Got a root grapple on a FEL that sometimes the claws don't want to open. I'm using the rear remote to operate. It doesn't do it all the time but when it does I move the lever back and forth several times and it eventually works. One hose jumps when moving the lever so I know it's pressurized. Fluid level is fine.Any ideas

John Deere tractor with the loader hooked into the rear remotes controlled by the joy stick? Mine does this too. The plastic actuator that moves the levers down in the joy stick is wore out. It'll break eventually and you'll have to replace it.

is this a manual lever operated valve or an electrical control valve? if it is a manual spool valve, you can take that stack valve apart and clean it, possibly has debris that isn't letting the detent inside operate correctly. or the detent is worn out.?

Kubota m7040 connected to rear spare remote. Tractor has very low hours and has never had anything connected to the spare remote until the grapple.

You probably have a sticking check valve in your remote quick couplings. I know of no way to check except to replace the male and female quick couplings one at a time until it works every time you pull the lever. In other words buy one male and one female coupling and start replacing then one at a time until it works every time. use the one that you took off if it is still sticking on the other remote until you find the bad one.