i bought an old pc300 to build a road up the side of the mountian in colorado. it runs like a top, tracks straight and feels pretty good considering the age. but the curl on thew bucket is weak. i can dig and when i curl it just seems to do nothing unless it pretty easy digging. i can make it fall back when i am raking with it. is there a relief valve on that circut that is bypassing? or maybe the cylinder just leaking by?