Mitsubishi MT372 Hydraulics issue

[kempfat]

I am having an issue with my hydraulics. The 3pt hitch is locked in the raised position and it will not go down. I have tried everything that I can think of to include: Draining the fluid and checking the filter screen, (is there supposed to be a spring in or on the filter screen? the sticker on the fender mentioned a spring but I did not see one.) (even with no fluid and air in the lines it did not go down), refilling with fresh universal tractor hydraulic fluid, draining the air out of the system, adjusting the speed control on the area below the front of the seat, and checked the hydraulic pump by cracking each seal one at a time and bumping the key for each (NOTE: Do not squat down directly in front of the out side of the pump and have someone bump the key... You will be covered in fluid! Lesson Learned

On a separate note, where can I find solid rims for my front tires? The split rim 3 bolt pattern that I have are ridiculous!

Thank you so much for any assistance!