So backed the hay monster out of the barn the other day, and as it started moving, heard a big BANG out of the back axle. 

Got it moved where it needed to  be, then found rear axle locked up. Jacked it up and what we found was left rear tires were locked up. Once we pulled it all apart, what we found was a broken retractor spring on the brake drum pads.  No worries, we just get a spring kit. 

Not so fast........what spring kit? Truck parts place spent half an hour looking and came to conclusion it would need a Leland K196 kit. This one........

Except the springs in place, and busted one don't match up to the picture.

So in order to try to narrow this down, how does one go about knowing what axle, what brakes and brake drum kit I actually need? Are there any ID numbers to be found anywhere? 

Believe hay monster was built on a Dodge D600 truck chassis, circa 1970, but that is a ballpark year only. Also believe rear axle is same one it left factory with, but no way of knowing for certain. 

I may need an interpreter......as this was my first ever look inside a set of drum brakes like this.....but guys at truck parts place also said it was ALL obsolete and not available......except some of them ARE available on ebay. But you need to know what it is you are looking at, to figure out which kit you need. 

On the Leland kit, there are at least two other "similars" on ebay.......but really none of them look the same as what I'm seeing in this picture. But if you can ID the thing for certain, there are places with NOS to sell. 

Or .........last ditch would be off to a salvage yard to find a truck being parted out. Problem with that is the springs you could get from there may not be much better than what I have now.