Friday, May 6, 2011

Project: Dually Conversion on the Pickup

Taking a brief detour from my rather slow entry of my trip report on the Hoodstock Jamboree to post up the project that’s been really consuming my time for the last couple weeks.

For those that have been following along, I moved into my camper about three years ago, and the camper has gradually gotten heavier.

My urge for travel ever present, I decided it would be best to replace the rear end with something beefier to give me a better load rating and braking margin than I originally started out with.

I spent about a year doing research into the differences between my 3/4 ton HD Power Wagon and the 1-ton dually version of similar year. What I discovered was that in those years the 1-ton drive train, frame, brake master cylinder, etc…. was identical between the 3/4 ton HD and 1-ton. The only major difference was axles and brakes under the units.

So, the next step was to round myself up an axle. This took up a decent amount of time and I was beginning to think that it wouldn’t be feasible to find one I could afford until one proverbially dropped in my lap.

A friend of my brothers was moving out of his home and needed to get rid of some old project materials quick. He had the rear end of an old motorhome sitting around that he was going to convert into a trailer, but never did.

In desperation to get rid of it, I bought the axle (A Spicer 70HD) for $75 and my brother brought it home, complete with the original 16.5” rims with period Dayton Thorobred tires on them.

Axle as it was when it was brought homeAxle as it was when it was brought homeP1090793

Dayton ThorobredDua-Load Super EMTs

It took several more months, mostly because of financial constraints, to take the axle to the welders shop to have the old motorhome air bag mounts and shock mounts removed and the spring perches repositioned to fit the truck. Backing plate to backing plate, the axle was the same width as the Spicer 60 currently on the truck, so there’d be no clearance issues.

Then, the axle was disassembled and all the seals were replaced and the brakes completely rebuilt.

Finally, over the past two weeks I got enough dry weather to put the last of the pieces together and install and perform the final reassembly of the axle.

Original Dana 60 Axle from the truckOut with the old…

Spicer 70-B Ready for installationIn with the new!

With the help of a friend, we unbolted and pulled out the old Dana 60, set it aside and then spent about three hours getting the new axle into position and positioned properly back in place under the leaf springs.

Suspension waiting for axleSpicer 70-B in place and new brakes assembled

We had to stop and wait till the next day to take the U-Bolts over to Salem Offroad to buy new ones, two inches longer at price of $14 apiece.


It was worth it Smile

Spicer 70-B Bolted in place, completely reassmbled

Checking out the spacing to make sure the tires I’ll be ordering later this week will fit without rubbing.

Rims in place for measurements

Checking to see how far the wheel comes out beyond the body of the truck….

Outer wheel comes out about 6 inches past body

Making this project work took some ingenuity on my part, one big one was solving the shock mount issue. In the late 80s to the early 90s, the clamp bracket that secured the axle also doubled as the shock absorber mount. However, finding one that would fit would have been next to impossible, as these first generation are rather rare.

My solution?

Use the original clamp brackets that came with the axle and abut the newer D60 brackets underneath, they fit together just like a glove Smile.

Bracket closeupView of spring pack, new ubolts and brackets

The trade-off of using this method is the shock mounts are roughly an inch further down, but the shocks have a decent amount of extra length in them that it shouldn’t be an issue.

Underside of the truck, still some finish work todo

As you can see, I still have some finish work to do, but with luck next week, I should be able to take my first test drive with a dually truck!

I still have more to do, clearance lights to add, fender flares to install, but the big hurdle is cleared, the rear end is installed without any serious hiccups.

Keep an eye out, there'll be more later as I wrap up this project.



  2. Thanks, been watching for one, but the few I have found are too far away to make buying them affordable.

    So far, getting some 7" fender flares looking the best option.

  3. Matt we had a camper for year,don/t be cheap on
    tires i found out the way!!!!