Farmall Cub

I have a loader that will leak down overnight. Either the cylinders or the valve is leaking internal, nothing external. Anyway to tell easily which is leaking, the cylinder or the valve or do i just need to plug the lines and see if the cylinders stay extended?

knowing what kind of system it is would help. If it is single acting, it has to be the valve, because the cylinders would have to be leaking out on to the ground. If it is a 2 way system, raise the bucket and instead of capping the pressure line, disconnect the return lines from each cylinder and fasten it up rather than leaving the end hanging down. Check for fluid coming back out of the line. Not only will that clarify if cylinder or valve, but will tell you which cylinder.

Double acting cylinders. You idea is excellent. I will give it a try this weekend.
Thanks