Case 580SE Parking Brake, Friction Disk, Counter Shaft Spline Wear

[Buick455]

I bought a 580SE 2WD and one issue I have if that the trans-axle counter shaft splines are worn where the parking brake friction disk is located on the shaft. I bought this backhoe from photos and I knew the brake assembly was missing so I purchased all new parts to install the brake and had a feeling the splines maybe worn which they are. The disk fits snug on the splines until I push it all the way on which is where I assume it should be located and that's where the splines are worn. The backhoe is at my other farm so I did not have much time to mess with it but if the disk is moved outward where the splines are good it will interfere with the driveshaft u-joint as there is very little room between the disk OD and the drive shaft. If I had another disk I could make a hub and weld it to the new disk which is probably how it should have been designed in the first place. I may also be able to turn down the new disk to clear the driveshaft and move the entire brake assemble out some. Replacing the shaft is not an option as it would entail rebuilding the trans-axle which is otherwise in good shape.
If anyone has delt with this before or possibly has a used disk with good splines, I would be interested in it as they are over $360 new.