I've got a friend of mine's 12E in my possession right now and it doesn't have a sign of foot brakes. The park brake still holds well though. I'm green as to working on grader brakes, and am looking for insight. I don't want to tear it down since it isn't mine (yet, hopefully I can make a deal). But I am wondering what I might be dealing with if I were to aquire it. It needs a good deal of other loving, but it has done fine grading the county road (making up for the shortcomings of the 140M, or should I say, it's seat warmer) but that's a different topic. What do I need to start with and or look for? It's a 99E prefix machine. Any and all help is appreciated. 
 

i would add some dot3 and bleed the brakes. and then look for the leaks??? might be lucky and just need a master cylinder. if the wheel cylinders are leaking you may be able to rebuild them with a new set of cups and seals with a hone. hard part id pulling the center wheel disc off of the axle.

There is some really good information on the 99E in the ACMOC Technical Liberty

I've done a little looking through the parts manual for it in the library. I'll look a bit more. Agree with you bursitis, that wheel center and weight will be a load of fun.