72 C20 3/4 to 1 ton 4 wheel disk conversion

[viking427]

Ive searched the dozens of threads relating to this subject and think I just need some confirmation from knowledgable folks. We're converting a 72 C20 over to 73+ JD8 1 ton 4 wheel disk but want to continue using the stock 16x6.5 8-lug steel wheels and the Dana 60 rear.

If Im understanding correctly;

For the front, we need SRW front spindles/hubs/rotors off a 77 C30 or equivelent SRW. This is the JB8/JD8 brake option that I think began in 1973 with big 1.5" thick rotors, 3 3/8 dia. piston.

Question 1- Will our stock 1969-87 16" 8-lug steel wheels still fit inside the fenders just like the original C20, correct offset etc. with this setup ? Reason I ask is the 72 C20/C30 rotors are listed as 4.76" deep and the 73+ JD8 SRW rotors are spec'd at 5.17" deep ..3/8" thicker. Im assuming the even thicker (7" deep) DRW hubs stick out past the front fenders and require the 19.5" dia. deep offset cab&chassis/RV wheels.

Question 2 - If Im gonna run into fender clearance issues with that extra 3/8" offset, is there another JD8 option, 12.5" dia. x 1.5" thick front hub/rotor that is narrower ? If Im understanding correctly, any 13" or larger rotors require 17" dia. wheels.

For the rear, we'll be running the cadillac eldorado calipers (yeah I know, but for now we need a mechanical parking brake to get it on the road). The Eldo calipers only accept 1.25" thick rotors, so we'll be using 77 K20 slip-on front rotors on this rear disk conversion like everyone else does.

Any comments, corrections, thoughts to all this ? -thanks

[lolife99]

Moved per Op's request.

Can anyone help here?

[viking427]

Bumpity bump - any one tonners 'round these parts ?

[viking427]

Bumpita bump

[nra4life]

Hi, I have a '72 c/20 that has front brakes off an '87 ton van. The rotors are the same and the ton calipers fit the '72 pins. I got ton brakes by changing the calipers and pads. The bores are 3 3/32 instead of 2 15/16. In the rear, I have a 14 bolt from a '90 1 ton pick up. It was pretty direct to put under the truck. I put aftermarket spring pads on the axle housing and stuck it under the truck. The '90 rear still uses SAE threads, so the lines were easy. The brake cables were interesting to hook up, but it works. The stock wheels fit and look right. My next project will be disc brakes on the rear. I expect to use the same style kit you mentioned. Let us know how yours works out.

[Longhorn 70]

I found a kit for the Front at Tuckers. There is a place that has them for the rear named Blackbird's Custom trucks.

I don't know if you want to do the kit route but thought I'd add to save you trouble, maybe.