12" x 2" vs 12 and 1/8" x 2" brake shoes. What's the difference?

[Nikkormat]

Earlier I found myself thumbing through the 1972 TSM and found myself in the brakes section. Trying to figure out what trucks got which brakes. Didn't find what I was looking for but I did find this: What gives? The 12" x 2" stuff is hard enough to find what's the deal with this 12 and an eighth setup? Are they a different set of drums and shoes from the 12x2 brakes?

[tgreese]

The 12" x 2" are used with the Dana 60-2 5-lug "heavy half-ton" axle. Parts for these are extremely problematic today. 12 1/8" x 2" are the 8-lug full-floater Dana 60 application, and look to be still available.

[Tatsadasayago]

Yep, unless you are running a J20/J2000 or heavier, the 11x2s are your shooz.

[Nikkormat]

8000 GVW J4000

[Tatsadasayago]

Oy Vey! a REAL truck!
Seems I recall the GM 1 ton pickups from that era used the same shoes.

[Stuka]

GM did use the same axle for a very limited time. I wonder if the D60-2 used under Ford vans use the same pads, or if they switched to the more common D60-3 brakes. Ford used that axle up through the 90's.

[Tatsadasayago]

Weren't the dash 3 shoes 12 x 3"?
I forget.

[Herk]

Also, Wagoneer 11x2 brakes are not a straight bolt-on to the 60-2 axle. Yes, they have the 6-bolt round flanfge so the backing plates bolt up, but the axle shafts stick out 1/2" farther, and the drums are too shallow to cover the shoes. 11 x 2/ 1/2 Ramcharger drums can be made to work by opening up the center register hole.

[Nikkormat]

Weren't the dash 3 shoes 12 x 3"?
I forget.

The 8000 GVW truck has a 60-3 so the chart above applies. It's not the same truck in my signature.

[44bz]

Weren't the dash 3 shoes 12 x 3"?
I forget.

The 8000 GVW truck has a 60-3 so the chart above applies. It's not the same truck in my signature.

That's a curious statement. I haven't seen a Dana 60-3 mentioned anywhere in the TSM...


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[Kaiserman]

Weren't the dash 3 shoes 12 x 3"?
I forget.

The 68-73 Dana 60-3's used 12.125x2 brakes, 74+ Dana 60-3's used 12x2.5" brakes.

[Stuka]

Weren't the dash 3 shoes 12 x 3?
I forget.

The 8000 GVW truck has a 60-3 so the chart above applies. It's not the same truck in my signature.

That's a curious statement. I haven't seen a Dana 60-3 mentioned anywhere in the TSM...

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It wasn't called by the 60-3 moniker. As i recall its just referred to as the full float D60. The 8 lug trucks (ie: J4800) all had that axle.