I have a B6000 with the K44 mower which uses a lot of the same parts as the K48. Note that it makes a difference whether you are talking about the center spindle or one of the outboard spindles. Seals, bearings and other components are available from Kubota at not too unreasonable a price. The shafts and housings, however, are no longer available. If you go to a on-line dealer (like
https://parts.mbtractor.com/ or
www.colemanequip.com) you can look up the parts (you may have to use the K44 parts diagram under "turf equipment"). The parts list will refer you to a replacement part number for the shaft, but that part number won't work with your original housing (blade will end up at a different height than other blades). The is an entire spindle assembly from another model that will work, but your talking several hundred $$$.