Rear Axle Modifications - Axle-Chop How-To

Lots of guys screw up right here. Remember, our goal is to reduce the total housing width from 56.5 inches to 50.5 inches. But because the welded-on outer axle-bearing carriers will be reused, we must remember not to simply measure 3 inches from the outmost ends and chop. Instead, the correct way is to measure in 3 inches from where the axle-bearing carriers meet the axlehousing tubes and make the cuts there. Be sure the axlehousing is resting perfectly flat on the chop saw table for straight cuts. Also, be sure to compensate for the 11/48-inch thickness of the chop saw blade.

After cutting, the bare housing measures 45.5 inches wide, but we still need to reinstall the outer axle-bearing carriers. To guarantee perfect alignment, the Suttons use a bare differential fitted with precision hubs in place of the carrier bearings. The steel alignment bar floats in the hubs and will ensure accurate installation.

The ends are aligned and MIG-welded to the axletubes. After surgery, the total width of the bare housing came out at exactly 50.5 inches.

The severed housing ends are then taken to the lathe, where the welds that bond the outer axle-bearing carriers to the housing bits are removed.

Here's a shot of the cleaned and chamfered outer axle-bearing carrier about to be reunited with the narrowed axlehousing. The chamfered end yields excellent weld penetration. Note how the alignment bar fits through the steel cap bolted to the carrier studs.

Always remember to install new axle seals after surgery like this. The originals are always cooked during the welding process. If you don't have a proper seal-driving tool, a steel tube or socket wrench with 1.700-inch-od will do the trick.

The stock 8 1/4 axlehousing is fabricated from several sections of welded-together steel stampings, but the axletubes are actually pretty beefy at nearly 1/4 inch thick. Though they are swedged into thinner sections where the differential bolts up, Mando says the stock housing is good to 10.99 e.t.'s before it starts to bend, and a welded back brace is highly recommended.

Here's the alignment fixture all set up and ready for action. Before welding, a protractor is used to set the pinion-snubber support at 0 degrees horizontal to the floor. Then each outer axle-bearing carrier end is also zeroed with the protractor before welding as shown. This move ensures that the brake backing plates and shoe assemblies will be level after reassembly. The Suttons can narrow any type of axlehousing. The empty cases in the foreground are used for aligning the tube ends of (left to right) Hotchkis-type Olds/Pontiac, '55-'64 Chevy, 9-inch Ford, and 8-inch Ford axlehousings.

Now what about those axleshafts? Unlike the Ford 8- and 9-inch, Mopar axles are always the same length. The axles that came with the Dodge A100 van measure 30.0 inches overall. As with the axlehousing, we need to remove 3 inches from each shaft, then cut in new splines.