8540 3-point linkage lock

Hello,
Im having trouble with the shaft joining the bottom hitches either locking or jamming on something, which is not allowing the 3-point linkage to lower. My guess is it has something to do with the top hitch sensor for the position control but I cannot find anything in the two manuals I have and was hoping someone may be able to shed some light on the situation for me.
Cheers,
ferg

Hi

If you can lift the arms up by hand and they will only go part way down it could be the roll pin has come out of the "donkey's plonker" on the end of the internal lift piston. This lets it hang down and jam the linkage. If you jack one side up and turn the wheel you can sometimes hear it rattling on the diff. The top cover will have to come off if this is the problem.
Make sure the air solenoid for the lift switch on the door pillar hasn't siezed up before you get too carried away.

Mike

Air solenoid seizing. WD 40 and tap and pull is my guess too. Happens periodically on my 8540. Anything worse and I'd call the dealer!!