I have a dayton 12 ton cherry picker. It has a problem lifting. I do not have any load on it right now but it does not want to go up. I pump the handle and it goes up once but will not go if i pump it again. If i wait 30 minutes or so it will go up one more time then i have to wait again. I put my shoulder under it and got the pump cock eyed and it worked fine. But when i put it back into the base it acts up again. does it need fluid and if so where do i put it in? thanks guys.