1-TON Axles for our YJ Rock Crawler Project Rock-Spider

1-TON Axles for our YJ Rock Crawler Project Rock-Spider - 14 Bolt REAR AXLE

1-TON Axles for Project Rock Spider

REAR AXLE

Page 1 - 1-Ton Axles Beginning

Time to get started
First things first. Project Rock Spider had to be pulled from summer fun early and put up on jackstands. It's a tough sacrifice cutting a few months out of summer to work on your rig. None the less I felt it was worth the time and effort to get it done. I of course already started collecting parts prior to starting the swap. The build however was going to be contingent upon the arrival of a few parts. Plenty to do in the meantime. First step was to build a pair of homemade extra tall jackstands along with a pair of lifting jacks to support the Jeep securely while under surgery. (Pictures below)

Homebrew Jacks to support Project Rock Spider during the swap

Unexpected Repairs...
Once everything had been removed front and rear of the Jeep it became evident what other work lie ahead. The front was good to go since only a few years ago I rebuilt the entire front end while changing to shackle reversal & national leafs. The rear part of the jeep needed some attention however. The stock leaf spring mounts were very rashed up and bent from years of abuse. The bolt holes were probably the worst being egg shaped nearly twice the bolt diameter... Resolution: Cut the old mounts off and weld in some new thicker ones semi "frenched" into the frame. This was a sub project I wanted to do while I was here so yes I knew these mounts were toast. Results would be stronger, lower profile, and lower the vehicle an estimated inch. (see pictures)

Possibly a result of baja'ing a rock crawler...

The new setup turned out nice leaving the minimum amount of clearance between the frame & leaf pack. Overall I was able to gain approximately 2" of clearance with the new Heavy Duty mounts.

Spec's
This axle will be equipped with 5.38 gears, Detroit Locker, 31 spline 1.5" diameter OEM axle shafts, DRW Hubs to achieve 63.5" Width (WMS) Large Disc Brakes & Axle Truss. (8 on 6.5 bolt pattern)

14 Bolt Housing Prep Work
Now onto finishing up the 14-bolt so it can be mocked up and ready for installation. This axles been around for sometime so its already been cleaned up and empty awaiting gears, locker & install kit. While waiting for parts to show up I cut about a inch off the bottom lip of the axle in leu of shaving the bottom. This jeep isn't a competitor so if it plows rocks a little no big deal. Next I welded on a beefy truss from Barnes4wd. Constructed entirely of 3/8" steel, this trusses style was my favorite among all the different ones I've seen. And yes its intended for a 3 or 4-link setup but for now it will act as more backbone strength for the 14-bolt housing. This project may evolve into a link suspension later. (All hardware like the spring perches, shock mounts & truss were all from Barnes4wd)

Locker & Gears

With a 14-Bolt you don't get many options for lockers. However we went with the popular Detroit locker which are very affordable. They can be found online for around $400-$450 and sometimes less. One of the other reasons a Detroit locker is popular in 14-Bolts is because they are very simple to install. Simply remove the spider gears and replace it with the locker assembly. Next, put the two carrier pieces together and bolt them all to the new ring gear. In the case of our project, 5.38 gears from Randy's Ring & Pinion.

NOTE: Don't forget to release the lockers retaining bolt after the carrier is assembled.

Continued...
While the axle was getting geared and locked it was also getting a full bearing installation kit I picked up from Randy's as well. Essentially making this axle entirely new again. Unfortunately I don't have every tool yet so the one part of the axle rebuild I did out source was for bearing pressing. I don't have a large press so I had my local parts store press on the carrier & pinion bearings. With the bearings installed it was now time to preload the pinion bearing. This is a crucial step in setting up the gears and it must be set right. (different tolerances if your reusing bearing by the way) The torque is determined by measuring the resistance it takes to constantly spin the pinion assembly. It takes about 350 ft./lbs of torque on the pinion nut to achieve the desired 25-35 in/lbs of preload. I tried using a large vise but under this much pressure it just didn't hold it in place well enough. I ended up bolting the pinion assembly to the axle and binding it from movement while using a cheater bar and a 3/4" breaker. After a few checks on the pinion preload I got it right at 30 in/lbs. Good to go!

Gear Backlash
Setting the ring & pinion backlash was the final step before the 14-bolt could get painted and bolted in under the Jeep. This is were the 14-bolt shines above the other 1-tons. Unlike most axles the 14-bolt pinion is shimmed between the pinion carrier & the axle housing as opposed to pressing the pinion bearing on and off to change shims like you would on a Dana 60 for example. This simply means I don't have to bother my local shop to press & pull bearing for each gear setup. I can do this in the shop with minimal tools and at my leisure. After a about a dozen pattern checks I settled on what you see below. The 5.38 gears were a little tough to setup because the ring gear is so thick that that it actually will make contact with the pinion support bearing portion of the housing. With a little gear setup adjustments it ended up clearing and still allowed for a good contact surface for the gear mesh.

Final Pattern Check, looks good to go!!

Clean & Paint
Now that the gears are setup and everything is torqued to spec the axle was ready for its final cleaning. I used a combination of hand sanding, 4" flapper wheel, 4" wire wheel, and a liberal amount of brake cleaner. I've grown to like using "self etching" or "etching" primer. It has a better adhesion to parts than standard primer. I use it on everything now but the cost is about double per can. This things gonna be a beast!

Spicer conversion joint (1310/1350) enables me to use my current CV driveshaft for now

Axle Shafts, Hubs & Brakes
Now that the housing was mounted up under the jeep it was time to finish putting everything else together. I already had everything painted & ready to go for the most part. TSM Mfg. helped us out with the brake kit. Complete kit includes 12.5" rotors, an array of spacers depending on the application. Stout threaded calipers mounts, calipers w/pads & all the hardware necessary. We went with the non e-brake calipers which are based off a C20 pickup. The use of an inline lever actuated e-brake from Mico lock was going to substitute the e-brake needs. Everything went together smooth and & easy at this point. The hardest part was getting everything painted and ready to assemble. Other pictures include a comparison of the old 8.8 axle shaft next to the 14-bolt.

Extra Stuff
While doing this axle swap I also went ahead and changed the shock mounts from inside the cab to 1.5" shock hoops on the outside of the frame. Its a tight fit but everything clears short of a slight tire rub on full compression. I also built some custom axle wrap bars with kind if a unique style. All constructed of parts I had around the shop. It was pretty easy with the help of my plasma cutter & welder (favorite tools). Last but not least I fabbed up some adjustable bumpstops using 1.25" solid threaded steel, drilled down the center for bumpstop mounting, and some custom mounting cans I'll weld to the frame. This will allow me to easy adjust the overall bump height when tire changes are made. The bumpstop are currently outfitted with stiff 1" poly bumpstops but i've ordered some cushy Timbren's to soften up the impact. (Tech Article in the works)

Page 2
Onto The Front Axle

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