If you are going to the trouble of upgrading the brakes on your C10, you are more than likely going to want to have matching wheels on the front and rear of the truck. Since the upgrade to the front from stock drum brakes to disc brakes in the accompanying article changed the bolt pattern from six lugs to five lugs (5-on-5 bolt circle), it's necessary to address the rear axles in order to have matching wheels. You have a couple of options in how to go about doing this. To keep your existing rear axle housing, you can change the bolt pattern by replacing the axles (and brake drums) with new ones in the bolt pattern you need or you can have the axles and brake drums redrilled. If you choose to have the axles redrilled, you should install new wheel studs, rather than reusing the old wheel studs.

In either case, you will be required to remove the axles from the housing. To do this with a typical GM truck rearend, jack up the truck and secure it safely on jack stands if you are not using a garage lift. Put the transmission in neutral, as you will need to be able to rotate the gears in the differential. Place a drain pan under the rearend cover and then loosen the cover bolts enough so that the gear lube drains out of the rearend. While the gear lube is draining, remove both rear wheels. When the gear lube has drained out of the differential, completely remove the bolts securing the cover and set the rearend cover aside (letting it soak in a parts cleaner would be a great idea). Now remove the cross-shaft retaining bolt and then pull the cross-shaft outward. The cross-shaft does not need to be removed completely, just enough so that the axles can be pushed inward. When the axles are pushed inward, the axleshaft C-clips should fall right out. The axles can now be pulled out. After pulling the axles out of the housing, inspect them for wear or other damage.

If you choose to replace the axles, you will first need to determine the axle diameter, axle length, and number of splines, and then find suitable replacements that have the desired bolt pattern. Unless you are able to purchase new axles that meet your specifications, you will need to verify that any candidates for replacements are not bent or otherwise damaged in any way that would make them unusable or short-lived.

If you have access to a machine shop that routinely redrills axles and brake drums, this is perhaps your best bet, as you already know that the axles are the correct size and will work. For our '68 C10 project, we chose to forego the salvage yards looking for axles, and went straight to B&D Fabrications to have the axles redrilled. The intent was to have the brake drums redrilled as well, but there were already several holes in the existing brake drums, so those were replaced with new drums. After Brian Elbert at B&D Fabrications does his magic on the axles, they can be reinstalled.