The Stovebolt Site Forums The Parking Lot Tons 'o Fun 14 bolt axle swap info

The C&C axle as it comes needs spring pads moved outward a little to match spring center measurement on your old truck.
1948-54 3/4 and 1 ton spring centers measure 41.5" (1.5 and 2 ton with 2.5" springs measure 42")
14 bolt Cab & Chassis spring centers are nominally 40"


The spring pads/perches on the 14 bolt are also for wider springs than the 2" springs the AD 3/4 and 1 ton trucks use.
So may as well remove and replace the spring perches or pads on the 14 bolt axle. Except they're kind of not available for 2" springs and to fit 14 bolt axle tubes.

One option is to harvest the pads off the old Eaton axle, but the 14 bolt has a 3-3/8" axle tube, a little larger than the Eaton, the pads would still need a little grinding/sanding to fit the tube diameter.

I chose to buy new aftermarket fabricated steel pads for the 2" wide springs and still modify the radius to fit the larger 14 bolt axle tube diameter, I used part number 2-Perch from Ruffstuff
Picture attached of what needs machining or grinding to fit.
These spring perches also have alternate holes in them for the spring center bolt, so you can move the whole axle a little back to center tires in the fenders, and or to make the new axle work with the original length driveshaft.

New U-bolts should always be used, they're usually made to match your original (or new length) while you wait at a truck and trailer parts place and or suspension shops, ask around.

You can reuse the original U-bolt saddle under the axle, like the perches it'll need the radius adjusted a little to fit new larger axle tubes.
Picture album of that process, not difficult. https://www.dropbox.com/sh/gz6h467g9uuy5y1/AAApfJp33arW8-7mZSJf0dBBa?dl=0

Alternately I've found that the u-bolt saddles from an early 60's Ford 1 ton (probably 3/4 ton too) is an even better match and takes little if any work to fit the axle tube. These are cast with Ford part number C1TT5796Z
See attached photo of each with dimensions.

Before welding your spring perches to the axle now is the time to carefully consider and set or correct driveline angles, specifically pinion angle.
First read the manuals in this Driveline Set Up tech Tip Remember driveline angles should be checked with the vehicle at it's normal weight.
For reference (check yours) I measure the original spring perches on my 51 GMC 1 ton are level when the pinion is tipped up 4.2° from level. This may or may not be what yours was or needs to be, please READ the Tech Tip!