I have replaced the axle bearings on my 463F. All 8 bearings were destroyed, but the axles and tubes were okay. You don't need to remove the valve assembly; everything is done through the chain case cover hole. The Timken bearings are available from a bearing supply place, but the seals are Bobcat only. There is no adjustment on the drive chains - if they are loose, you'll have to buy new ones. You won't know how bad they are until you get all the new bearings in. It's not a fun job, but it is doable. You'll need to make or borrow several adapters to remove and install the bearing races. A factory service manual helps, but it's hard to find the information you need.
