Had lift cylinders repacked installed them filled with fluid raised bucket went to top came half way down and is now locked. Broke lines loose got bucket back down repeated process same result. tank is full but will only curl. turn machine off turn key over and then bucket will dump if you start it only thing you have is curl. Fixing to pull my hair out Any ideas??
Does sound very strange! Any chance you could have got lines hooked up wrong? Just guessing, does not sound possible that if they were wrong the bucket would go up and not come down. When you try to lower the bucket with engine running does it sound like the hydraulics are under a load? Not a plug or cap left some where that was installed to keep dirt out or stop a loss of fluid? Was going to look for hydraulic schematics but there may be two different versions, one 2ZN1-1749 and one 2ZN1750-up
Wrong lines hooked up on one cylinder will let the boom lift but not lower because the one cylinder has more power extending than the other one retracting. Possibly coming back down it got to the point where the extend and retract forces equalled out. Check your hoses.
Very good point I did not think it completely through! Extending the force to raise the boom would need to be on the barrel end of the cylinders. So I can see that being able to over power the force that would be pushing the other way on the cylinder that was hooked up wrong. Where to bring the boom down would need power to be applied to the end of cylinder comes out of and due to the loss of surface area of the rod it would have much less downward force. Quick calculation for say a 5 inch bore cylinder with a 2.5 inch would give almost 20 square inches on the barrel end and only about 5 square inches on the rod end of the cylinder. So around four times the area on one end than the other end! If someone wants to get all fussy I could look up the exact specs for the cylinder if I had the S/N!
Fortunately Ken the Lift Cylinder Lines are the same whether the S/N is above or below 1750. The Tilt Cylinder Lines however are different. The illustration below may help. I would suspect it's possible that the hoses marked 15 & 16 between the junction block and the lift cylinders are crossed on one side of the machine.