picked up a project 743 that needs alot of work. i got it running nice but hydraulics were weak. both sides and the loader. i took the vane pump apart to inspect, but should be ok. then i checked the case drain pressure relief valve, it was stuck open i think, so i polished it and put it back together. added oil because most of it ran out. tried to start it but it wont turn far before binding up. i put a wrench on the crank and it goes almost a full turn from stop to stop. it was running good when i shut it down. its outside because my shop only has 8' walls. i dont think there is ice in the fan. i even took the vane pump back off to try turning it over. its a replacement kubota 1903 with unknown hours.port block is mounted on the side, so no brass filter. can something happen in the pumps from loosing that much oil?