Hey guys, the time has come to fix the brakes on my 450 LP, it hasn"t had any for three years, and the time has come to tackle the obvious. The tractor sat up for 22 years before I got it running again, and as far as I know, the brakes didn"t work the last few years my family had it....yeah, dangerous, I know. My question is, what is considered to be a safe beginning amount to mill off the castings that cover the brake discs? The discs themselves look pretty good, so I"m thinking that the castings need milling, but having never done a brake job on a Farmall, I"m a little in the dark. Any recommendations for how much to have milled off? Thanks, Hugh

Best way i have found was to take and get all your new parts and place every thing in the brake drum and use a straight edge and see how much clearance ya have then take off just enough so you have about 1/8th clearance .

Okay, thanks, now for a follow-up question:Besides the five bolts, is there anything keeping the brake drum on, other than rust or a ridge on the splined shaft? Thanks.

No (linkage out the hole!!) Jim

I just did mine on my F300, and one side was very rusted. I took all the parts to a machinist and had him mill the inside brake surface in the housing flat, and mill the two actuator discs brake surfaces flat. The brake surface on the rear end housings only needed .005 milled off to clean them up.
I purchased new brake discs (4), balls (6), and springs (4).
Now watch it on the springs, some have the openings on the same side, originals were open at 180 degrees, these are the ones you need to purchase. I tried the first ones with the openings (hooks) on the same side and had no luck with them as the brakes kept binding.
Clean up the inside ( where the balls go) of your brake actuators via media blasting or rotary wire brush, pay particular attention to the ramps the balls travel in. These must be clean with as little material removed as possible. Mine were not pitted, and cleaned up well with a wire brush, I then used emery cloth to polish the ramps shiny and used copper never seize to coat the new balls & ramps, once you have the actuator halves assembled, with the new balls & springs, take your brake housings and lay them on the work bench.
Install the first brake disc. Check to be sure the actuator is fully compressed, and the balls are fully seated in their pockets.
I measured mine with a dial caliper to be sure the measurement was pretty close all the way around. Now install the assembled actuator and the other inside brake disc. Place a straightedge across the mounting face of the brake housing and measure the clearance from the straight edge to the top brake surface.
I have found .030 to .040 is about optimum for the clearance.
The difference is how much your machinists need to remove from the outer housing surface to achieve the .030 to .040 clearance. Any more than that the brakes don't work as well as they should, any less and they stick & grab and you always have to back up to get them to release.
There is a large oring that seals the inner brake surface to the rear end housing, you will need 2, and a seal that goes on the pinion shaft you will need 2 also. Check the teeth on the pinion shaft the brake "pads" ride on. If they are very pitted or worn the brakes will stick no matter how much never seize you use.

Thanks to all for the replies and expertise, especially to rhtx55 for the detailed explanation of what to do and watch for....we'll see how long it takes me to get this finished! Hugh