Cat e120b hydraulic bleed off HELP!!!

I have a old cat e120b machine... its an old hoe but dependable. Recently after pushing its limits handling large stumps the mainstick cylinders will bleed off fairly fast. If it doeant have a load in the bucket i can bump the controls to get it to stay in place... leading me to believe a control valve blown o ring possibly? Cylinders are dry just scratching my head on it and like having the machine around. Any help appreciated

Cat e120b hydraulic bleed off HELP!!!