When I found a screamin' deal on a Dana 70 axle, I jumped on it and stuffed it under my Jeep Grand Cherokee. Unfortunately, the axle came from a 1978 P400 (a parcel delivery van) and had the 0.500" carrier offset (in relation to the pinion gear). This meant that it was hard to find gears, traction devices, and other parts for that differential. It also had 23-spline shafts. When I discovered a leak in the differential housing, it gave me an excuse to look for another Dana 70 and I soon found one. This newer Dana 70 (from a 1996 Dodge D600) has a 0.625" offset, which means that it is much easier to find parts for it. It also has 35-spline shafts and is slightly wider (all the better to improve side hill stability).
I didn't take any pics of the axle when I first got it so the pics jump right into the shaving part. There is a huge lip on the bottom side of the housing from the factory that I decided to remove for clearance's sake. Here you can see what I've marked for removal.
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I used a zip disk on a angle grinder and some sanding pads to smooth it out. The job went very quickly.
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Here's a view from the other side.
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By way of comparison, here's my old D70 with the lip intact.
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The next items to address are the hubs. The D70 is a full floater so the lock nuts will have to come off first.
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I used a punch and a hammer to hit the nuts off since I didn't have the socket for it.
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Once the lock nut and thrust washer are removed, the hub bearing nut must come off next.
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Now the hub is ready to pull off.
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With the hub removed, you're left with the spindle and the drum brake backing plate. I will be switching to disc brakes so the backing plate will have to come off.
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Here's the housing with both ends stripped. Next, I cut off the spring perches. I didn't take a pic of this because I got carried away. Besides, it's pretty straightforward so you don't need any help from me.
I’ll come back to the hubs when I address the disk brake swap. For now I’m off to make coil spring perches.
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I used 6" of C3 structural channel with 1-1/4" of 2-3/4" SCH40 pipe and a piece of 1/4" plate (for the spring retainer).
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Here's the pipe welded onto the C3.
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Here's the layout for my spring mount location. The piece of tape is to mark the centerline of the axle (the right side of the tape is center) then I marked 21" from center on both sides.
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Then I marked 3" on either side of each mark (width of the perch).
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I set the pinion angle, set the spring perch to level, and clamped it in place.
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Then I welded them in place.
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Here is the spring retainer.
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Next I moved on to welding on my lower control arm (LCA) brackets. I used the same technique as welding on the spring perches, mark from center, set the pinion angle and then weld them on level.
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Here's another shock of the LCA mounts.
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And one more. After this, I welded on the 4-link truss. It was constructed of square tube and the tops were capped with flat stock so I could weld on the UCA brackets.
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I don't have a pic of the truss and UCA brackets being welded on so I’m going to use a pic from later on in the build up to show them. (Sorry)
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Now it is on to the hub reassembly and disk brakes. Clean the hub with a wire wheel and degrease the interior to get all the old grease out.
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Then the rotor is from a 79 F250 front Dana 44. It is meant for 9/16" studs, the D70 I have has 5/8" studs so the holes have to be drilled out to fit the larger size. I wanted to stick with the 9/16" studs so that it matches my front axle so I had to get some adapting studs from the parts store. They are approx 5/8" at the top where it holds the rotor and presses into the hub but 9/16" threads. Standard Papco "D" style stud with the part extension 469.
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I loosely placed in all the studs and then began the tedious work of pounding each stud in with a hammer. This was done in a criss/cross pattern to make sure they seated properly.
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Now onto the bearings. First, the inner hub bearing.
This axle is a 1 ton axle but in a three ton truck. So the hub bearings are freakin' huge, twice the size of my 1.5-ton hub bearings that were in my old Dana 70. The hub construction is way beefier in this one too.
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Mmm, big.
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Pack it nice and full with grease and drop it into place.
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Then on to the inner hub seal. Make sure to put a small amount of grease on the inner rubber flap to help it seal/lubricate itself as it slides into place.
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Then press it into place. Once this is done, you're ready to install the hub on the axle (reverse of removal).
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Both hubs re-installed.
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Now its time to weld on the disc brake brackets. I had made these brackets for my old Dana 70 and I don't have any pics of how I made them but I just cut them off the old axle and cleaned 'em up....a bit. I actually only cleaned the paint off them where I was going to weld I didn't strip the whole thing.
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Here they are still attached to the caddy calipers. Anyone notice that the homemade e-brake lever is on upside down? Maybe that’s why my e-brake never worked!!!! Man do I feel stupid. I fixed that now though.
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I set the whole caliper on the bracket over the rotor and used old zip disk (approx 1/16") as a spacer between the inside pad and the rotor. Then very sparingly tacked it in place. It is very important to tack the bracket from the inside facing the hub so the heat will pull the bracket toward the spacer and rotor. If you don’t it will pull the bracket away from the rotor not utilizing the spacer you have and making your brakes not work right. With that done, I pulled the calipers and the hubs off and braced the bracket.
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Make sure to cover your spindle with something that won’t let the spatter burn through and ruin the surface on your bearing seats. That could potentially ruin your axle. When you're all ready, weld her up!
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Time for paint. I ran out of jack stands because my old D70 was sitting on it so I had to use a spring to prop it in place.
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Now I forgot to do this before I painted the axle but it still worked out ok. I had to weld up the breather hole (the 4-link truss was covering it) so I got a 7/16" drill bit and a tapered 1/4" NPT tab then drilled and tapped my housing for a new breather.
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Then I installed a quick disconnect air fitting. I’m going to use one of those coiled air lines for a breather hose.
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Once everything is dry, put the carrier back in. Re-assemble the brakes as outlined above. Put in your shafts, bolt on your cover and run your brake lines. I used the old ones from the previous axle. Bling bling!
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Time for re-installation in the vehicle. Since the axle isn't under the vehicle yet I figured it would be a great time to make some more room in my fenders for where the tires kept rubbing.
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I could use some sort of sophisticated cutting device but I chose a more accurate measure of fender manipulation: a calibrated Pound-O-Meter set on 9 pounds. I started swinging and ended up with this.
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If you've noticed, I didn't mention anything about shocks. I was going to see if I had enough room with the new 4-link truss to do triangulated shocks but I didn't. My rear shocks are too long. Maybe another day I’ll buy shorter ones. In the meantime, I welded the shock mounts on after the axle was installed. Before shocks mounts welded on.
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Shock mounts welded on.
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Well now its done. The wider rear stance is great. My old D70 was only 64-1/2" wide, this is 67". And the new slimmer 4-link truss will make it allot easier to try and fit an exhaust.
I hope this inspires more people to start looking into alternative swaps than the 8.8 and Ford 9". There are so many more axles out there with tons of options!
