Rubicon Express Brackets

I picked up a reverse rotation D44 front axle out of a mid to late 70's fullsize Ford F150. Although it had coil spring perches, they were in the wrong location and the axle had radius arm brackets which wouldn't be compatible with my TJ's five link suspension.

I had several options open to me:

1. Cut the brackets off my stock D30 and re-attach them to the D44.
   This wasn't appealing since the factory brackets are kind of flimsy and it would also make it more difficult to sell my stock axle.
2. Manufacture new brackets for the axle.
   This was feasible but would involve an incredible amount of metalwork.
3. Look for an aftermarket solution.
   This option came about when I saw an ad for Rubicon Express' bracket kit for Jeep coil spring suspensions.

What follows is a description of the installation of the brackets, as narrated by Rob (Rye-Guy) Bryce. I was fortunate to have his (and others') assistance in doing this project. Take it away, Rob:

Bracket Installation

Rubicon Express' Front Axle Bracket Kit

It may sound odd that such a kit would not come with instructions, but considering the complexity and what is involved, this is no surprise. If you need lots of instructions and diagrams, then you should consider having a professional shop install the kit on the axle. That said, it can be done by someone at home, with the right tools. This article is laid out for how your average Shade Tree Howler Monkey should work with this kit. Do not consider this article as instructions, but rather "guidelines".

Step 1: Preparation

Yup, you guessed it: strip the housing and torch/grind-off all the stock brackets. Where it's going, it won't be needing them.

Torching off the radius arm bracket.

All old brackets removed, different angle.

Rob grinding the tubes smooth.

Step 2: Measurements and Set-up

It is important to take as many measurements as possible before you even consider removing the axle from the vehicle. What is important is:

• the caster, measured at the ball joints
• the angle from horizontal that the axle coil spring perches sit
• the pinion angle
• the distances between the lower control arm mounts, measured at the control arm bolts
• the distances from the axle tube to the lower control arm bolts, direct, off horizontal, and off vertical (by measuring all three, you can verify your measurements using simple math)

With the control arm bolts removed, measure from the inner side of the bracket to the inner side of the other bracket, at the bolt hole. It gives you an accurate, consistent point to measure from, rather than "guesstimating." Once these measurements are double-checked and written down, the axle can be removed from the vehicle.

It is best to set the old and new axles close to each other. We placed the Ford axle in front of the original Jeep axle. This lets you "eyeball" things quickly and keeps the original axle close at hand to re-verify measurements. Place both axles on stands and adjust them so that the caster on the original axle matches its alignment in the vehicle, and the new axle is set up so its alignment is what you want it set at. With the pinion and caster angles measured, you have a few places against which to verify measurements. We set this Ford axle to 7 degrees caster to match the factory specifications.

If the pinion angle on the new axle is not compatible with the caster, then the donor axle should be fixed before proceeding. Don't be surprised if the caster angle at the ball joints is slightly different. The Ford axle was out by approximately 0.5 degrees from side to side. This can be corrected later when the vehicle receives an alignment.

The center of the new axle should also be located. This Ford axle was easy, it was against the edge of the housing. Had this not been the case, we would have used some masking tape and a pen to mark it. Locating the center of the axle is useful to verify positions for all of the brackets and mounts.

Step 3: Upper Control Arm Brace

Rather than worrying about a good weld to the differential housing for the driver's upper control arm, the kit includes what looks a bit like a truss that fits over the housing. There is then a brace that attaches this to the housing using the upper 3 bolts for the differential cover. Install the cover on the housing, since the brace goes in front of the cover. With this in place, we discovered that the "truss" to which the upper control arm mount is welded was under pressure, so we warmed up one bend and let it cool to let it seat itself correctly. Once this is done, the brace can be welded permanently to the axle. On the driver's side of the truss, though, the weld should not be particularly large, since the coil spring perch will be located very close to the truss.

By the way, the concern with welding to the diff housing arises from the fact that the housing on a Dana axle is made from cast metal. Welding to it as though it were regular mild steel would result in tiny cracks since the cast metal doesn't expand/shrink at the same rate as the mild steel used in the brackets. Furthermore, the abrupt, intense heating and cooling could crystalize the metal around the weld. The proper way to weld to a cast housing to is heat it to around 500 F and then weld it with a nickel rod. That's exactly how we welded the bracket to the Scout D44 used in my Comanche. Trust me when I tell you that using Rubicon Express' truss was much easier.

Diff truss assembled. Note how it bolts over top of the diff cover.	RE bracket modified to fit around the diff cover.	Heating the RE bracket to relieve tension.
Diff breather hole and brake hardline mount hole. These will be obstructed by the control arm bracket so they had to be sealed.	Breather hole bolted, brake hole welded shut.	Welding truss to axle.

The differential breather hole and the brake hardline mount were located right where the "truss" covers the housing (making it inaccessible). This was solved by filling both holes (one with a bolt, the other with weld) and drilling a new breather hole in a different position on the housing. Placement of the breather hole had to be carefully considered to avoid having the ring gear spit the oil out the breather hole while in operation. Unlike the rear axle, the breather has to be on the housing since there is an oil seal separating the housing from the axle tubes.

Step 4: Coil Spring Perches

It's easier to measure the distance between the coil spring perches with the axle removed, so this is an appropriate time. We measured center-to-center and located the new perches onto the Ford axle with similar spacing. We actually relocated these perches out by approximately a half-centimeter to clear the large weld holding the truss to the axle. We chose to do this rather than keeping the coil mounts in exactly the factory location, since I did that on my Comanche axle, and under full compression, the coil will slightly rub against the frame.

We neglected to measure the pitch for the coil mounts on the original axle before it was removed, so we had to measure the frame mount for the coil and verify measurements from my Scout project. These matched at 7 degrees angled back (matching the caster). This angle is important to avoid the coil from "bending" around a slight arc under normal driving conditions. Once distances and angles were re-verified, everything was tacked into place.

Depending on your donor axle, these perches may need a slight modification. No modifications were required for this application.

Angling coil spring perches.	Driver side coil spring perch, close to truss.
Welding passenger side spring perch into place.	Welding driver side spring perch into place.

Step 5: Lower Control Arm Mounts

These mounts are designed to fit tightly against the underside of the coil spring perches. The first important measurement is to space them correctly from each other. Once this spacing is determined, they can be tacked in place to simplify verifying other measurements. You can verify the spacing of the coil spring perches and lower control arm mounts by checking their locations relative to each other. We did this by using the shock mount, which is part of the coil spring perch.

The location of the bolt hole can then be verified against the axle tube on both sides, to match the original axle. We had a bit of trouble removing the control arm bolts from the original TJ axle. We accidentally bent the brackets during this procedure, making measurements more difficult. This is why these measurements should be taken before disassembly.

The horizontal and vertical distances of the lower control arm bolt hole on the new brackets can be adjusted by rotating the bracket around the axle tube. Depending on the direction of the rotation, this may or may not mean slightly modifying the coil spring perches. Rubicon Express, however, has done their homework, and for our application, the ideal location was to keep the lower control arm tight against the coil spring perch. This immensely simplified the task of aligning these brackets.

Depending on your donor axle, these perches may also need a slight modification. This was not the case for this application, but when building my Scout axle, the driver's side lower control arm perch had to be fitted over part of the housing; it would not fit only onto the axle tube.

At this point, we were very satisfied with the alignment with these brackets so the coil sping perches and lower control arm brackets were welded permanently to the axle, and to each other. Constant verification with the original axle helped here, and keeping the axles on stands with correct alignments simplified and sped up measuring. However, it may be prudent to make strong tack welds and return to these brackets to finish welding after the upper control arm mounts are located.

Driver side lower control arm bracket weld. See how close the brackets are to the differential housing.

Welding passenger side lower control arm bracket.

Step 6: Upper Control Arm Mounts

This step is the most difficult to correctly align and place brackets, due to the compound angles and size of the passenger side control arm mount. The first thing we discovered is that the brackets were at different heights. I am unsure why the brackets have been designed as such, but the passenger bracket was about a half-inch lower than the driver's bracket. This affects the geometry, and so the arcs that the axle travels through during articulation.

The other thing we noticed relatively soon is that the vertical distances between the upper and lower brackets is increased from stock. This makes sense, since the Ford D44 housing is considerably larger than the original D30 housing. This measurement also affects the arcs that the mounts, and so the axle, travels through during articulation.

The vertical distances can be corrected by relocating the lower control arm brackets slightly. However, this change can be compensated for by slightly changing the location of the upper control arm mount. A larger concern for us was the difference in height of the brackets. The difference is minor, but the effects on handling and articulation are unknown, so we used 1/4-inch stock to build up the axle tube. And if nothing else, keeping these brackets at the same height makes it far easier to correctly align the axle. We tack-welded it in place, then bent it around the tube using the torch and a hammer. Before doing this, it was important to the locate the position of the passenger bracket.

With the brackets at approximately equal height, we were able to fine-tune the location of the upper control arm mounts. Locating these properly are very important for two reasons in particular: there is no caster adjustment on the lower control arm mounts. This is not a concern for XJ axles, but on ZJ's and TJ's, this removes all caster adjustment. This means that adjustable length control arms are needed to correct the alignment of the axle for this TJ. By locating the upper perches correctly, less adjustment will be needed to correct the caster. the upper control arms are far from parallel with the vehicle, so the "twist" of these brackets is important to avoid unnecessary pre-loading of the upper control arm bushings (or joints).

Aligning upper control arm brackets.	Raising passenger side upper control arm bracket 1/4 inch.	Bending upper control arm bracket spacer to fit housing.
Passenger side upper control arm bracket weld.	Welding passenger side upper control arm bracket bushing sleeve.

It took us more than a few tries to get the brackets properly located. In the end, we located the passenger upper control arm mount vertical, and located the driver's mount to match. By mounting it vertical, we moved the upper mount about 3/16 inch ahead from its stock location, relative to the lower control arm mount to compensate for the extra vertical distance between the mounts. We used small diameter tubing to make sure that they were true with the axle in every plane. Many measurements on both axles were taken before we considered making the locations permanent.

Finally, the "tubes" to hold the rubber bushings can be welded into place on the upper control arm brackets. Rubicon Express supplies new rubber bushings for this, but the "tubes" appear to have extra machining, probably to fit probably a Johnny Joint.

Step 7: Track Bar Mount & Sway Bar Link Brackets

At this stage, locating and welding the track bar and sway bar brackets is relatively trivial. We tacked the sway bracket in place before locating the track bar. The hardest task was drilling a new hole for the track bar mount. It appears that the hole is located for use with an adjustable track bar which we did not have.

Drilling new hole for front trackbar bracket.

Passenger side swaybar bracket weld and trackbar bracket.

Step 8: Steering Stabilizer Bracket

This bracket is not located until we have the axle's steering in place.

Summation

Using these brackets tremendously simplified the task of building a custom front differential for a TJ, XJ, MJ, or ZJ. It took me approximately 3 months of weekends (and some evenings) to design, assemble, and weld brackets in place that took us roughly a day to do here! Granted, the Scout/Comanche project was treading new ground for me in every respect, but if you count your time as money, then you can't afford to build these brackets yourself for the cost of the Rubicon Express brackets. At least, I cannot.

The quality of the brackets is excellent, on par with everything else I've seen from Rubicon Express. The brackets are stamped from 1/4-inch steel plate, so it's strong enough for all but the wildest TJ applications. They may even be sufficient for some full-size applications.

The kit, however, is not for the timid by any means. However, with the right tools and patience, it can be done, and that is what is important. The minor problems we did find are really just that: minor. Considering that these brackets could be used for other applications, this is an excellent generic kit to save time in any coil spring project.