I recommend you take the pump to an auto parts store that will send it to a rebuilder. I did this several years ago on my S-470 Satoh Buck about 9 years ago and it cost about $40.00. A new pump is much more. Google the mitsubishi tractor club on yahoo for the vendors with hoses. They can sell you a new pump also if you are in a BIG hurry. The rebuild took about two weeks.