Narrow Your Own Axle At Home - 4-Wheel & Off-Road Magazine

Fred Williams Brand Manager, Petersen’s 4Wheel & Off Road

Big tires are often to blame for projects that grow larger and larger over time. For example, if you’re building an old Jeep, a small Suzuki, or even a mini truck and you want big tires (35s or larger) you may soon find that you want larger axles as well. The stock parts are great to a point, but eventually the leverage of big tires, low gears, and locking differentials can take their toll on axleshafts, gears, and housings. A lot of us keep running the small parts to eke out every last bit of use, while others like to upgrade for the security of not having to wrench on the trail.

heat And Beat Barbeque grinding On Axle Housing Photo 35082752

It is most common to find a junkyard axle and figure out a way to swing it under your 4x4 with special outboard leaf spring mounts or custom link suspensions, but what if you want an axle built differently than you can find in the junkyard? If your budget can handle it, a topnotch option is a custom-built axle from such suppliers as Currie, Dynatrac, and Spidertrax. However, some guys who want a custom axle would rather throw down some sparks instead of their MasterCard or Visa to make it happen. We recently drug a junkyard Dana 44 home and chopped, ground, and welded it into a new front axle for a project we’ve been wrenching on afterhours.

heat And Beat Barbeque dana 44 Photo 35960983 We started with a ’79 Dodge half-ton front Dana 44 that we had found on Craigslist. In the end we only kept the housing. We may have been smarter to shop around more, but we had it so we built it.

The Dana 44 we started with is from a late ’70s Dodge half-ton. It has 3⁄8-inch-thick tubes, which is good, but the overall width, the goofy old unit-bearing style hubs, and the lack of locking hubs all made it unrealistic for our project. The job of narrowing and rebuilding our front isn’t for everyone, and we can’t honestly say that it’s better than what those aftermarket axle shops can build, but it will do the job for our little 4x4. It is a fun project, and it was a way of turning a lemon of an axle into lemonade.

heat And Beat Barbeque steering Knuckle In Press Photo 35960986 Narrowing the axle would require multiple steps of measuring. First we had to determine how wide the axle currently is, but this needed to be done with the new Reid Racing heavy-duty, flat-top, cast ductile iron steering knuckles installed, not the old parts we were replacing. We began by pressing in some new ball joints from RockAuto. Meanwhile we spoiled ourselves and sent the axlehousing to a sandblaster to get the years of grease and grime off of it after we disassembled it.

Clearance Considerations
Before you start chopping your axles, consider these points.

• The pinion, driveshaft, steering links, and centersection need to clear other parts like the engine oil pan, starter, and frame at full suspension compression.

• The front pinion angle needs to be set according to front driveshaft joints. A CV requires a different angle than dual U-joints.

• The front pinion wants to move downward under load, the rear upward, especially with a spring-over suspension.

• The suspension you choose will affect the axle you build. Leaf and four-link suspensions move the axle fore and aft. A link suspension with a track bar moves the axle side-to-side through its travel. Also, if your centersection has a cast-in spring mount, you’ll need to consider its angle and location.

• Determine how far an axle can steer with the tires you plan on running so you don’t wind up with tires hitting the springs, links, or frame at full lock by building an axle too narrow.

PhotosView Slideshow Next we assembled a complete Reid knuckle with a spindle and bearings from Offroad Design along with a hub and rotor from Tom’s Bronco Parts. We wanted a 5-on-51⁄2 bolt pattern so we went with all late ’70s F-150 parts from the ball joints out, though you can also use Chevy components. We determined it was 61⁄2 inches from the center of the ball joint to the wheel mount surface. With 533⁄4 inches from ball joint to ball joint, we were looking at a 663⁄4-inch-wide axle precutting. To determine how narrow we could make the housing, we started by measuring the stock axleshafts. We then compared those numbers to a listing of Dana 44 axleshafts available on Superior Axle &amp; Gear’s website (<a href="http://www.superioraxlegear.com" xmlns="http://www.w3.org/1999/xhtml">www.superioraxlegear.com</a>). Our stock shafts were 37.1 and 17.1 inches from the end to the center of the U-joint cap. The shortest options we found were a Jeep Wagoneer short side of 14.69 inches and Jeep Rubicon TJ long side of 31.88 inches. With the selected axleshafts we knew the short side would have to be cut 2.41 inches and the long side tube 5.22 inches. This would leave us with a front axle 59.12 inches wide. We measured the axletube length that would be cut off, including the tube in the C, and then marked the tube all around with a hose clamp for a straight cutline. We also mocked up the axle in the frame of the 4x4 we’re building (see the sidebar “Clearance Considerations”). We centered the axle under the frame, then we shifted it toward the long side axletube an additional 2.81 inches to make up for the difference in cut. This gave us our pinion placement at ride height. After triple-checking all measurements and then writing down the distance from the new endpoint to the cast centersection, we began chopping. First, we used our Miller plasma cutter to lop off the C. We visited a friend’s shop to use his horizontal band saw to cut off the tube at the appropriate mark. A chop saw would also work for this step or even a reciprocating saw or hack saw if you are careful to cut it square. We cleaned the tube ends with a grinder. We ground the excess tube off of the axle C (aka end forging). The C still had a stub of tube in it, so we had to grind all the old weld away until we saw the slight separation line between the tube and the C. Rubbing grinding dust into the cut help it show up. To get the stub of tube out of the C, we made small cuts in the tube lengthwise with a reciprocating saw. This helps release the press fit, but be careful not to cut into the C itself. The tube is easily knocked out with a hammer and punch. You can press the tube out without the horizontal cuts, but it will require a strong shop press. Pinion angle is how far up the pinion points; caster angle is how far back the knuckles lean. We like between 5 and 10 degrees of caster, and try to match it side to side. We decided to aim for 9 degrees of caster with 0 pinion angle to allow us to roll up the pinion slightly while still having good caster. We marked the axletube and C with alignment marks from a punch to assist in reassembly It was time to grill! Not burgers, but end forgings, or axles Cs as you may call them. We needed to heat up the Cs so the metal would expand ever so slightly and slide over the axletube. The professional shops use a press, but we opted to heat the meat—er, metal—up to 400/500 degrees. Our Harbor Freight temp guage told us they were ready. With big gloves and a heavy hammer we took a very hot C and aligned it on the tube with the previously made marks. We quickly double-checked the caster measurement. We pounded it on until the end of the tube matched where the tube had been inserted prior to cutting. One side went on easily without too much drama, but the other side seized up before it was completely on. This required beating it back off, reheating, and then reinstalling, this time with a dab of antiseize for assembly lube. We again double-checked the measurements and caster angle before welding the C on. If you get someone to help you, he can slowly rotate the axle on jackstands while you weld around the C. If not, tack the C in four places around the tube then weld it in sections. Depending on your skill and welding machine you may wish to run a root weld and then a cover weld for optimal strength. The axlehousing is now ready for reassembly, but that will have to be covered in a future issue. Our resulting axle is custom, but not dissimilar to some junkyard axles. Our advice is to always shop around, as you may find a used axle that will work with your project without modification, or a new housing can be built to your specifications by a qualified shop, but if all else fails building your own axle isn’t impossible.