Im condused... the P30 has larger than 1.109" kingpins.
Nothing I know of has 1.109" kingpins and disc brakes.

What are you trying to do?
Did you checkout the disc brake sticky?

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
---All pictures---
"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-