This is hard to explain to I will do my best. When pilot controls in neutral boom and bucket will drift till resting on ground. Stick and Aux circuit do not drift. takes about 3 to 5 seconds from 6 feet of ground. doesn't matter if pilot shut off is on or off. If I stall out bucket curl, boom will start to rise very slowly. Checked filters and no contamination. My thinking is it may be in the pilot manifold or in the pilot controller. Any thoughts. I'm also going to try some pressure tests and see. This unit is old and has been neglected for a while. Unknown as to how long the problem has ben there.