I have a small front end loader on my wheel horse tractor and it lifts slow empty and it wan't lift at all with a bucket full of gravel .It started after I replaced the pump . I have replaced the filter and the oil. It seems to have a self bleeding system but acts like there is air in the line. The hoses are old and could stand to be replaced however they don't seem to be leaking . The loader would lift slow before I replaced the pump but nothing like it is now.