Thanks for taking the time to put down all of this great info
@nitro_rat! As always, I'm learning a ton.
We're on the same page as far as drum brakes go, it seems like most folks are totally overwhelmed by what they don't understand when it comes to servicing/adjusting drum brakes which is what gives them a bad rap, but I've found that once you understand how they operate, the mystery is gone and they work well when in good shape, like you said. I've been lucky to get a good education on drums since up until recently, all of my family and friends' vehicles had rear drums and sometimes front drums (in the case of a '58 Nash I helped do a full mechanical resto on and a buddy's '66 Plymouth Satellite at first) and no one ever wanted to touch them, so I'd volunteer and the first couple sets were a learning experience but after that I don't blink an eye. I actually really like drum brakes. Like you highlighted, in the past I've made the mistake of using too much "brake grease" to my detriment. ? I keep it light now!
Thankfully ol' Edger is ABS-free from the factory, so I don't have to go down that road! Good to know about the adjustable proportioning valve though, I'll keep that in mind. I installed one of those on the rear drum circuit of my buddy's '66 Satellite after we rebuilt the rear drums and swapped the front disks for waaaaay-overkill Wilwood 4-piston units. It was super nice to be able to dial the rear drums in to be copacetic with the race-car front brakes. ? The current brake fluid in Edger could be a prop stand-in as "bubblin' crude" in the Beverly Hill Billys TV show intro, so a proper bleed to get all that riff-raff out is step one.
On GMT400.com and other sites I've read about the GMT800 master cylinder swap, and it didn't make much sense to me and there were always seemingly holes in the info I was reading, so thanks for clearing that up! If I was to take another WAG, I wonder if the bore sizes different on the GMT800 master cylinder? That's the only thing I can think of other then if the pedal/push-rod ratio is different that would make people claim a big improvement over the factory unit...
Copy that on the hydroboost, good to know and I'm sure its only a matter of time until I do that swap. I'll start with the the larger rear drums, dually 1-3/16" wheel cylinders and larger-piston 3/4/1 ton calipers up front with the factory vacuum booster and see how it feels with fresh rubber brake lines and fluid first. Then I'll keep my eyes open for a junkyard hydroboost setup.
The hydroboost sounds like a winner to me because more frequently as the years pass, I find myself towing rented double-axle car trailers (From U-Haul mostly as its the only choice around here to rent a trailer) with 3-4k pound cars on them. Figure, the car trailer weighs around 2,250 pounds unloaded with an average of a 3,500lb car on it, it's pushing 6000lbs, so the best possible brakes are a must, especially on a shorter wheelbase rig like this. I certainly don't tow loaded trailers like this fast (usually 4th gear on the NV4500 at 55-65mph depending), but when all the upgrades are done, it should be identically equipped like a F44 K1500 or LD K2500.
Good to know about the rear disk and possible GMT800 front knuckle upgrade. Even though it's awfully tempting, with a relativity new set of 16" BFGs, I'll probably stick with brakes that will fit under the 16" wheels.
Thanks again for all the info!