Project Master ‘Kee: ’89 Jeep Cherokee Build, Part 2

Jul. 13, 2011 By Jim Brightly

Email
Print
Discuss

We’ll be installing G2 4.56:1 ring and pinion, G2 axleshafts, ARB air lockers, and new bearings, seals, etc. in the Master ‘Kee’s Dana 30 front differential and AMC Model 35 rear differential.

Master ‘Kee is a play on the words “Cherokee” and “master” of the Arizona trails. To remind my faithful readers (since it’s been a while since segment #1 of Master 'Kee was published): Our theme and final goal of the project is building the ultimate camera car—a four wheeler that can cover any off-road event, ease over any trail this side of the Hammers, and comfortably prerun any off-road race.

This is an outline of what we’re planning. We’re using a 1989 Cherokee XJ model because it’s an extremely capable vehicle right out of the Jeep box, and the XJ we’re using is equipped with the 4.0L in-line EFI six-cylinder engine and a four-speed automatic transmission. It has a Dana 30 front differential and an AMC Model 35 rear differential. Plus, because XJ prices are coming down, they’re becoming very popular with first-time four-wheelers. How do I know this? Because my Jeep Creep question-and-answer column receives more Cherokee technical questions each month than questions about other models.

As mentioned previously, this build will be a multi-part series of articles. These articles are aimed at first-timers—folks who haven’t rebuilt a four-wheeler before—to show them what can be accomplished on these Jeeps. It’s important to mention here that similar products to those being used in this series can also be installed on any other type of Jeep—or any other four-wheeler—only the specific installation instructions may differ slightly.

First task to clean up the differential—inside and outside—before installing anything.

We also want to take the time to thank all of our sponsors. I’ll be listing all their websites at the end of each segment—even if their products don’t happen to appear in that segment. While I’ll be listing all the specific websites, virtually all the products used on Master ‘Kee are available from 4-Wheel Hardware (http://www.4wd.com/), which worked quite closely with us on this project. 4WD has one of the most extensive catalogs of four-wheel-drive products in the industry.

G2 offers complete sets of gaskets, seals, and bearings for every popular differential being used in four-wheelers.

This multi-article series will continue next month in Segment #3 with the suspension installation; however, this month we’ll completely rebuild the Dana 30 (front) and Model 35 (rear) differentials with new seals, bearings, etc. We’re also installing new axles and changing the OEM gear ratios to 4.56:1 gears; axle shafts and the ring-and-pinion sets are from G2 Performance (http://www.g2axle.com/). While we’re covered with gear oil, we’ll also be installing ARB Air Lockers (http://www.arb.com/), and then (next segment) we’ll protect all those new goodies with high-strength aluminum differential covers from G2 and shop-made axle trusses and differential skid plates. As you’ll see in this segment’s photos, all axle and differential work is being done by the Rock Lizard shop of Kingman, Arizona.

In an AMC Model 35 differential there are no return passages for the gear oil, which lubricates the axles and bearings so a channel will have to be ground into cast bearing housing.

Building a differential—almost from the bare axle tubes and center pumpkin—is the work of an expert, and a very experienced expert at that (not just an inexperienced but well-trained novice from a tech school). In addition to requiring an experienced technician, differential work requires several specialized tools. What I’m trying to say is this: While the ARB instructions on installing their air lockers are among the best I’ve ever worked with (if not the best!), you’ll also need a tech that’s very familiar with ARB installations to assure that there will be no callbacks or unexpected breakdowns on the trail.

Also, I will not be showing you how to install the ARB air compressor with which most ARB air lockers are controlled. We made a decision early on to use the Viair system, which includes onboard air pump, air lines (with glad-hand connectors on each bumper), and a metal air bottle holding a reservoir of high-pressure air. The reservoir will allow us to use air tools, Hella air horns, control the ARB air lockers, and quickly refill our tires. We will, however, be using the ARB switches. The air system will be shown in a later segment.

Just a slight groove in the location shown—on both sides of the pumpkin (see page 12, instructions)—will allow gear oil to flow back into the pumpkin from the axle tubes without creating an overpressure problem.

In this I speak from personal experience. My first two Jeeps with ARB lockers had to be repaired at the Rock Lizard shop because the initial installations were done by inexperienced techs. Very experienced differential mechanics but inexperienced with the ARB units. After many years and miles on the Jeeps, no more problems.

Although many mechanics miss this step, the Rock Lizard shop always hones down any possible burrs, rough spots, etc., on each ring gear it installs.

One other tip—also from personal experience—always try to be stopped when you engage the ARB locker. ARB does not include this tip, I’ve always tried to follow my own advice and I’ve had no problems with any of the four ARB lockers in the two Jeeps.

Project Master ‘Kee Sponsors:
4-Wheel Hardware (http://www.4wd.com/)
ARB Air Lockers (http://www.arb.com/)
Bestop Products (http://www.bestop.com/)
Cobra Electronics (http://www.cobra.com/)
DJ Safety (http://www.djsafety.com/)
G2 Performance (http://www.g2axle.com/)
Garmin nuvi 1450 (http://www.garmin.com/)
Garvin Wilderness Products (http://www.wildernessracks.com/)
Goodyear Tires (http://www.goodyear.com/)
Hella (http://www.hella.com/)
Raceline Wheels (http://www.racelinewheels.com/)
Ramsey Winches (http://www.ramsey.com/)
Skyjacker Products (http://www.skyjacker.com/)
Sylvania (http://www.sylvania.com/)
Viair (http://www.viaircorp.com/)

A 7/16” hole—squared to the housing—must be drilled in the Model 35’s pumpkin for bulkhead port (see page 18).

Rock Lizard usually does this in two or three steps in bit sizes.

The hole must then be tapped with a ¼” NPT pipe tap. Do tap all the way through the bulkhead, though, because the fitting is tapered so you’ll want to leave a thread or two blank so that the fitting seals tightly.

With each ARB kit is everything you or your mechanic will need for the installation.

ARB always provides an air tube that is much longer than necessary. Assemble the air locker and ring gear to check the pinion’s setting. Note the line of small scratches along the locker’s surface.

We applied marking dope to the pinion gear to better show what ARB is talking about on page 20.

The marking dope clearly shows the “lightning” scratches on the locker’s surface. The pinion will have to be ground down slightly to eliminate these scratches.

The pen indicates where the grinding has to occur.

Only about 1/8” of material must be removed. Just make sure the surfaces are thoroughly cleaned after the material is removed.

Use a nonmetallic tool to assist in the bending the air tube. It’s a fairly brittle material, so be careful not to crack it or an air leak will result.

The air tube must be bent away from the bearing cap so that it won’t rub and wear.

Make sure the tube is the proper length and then cut it with a tube cutting tool so that it won’t be crimped.

Instructions Figure 19 (page 26) gives you a cutaway of how to assemble the air tube fitting.

After cutting the air tube, route it through the drilled and tapped hole.

With three or four wraps of plumber’s tape for sealing, tighten the fitting in its hole.

Make sure the O-ring is in place in the bulkhead body. The O-ring seals the compression nut to the bulkhead body.

$Although it’s hard to see, there’s a slight fracture in the copper tube, which happened when the tube was being bent. The crack will be brazed before the assembly is completed.$

In prepping the axle housings for the axles, use Assemblee Goo (spelling is correct) to hold the spring (which holds the rubber seal against the axle) in place while tapping the seal into place.

The axle end bearing is tapped into place first.

Use a bearing tool to seat the bearing.

After seating the axle end bearing, seat the axle seal.

If you’re not going to insert the axles immediately, use clear shipping tape or Saran Wrap to complete seal the axle housing from dirt and debris.

Using marking dope and a micrometer, set the ring and pinion gears. This must be done by an expert or excessive wear or premature breakage will occur.

The AMC Model 35 is a C-clip model. Remove this cross shaft retaining pin (page 38) from the air locker housing.

Remove the long cross shaft.

Insert both axles fully into the housing and gently tap them in as far they will go (page 39). Use needle-nosed pliers and insert the C-clips (pages 39 and 40).