12" or 12 18" front drum.

[MetalMan]

So I want to replace the front drums on my 69 F250. I measured across the pads and they measure 2 1/2 wide and 12 1/8 across(The old drum measures 12-1/4 x 2-1/2 approximately). I started to look for a 12-1/8 x 2-1/2 drum but no luck. I can find 12 1/8" x 2" or 12" x 2-1/2" but thats it. Would the 12" fit? Do they make a 12-1/8 x 2-1/2 drum?

[68F250]

The standard front drum for the F250 was 12 1/8" x 2", the optional drum was 12" x 2 1/2". Standard front drum for the F350 was 12" x 3". That's all the 8-lug front drums I know of.

[390Nut]

I just measured the original drums off my `69 F100 and they are 11"x3". Seems rather odd that a 3/4 ton would only have 2 or 2 1/2 inch wide front brakes...

[MetalMan]

Well theres an adjustment on the brake assembly so I will go with the 12 x 2-1/2 and pull the shoes in a little. Just figured it seemed a little odd that a 12-1/8 x 2-1/2 would have fit just right!

[68F250]

Paul, actually it's 11 1/32" x 3".

I think 'why" is because the next step up for us was disc brakes.

[390Nut]

Paul, actually it's 11 1/32" x 3".

I think 'why" is because the next step up for us was disc brakes.

With all the rust in this old drum it's more like 10 31/32" x 3"

[flyboy2610]

The size of the drum was also dependent on the GVWR of the truck. The Camper Specials had a #7500 GVWR and got the 2-1/2 wide shoes. The light duty F250"s got the 2" wide shoes.
I don't know about interchangeability.