77 c20 'heavy' Brake Drum question

[WALYS60]

Hi All,

New guy here. I’ve been on the 60-66 GMC forum for several years as I’ve been working on my Granddad’s (Wally) 60 GMC. Now my Dad passed last June and my brother and I have inherited his c20 ’77 square body. Ultimately it will be my brothers since I have the GMC but I’m borrowing it until I get the old one back on the road.

Anywho, that is the background. Now to the issue. I drove it 350 miles to my house with very little trouble. The power steering pump was going out but we changed that out without any trouble. Also, the rear left brake would drag and ultimately I lost most rear braking as the back reservoir of the master cylinder went dry. I thought maybe the two issues were related but I identified a leaky wheel cylinder on the drinker’s side and the driver’s side drum is just SHOT. Plenty of pad but at some point in its life it had to have run well beyond pad and probably into springs before it was looked at. The grooves feel like you’re running your fingers over banjo springs.

So here is the question…

It has some ‘rare’-ish ¾ ton ‘heavy’ brake setup on it. It’s the 14 bolt full floating single wheel type, 13 inch (pictured). I have found it on this forum in a few conversations but they were all about converting them. That is AWESOME…and I’m sure my brother will eventually want to do that. However, it ain’t gonna be mine ultimately, and I don’t want to put that kind of money into it! lol. I just want to make it relatively safe and usable. I plan on going to the classic car salvage lot to see if there might be a drum I can use…but otherwise I just plan on doing what, apparently, Dad did and throw some new shoes and wheel cylinder at it and call it good.

The guy at the part store is willing to work with me but we can’t seem to identify it in the system. Is there something I can call it that they can use to find the shoes and cylinder, or would someone have a part number for it, or the internals (shoes, etc)?

Thanks VERY much in advance,
Ron S.