Here's the condensed info for a 1.5 ton heavy and 2 ton disc brake upgrade.
No need to even remove the axle beam from the truck!

If you have a 1.5 ton with the light axle (thread or press in grease caps) or a 41-46 1.5 or 2 ton also with the light axle then first swapping to an AD 2 ton axle beam would be necessary. (Or consider a 41-46 heavy 2 ton axle and double check all the critical measurements.)

In addition to the info below you'd also need to narrow a tierod, this can be done by using the one that comes with the P-30 axle and cutting it approximately 9-1/8" shorter on one end and rethreading it to fit the tierod end again. Consider choosing the right hand threaded end, taps are more common than left hand taps, but left hand taps are available if need be.

The draglink will also need a solution and it should be reasonably simple to assemble from off the shelf ends (different lengths, threads, and tapered ends are available) and a sleeve to connect them, just as the P-30 used. If you have a ball stud type end on the pitman arm you can remove it and have it reamed for a modern draglink end, or can swap pitman arms for one from a newer truck with the tapered hole already. Like this one from a 52 Chevy 1 ton.

Note that if you want to use the original steering box you want a P-30 axle as the donor, not a 3500HD axle with the different steering setup.

Originally Posted by Grigg
...method of adapting the P-30 spindles to the old axle:
...make thin sleeves to press in the kingpin bores in the spindles to adapt them to the original size smaller OD bushings. I'd use green loctite sleeve retaining compound so they stay put, and in the future new kingpins and bushings are an off the shelf item.
A real simple way of making those sleeves is to ream the worn P-30 king pin bushings to proper size to accept the 2 ton bushing, I've done this already and it works very nicely.

The 1.109" kingpin kit you would use is NAPA # 262-1016.
Originally Posted by Grigg
...How wide would a 5/10 lug P-30 or a 3500HD axle (same spindles and hubs)with an AD 2 ton axle beam end up?
WMS to WMS should be 72.8125 within 1/8" or so.
That's 2.875" wider than an original AD 2 ton front axle, or only 1-7/16" wider per side, I can't see any problems with that.
Or better yet look at it another way, it's only about 1/2" wider than an optional NAPCO front axle!

Just for info, I measured 1.5 or 2 ton AD front fenders (on the truck) to be 72" wide inside to inside of the lip at the bottom edge both front and rear of the wheel opening.

Last edited by Grigg; 05/06/2013 2:07 PM.
•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-