60-66 K20 rear drum brake info needed

[Short 3/4]

I am looking for any pictures/information/parts sources for the 12x2” rear drums on a K20

While there is much information on the 1/2 ton 4x4’s and 2wd 3/4 tons, unfortunately the 12x2” drums on the K20 are a completely different animal. While some vendors mistakenly show crossover of some parts, there is NO crossover between K20’s (front or rear) with any other truck models (other than rear hub bearings, which are the same as a 3/4 ton 2wd).

My main questions are:

When did Chevy switch from slip fit to press on drums in the rear? I’ve seen slip on drums on a 64 and press on style on a 66, but can’t find any definite info on when this changed.

Did the drum stay the same and the hub was different between the two styles, or was the drum also different? LMC shows the same drum from 60-66, but they are not always a reliable source of information.

Are the rear brakes the same on a Chevy Eaton style rear as on a GMC Dana style?

Did the rear brakes stay the same on the 67-72 K20’s?

Any information and especially pictures of what you have would be great. I know there are others out there with some of the same questions.

Thanks,
Tom

[raylube]

I don't have the answers but I did buysome new drums for my Eaton axle for my k20 but didn't use them as I swapped in a 14 bolt and now I am stuck with the drums and can't return them.

[57taskforce]

D60 and H052 do not use the same brakes. I don’t think any of the eatons used slip on drums. They were like the majority of the 14 bolts with the drum pinned between the wheel studs and hub. Some lighter GVW Dana 60’s did have slip on drums I believe.
Brake equipment in these trucks was likely based on GVW and other options like heavy duty springs when the trucks were ordered I’d guess. It’s not like the square body and later trucks where you could order specific brake packages like JB6 and JB8 etc.

[Short 3/4]

Thanks to both of you for the replies.

I can verify that early K20’s definitely came with slip on rears, as my 64 parts truck had a full original set that unfortunately got lost in the long restoration process. I also found some early 12x2” slip ons from what I believe was a 50’s era 2wd, and a 12x2” press on assembly from a 66 K20.

Interestingly all three of the above (Eaton) 12x2” brake assemblies used the same drums, but different hubs (the drums can be separated from the press on style, it’s just a PITA).

Raylube, what year is your K20, and what style rear drums did it use? If you are getting rid of any parts after your swap please let me know as I might be interested in purchasing them.

Thanks
Tom

[Short 3/4]

So now I (think) I’ve verified that the hubs are different but the drums remain the same between different years. The question is: what trucks used the hubs I’m looking for…and of course, where to find them. And even though GMC never used an Eaton rear, I’ve heard that the D60 stubs are basically the same, so maybe some brake parts (like the hubs) might interchange?

I’m now using the 66 and up style press on drums, but really want to convert back to the early slip on type.

Any tips, leads or pictures would be greatly appreciated,
Thanks
Tom