reasons for this with the manufacurer and they have stated that they have never seen this before. were guessing that the operator is trying to lift to much weight and forcing hydraulic oil the oppisite direction to the fork leveling cylinder and also lifting the boom at the same time and in turn snapping off the yoke ,any insight or if anyone has ever seen this before would be appreciated.
Sticky holding valve. Skytack had the same problem. We were told to run boom up and down with forks curled and dead heading all the way up and all the way down to keep them working and not sticking over time. Curl down and hold curl down while running boom up. Curl up and hold curl up while lowering boom. You can try changing holding valves but without cycling holding valves like described regularly it will likely happen again. You could try calling jlg tech line and see if they have new info on this issue.
Ditto with midnight. We also had alot of skytraks busting the yokes from the cylinders. Had not had one in a while but there for awhile its was happening pretty frequently. It is just a compensation cylinder set up as a master/slave to keep the carriage level through the range of boom lift. Its possible that could be the issue as you mentioned above. But on the other hand we where in a bad spot once with a machine on a job. Mad customer, broke cylinder and no machine to swap it with and could. Mot get a cylinder for almost a week. Pulled the rod out of the barrel and welded the yoke back on. It never broke loose. We eventually ended up swapping cylinder out but it was weeks after the fact. Sooo to that note i dont think i helped you solve your problem.