Builds ‘68 M715, AKA "Smokey" (Can I post this Jeep on MUD?)

[Cabelln1]

ROCK40 -Im interested in what the specs are on that rear dana 70 you are not gonna use -if its still available what is the WMS on it? Curious if you could have kept the 70 and the dually 60 front and ran a wheel with more backspacing if you could have gotten the same results?

 

[Rock40]

I still have it, the WMS on the 70HD is 73" if you run the stock 70 hubs. The plan was to use 14B hubs which narrow it by 4.25" overall. With the 14B hubs it's a pretty close match to Dana 60 WMS.

It came down to a toss up with the axles, tires and backspacing on the wheels. We definitely could have kept the 70HD but in the long run we wanted to narrow the truck as much as possible AND have maximum steering AND run common 17" tires on common wheels. The other option was H1 wheels but being stuck with 16.5" tires isn't ideal. At least for what we want to do here. Also could have run fully custom wheels with custom backspace but again the idea is "off the shelf parts" for as much of this as possible.

 

[Rock40]

Starting the tunnel construction, all 14G

 

[Rock40]

I’m using 1/4-20 threaded nutserts

 

[Rock40]

Let’s make a 15 Bolt....

 

[Rock40]

All done on a mill to keep it level

 

[Rock40]

Better, much better. This is the 15B kit from East Coast Gear Supply

 

[boots4]

That's a nice looking shave kit. Doing that mill work will help if fit just right.

 

[Rock40]

I must have woke up hating myself because I ended up hand lapping the 15B cover 3 hours this afternoon just to get the damn thing flat.

It looks like it snagged in the mill when ECGS tried to flatten it. Pretty big gouges

Here we go...

60 grit paper glued to a 3/8” flat plate

Getting closer...

Still low in 2 corners

Done. It’s for sure flat now.

 

[GLTHFJ60]

Now that's attention to detail.

 

[74fj40]

Looks good. Do you have to turn down the ring gear at all?

 

[Rock40]

Now that's attention to detail.

Haha, it reminded me of the short time I worked in an industrial valve shop servicing stuff for a local refinery. So tedious.

@74fj40, yeah the ring gear has to be cut down 5/16” but TMR (who makes the most popular shave kit for the 14B) will do it for $45. At this point, I don’t even have the 4.56 gears for it yet but that’ll get shipped off once I do.
Planning to do the Ballistic shave kit for the D60 in the next few weeks and a few other small machining projects

 

[GLTHFJ60]

If you've got a mill, surely you've got a lathe. Carbide would chew up that ring gear.

 

[Rock40]

If you've got a mill, surely you've got a lathe. Carbide would chew up that ring gear.

Yeah, the issue is machining the ring gear when you get to the edge of the teeth. The cutter hangs up and is really prone to breakage. If TMR will do it for $45 then good on them, maybe they're grinding them then cleaning the cut up a bit? Not sure

 

[cruisermatt]

theres CBN and ceramic cutters designed for interrupted cuts just like that... need a very rigid machine as well

 

[Cabelln1]

I sent you a message about the rear 70

 

[Rock40]

I sent you a message about the rear 70

PM sent

 

[Rock40]

Time to get busy with the D60....

Full tear down, these are the parts which won't be reused on this build

Lower trunnion bearing caps were COMPLETELY frozen in the knuckle. Bearings looked OK though. Because I couldn't get the lower caps off, I had no choice but to remove the kingpins first.

Tried with my normal 1/2" impact....no go. Went to my 1" impact which is an Ingersoll Rand and I think is nearly 1,000ft/lbs of torque. At 120 psi they didn't budge. Since the axle isn't secured into anything, I couldn't put a 12' cheater bar on it.

So....used a CO2 Powertank and gradually kept increasing the pressure. One broke loose at 300psi, the other at nearly 350. Yes, dumb, tools blow up but frankly I was out of options. Once the knuckle was off, I was able to knock the trunnion caps off very slowly through the knuckle assembly

AK truck, the tubes were both pretty friggin' nasty.

On the way to the blaster...

 

[Rock40]

And now it’s clean. No kidding this took them only about 10 minutes. I could have spent HOURS on it and it wouldn't be this good.

Inside the axle tubes. I asked them to shoot a bunch of media through them and they did a great job. No more rust, dirt or scale.

However, the previous damage on the long side (driver) tube is pretty evident here. the U-joint wore into it pretty deep, I'd suspect a failed spindle bearing or broken axle.

The axle looked like it had been fully disassembled at some point. The main seals at the carrier had been replaced and someone had smeared blue RTV all over them. The differential itself was very clean though

 

[Rock40]

Time for a shave.... this is the Ballistic Fab D60 shave kit and the cover is sans "skull" plate. Gain in clearance is right around an inch. Worth it? In my opinion yes if you've got the axle down this far, have it blasted and are going to change/replace EVERYTHING

Back at the mill, working on clean stuff is SO nice.

The cast steel mills well and this made LOTS of chips.

Here's the end result. Compared to the 15B shave kit, the axle is opened up a WHOLE lot more here. Like a told my friend Mark (owner of this build) we are taking a highly sought after D60 and essentially ruining the perfectly good factory casting. I love it.