Change bucket seals and bucket still seep down

Hydraulic systems, if you were to plug the return lines off the bucket pistons you could test the actual pistons inside the assembly. Raise the bucket and see if the bucket still falls, dont lift it to far or you will have a lot of hydraulic fluid to clean up, you might also have got the wrong kit and the seals are not touching the sidewalls of the cylinder. If the bucket stays in place then you have a leaky return stuck on and releasing the pressure.

Seals are gone in pump and allowing flow back into holding tank if it is not seeping onto the ground