You might be able to swap the brakes off a '55.2 to '59 but the axle itself won't swap. I wonder if the spindles off the later axle might swap onto your '52 axle? That might be worth checking into.
What problem did you encounter considering a 1-ton front axle and brakes? I only ask because I'm close to removing just that setup from the front of a '55 1st GMC setting in my shop.
Regarding the rear, that axle you picked up off Craigslist may be the same Eaton as is stock under your truck. Possibly with a more attractive axle ratio. I have several of those Eaton rears here that have the 5.14 ratio only rock crawlers want.
If you want to come over and look at some 1-ton brake stuff let me know. I'm about 90 minutes from SeaTac (I've made that trip too many times!), so I imagine about the same from Renton.
