|I bought the truck new on
February 16, 1989. Since then, I have put on over 307,000km on it. But let's back up
a bit... Within a year of purchasing the truck, I installed a Rugged Trail lift kit. I
left the truck as-is for about 4 years, at which time I moved to the coast. The Rugged
Trail kit had sagged to about 2 inches lift. Tomken had not yet come out with their tall
lift kit, and I was unaware of how to lift it higher. Unable to afford another kit, I made
my own front coil blocks, and had a local spring shop rebuild the rear leaf pack to match.
At a full 4 inches lift, I ran 31's and I was happy for the next couple years.
Over this period of time, I was quite happy with the truck's performance. (Actually, I've always been happy with its performance, just always wanting more!) I had trail rode with Larry Soo for a while now, and I was itching for some more changes. I hooked up with the core of what is now the Island Rock Crawlers, who proceeded to introduce me to trails which were pushing the Comanche's ability. Well, the rest, as they say, is history. What follows is a detailed account of what I consider the most interesting modifications to the truck. But first off, I must thank some individuals for their help, insight, abilities, and encouragement.
|I didn't have many problems
with the original rear Dana 35 axle, except for its appetite for Lockrights! I was running
33's and many people told me "the Dana 35 won't survive" although other than for
Lockrights, it did. My (bad?) habit of overbuilding things insisted that I upgrade,
though. A Dana 44 from a Scout was selected. Jeep runs an odd backspacing, so with
standard offset rims on the Scout axle, the track width remained the same.
It didn't take long to decide that a complete rebuild was in order! The stock gears were 3.54 and I was running 4.10's. The axle had also been neglected by the original owner. Everything was replaced - all the seals, bearings, differential guts, and brake parts. The only parts I re-used were the shafts, the housing, and the brake drums. I wanted to build it for disc brakes, but it was beyond my budget. A few months later, it was ready for install.
The axle received a Lockright. Powertrax was kind enough to replace my last blown Dana 35 Lockright with a Dana 44 Lockright! Plans are to eventually replace the Lockright with a Detroit Softlocker, but this isn't high on the priority list.
Luckily, the Scout uses the same size driveshaft U-joints as my Jeep! That saved the time and expense of tracking down different yokes. I used the stock Comanche emergency brake lines as well - they were compatible with the Scout drum brakes. Install was very straight forward. It bolted in much the same as the stock axle. No gotcha's!
The axle has worked flawlessly since it was installed. I have since had to replace one rear axle shaft, because the splines were becoming twisted. I discovered this when I installed the rear disc brakes (tech article to come).
|The rear suspension has gone
through many incarnations. It has started from stock plus an add-a-leaf, to being rebuilt
to give me ~4 inches of lift, to becoming sprung-over. I've added and since removed
Currently, I have a custom leaf pack which was built for 4 inches lift, with a sprung-over configuration and no blocks. The shocks have been remounted into a configuration that matches Toyota pickups. I am using 13.5" travel Black Diamond XT shocks.
I have also installed a 3/4-'liptical rear suspension design and longer rear shackles to obtain more lift (in place of blocks). This combination yields me about 9 inches rear suspension lift over stock. The emergency brake cables have been replaced with ones intended for a '86 Comanche, because the older Comanche brakes lines were about 4 inches longer.
I'm sure some people don't believe how tall my truck actually is. There seems to be only a few people who are crazy enough to lift these trucks this tall! Well, for confirmation, I decided to park my truck next to my friend's XJ. This XJ has 31" AT's and runs 3" of lift here. Judge for yourself. Remember, the truck now sits about 1-1.5 inches tall than when this picture was taken, too!
|The front axle is definitely
the most involved project I have ever performed on this truck! It is also the one that I'm
most proud of. The front axle started life under a Scout. Since the Scout front axle has a
right hand diff, this meant either swiching to a different transfer case (like a Dana 300)
or moving the pumpkin from the passenger's to the driver's side. I chose the latter
because measurements show the engine/transmission/transfer case combo is offset slightly
to the passenger side. Rather than making new engine mounts, etc., etc, I thought it would
be easier to just move the diff to the passenger side. And at the same time, I could reset
the pinion angle and caster. It was done by a local shop, in such a way that I could
re-use the stock Scout axle shafts.
I considered an old Ford Bronco front Dana 44 but abandoned that option for the following reasons:
By the way, the old Ford Bronco axle width is just about right. Rough measurements show it to be within an inch or so of the Scout axle width.
As with the back axle, the front axle is also assembled with 4.09 gears, and all new seals, bearings, and gear set. Wayne Foster assembled both the front and rear axles. The carrier is a Detroit soft-locker. Yes, it's an automatic locker. But now that I have driven a vehicle with a front locker, I wouldn't dream of putting any other type of differential carrier up there! It's great, amazing, super! I love it!
Control arm mounts on the axle were custom made, and were moved up to give more clearance at the control arms, so I would both hit fewer things, and to improve the control arm angles. I also incorporated additional lift into the coil spring spacers. This first picture shows the new lower control arm tacked in place on the driver's side. Notice how it's not square with the axle tube, to match the angle found on the stock axle. The second picture shows how much the differential housing was rotated from the knuckle yokes, to both improve front driveshaft angles (to cancel out vibrations), and to get the yoke up, out of harm's way. You can also kind of see the inner sleeve installed by the shop when they moved the housing from the passenger side to the driver's side. The last picture shows the passenger side of the axle, with both the lower control arm mount and the shock/coil spring perch in place. I was surprised how much the shock/coil spring perch dwarfed the axle - that's what happens when you build 2.5" lift into it, I guess! The shock holes and the coil spring pad still have to be welded into place.
One upper control arm mount had to be welded to the housing. This is very specialized welding that most welders can't perform. John Edgar performed the surgery at Larry Soo's shop. John Barron used a MIG welder for all the other welding. Yours truly designed the brackets - no brackets were re-used from the stock axle, since the truck remained no the road while this axle was built. All new brackets ranged from 3/16" to 5/16" stock, depending on the purpose of the bracket.
A trick: when you are building a front axle, it doesn't hurt to paint the insides of the axle tubes. To do this, use a spoungy paint roller on an extensions - it works slick!
The axle installed easily,
and the holes lined up better than the stock axle! The picture shows Vern O'Connor lining
up the bolt holes for the upper control arms. The track bar and brake lines are
temporarily swung out of the way, the shocks not yet hooked up. The following 3 pictures
show details of various front axle components. Note, however, that these pictures are big!
I debated making them smaller, but felt it's be worth it in terms of detail to leave them
This axle has proven to be a very successful project. No problems have really turned up, other than its appetite for wheel bearings. I attribute that mostly to a lack of maintenance on my part. If I re-pack the wheel bearings about every 4 months, then I don't seem to have problems. Some people say I should consider changing to an internal hub design, but the Scout axle is unique with than 8-bolt spindle pattern which would make such a conversion rather difficult, and, for me, not worth the effort.
|The front suspension has also
gone through many incarnations. Presently, I run 1 inch spacers on the top of Rubicon
Express ZJ 4.5 inch lift coils, and 2.5" of lift built into the axle, to give a total
of about 8.5 to 9 inches of lift. XJ coils are not tall enough, since MJs (Comanches) are
heavier than the XJs. I am using 12 inch travel Black Diamond XT shocks.
The control arm mounts are moved up about 2 inches on the axle tube. They are also moved back, so that the control arms would continue to clear the axle tube. This had the side-effect of moving the axle forward under the truck, which I wanted to do anyway, to clear 35 inch tires. I'm now running 36" tires without problems. The added side-effect on steering (needing to relocate the steering box to use the appropriate pitman arm) is discussed below.
The control arms are very similar to Tomken's but instead of using poly bushings, I use stock rubber bushings. The result is an extremely quiet ride and lots of flex without any load put on axle or frame components. I do, however, get a bit more front axle wrap than I did with the stock axle. I feel that this is a combination of relocating the control arm mounts on the axle, and of the soft rubber bushings.
If you are building a front Dana 44 for your Cherokee or Comanche, do not relocate the arm mounts on the axle any more than I have. I spent a lot of time drawing pictures of how the arms would look at different points in the suspension travel, and this is as far as I think you can go. And I wouldn't move the mounts this far if I wasn't running so much lift.
At full droop, the coil spring becomes completely unloaded! In fact, when I was using Explorer Pro Comp coils, you can actually remove them! Personally, I see no point in worrying about this, nor am I concerned with the arguement that "no weight on the tire means no traction.", for a few reasons:
At full compression, the coil is asked to do strange things, as is shown in the picture! This, though, will happen on any XJ or MJ set up for lots of articulation. Note, however, how this suspension has been designed that as the suspension reaches full compression (it's not there yet in this picture!), that the tire ends up relatively centered in the wheel-well. This means that at normal ride height, the tire is actually set back in the wheel-well a bit. A side effect is that the coil may rub against the frame rail, making a terrible noise. Unfortunately, I don't think that there is any real cure.
|With ~8.5" front lift,
the steering and track bar took a lot of thinking! As the above pictures and descriptions
show, I went to Chevy steering, and remounted the steering and track bar to avoid bump
steer, etc. Without playing with the coil spring perch, I'm not sure how you'd be able to
move the track bar mount up higher on the stock, though. If you ran a shorter track
bar, you could. But you want as long a track bar as possible. Or at least keep the
track bar length and the drag link length as close as possible.
I wanted to flip the steering parts as well, and use as many over-the-counter parts as I could to make replacing parts easier in the future. Second priority was to keep the "family" of parts all the same. In the end, I used strictly Chevy parts (cheaper and very heavy duty), but had to make my own tie rod and drag link (from Chevy parts, just it meant I had to weld up steering parts, which I'm not keen on, but it seems to have worked, and it's definitely lots stronger than the stock tie rod parts.) I also had to reverse the taper on one tie rod end - where the steering stabilizer would normally mount.
My setup works great! There's a few things that you have to keep in mind, though:
The decision to flip the steering on top of the knuckles was mandatory for me. The decision to drop the inverted Y was arbitrary, but a good one in my opinion. The effects on the vehicle's toe-in increases as the inverted Y angles change. And since I 'wheel a lot I figured I might as well drop the inverted Y to keep my toe in the same regardless of what I'm asking the suspension to do.
If you look closely at the above picture, you'll notice that I've already managed to put a slight bend in the tie rod, near the right tie rod end. *laugh* It's a good thing I flipped them on top of the knuckles - it would have bent up the stock steering like a pretzel for sure! I dropped the front end onto a stump from a few inches. It likely affected my toe in by about a half a millimeter - not enough to worry about!
Also, Dana 44 knuckles are longer than the stock D30 ones. This means that since I'm still running the stock pitman arm, my steering doesn't turn as sharp as it should. I've looked at getting a longer pitman arm, but that means relocating the steering box on the frame, which really isn't an option. I can't use shorter knuckles or the steering will interfere with the coil and track bar mounts. So right now I'm stuck with a poor turning radius. The flip side to this, is I have less chance of breaking a front U-joint due to extreme angles.
It is also possible to break these parts. Well, I haven't broken the Chevy steering parts yet, but have the track bar a few times. I used to always blow out the factory tie rod end on the track bars, so (as the picture shows), so I replaced the end with a 3/4-inch heim joint. Since that, I have broken the track bar once (shown, that's now my spare), and 5 heim joints. I've broken most of the heim joints within the past year - since I've gone to the 36" Swampers. Too much weight and traction, I guess. The quick fix worked once, but one break left me stranded on a mountain from 4am 'til 8am...good thing we had cell coverage! Lesson learned: you can't have too many spare parts!
|Well, I wanted to make the
truck more self-sufficient. I hate things to go wrong, especially out on the
trail. And dual batteries also help for winching, so I talked to a few friends
(credit goes to Vern O'Connor) and came out with a nice, cheap, simple way of hooking up
two batteries. Here's the details.
I took the opportunity to relocate my main battery at the same time in preparation for the on-board air project. SInce my relocation doesn't apply to XJ's, I won't mention it here.
was a fun project. And it has been a very practical project, too. Sure, I use
the heavy duty axles and the long travel suspension every time I go off-road, but I've
used the on-board air just about everywhere.
I originally sourced a few York compressors since I didn't want to deal with oilers and separators and because it has a higher flow rating than the stock compressors. Take my advice: on a XJ or MJ, it will take a _lot_ of work to fit a York under the hood. Yorks work under YJ hoods, but for an XJ or MJ, choose the factory compressor. It's easier to install on the vehicle and you don't have to worry about finding a serpentine pulley for a York (tough but possible).
If you notice in the picture, the battery is missing! My dual batteries project relocated the primary battery, leaving me with room for:
Since these pictures, the underhood assembly has been slightly relocated to make room for the larger welder alternator. The shocks have also been relocated since the picture showing the tanks was taken.
Here's a few extra pointers for anyone building/using their own on-board air system:
here is an easy project that is under $10! I stole this idea from some buddies with
Jeep YJs. I was always worried about the engine sucking water if I get into
something really deep. The factory air intake may be good in the sense that it pulls
in cold air, but I really wanted it higher. And I didn't want to pay an exorbinate
amount of money for something outside the body that is waiting to get ripped off in our
The solution: some simple PVC pipe and a few elbows. A hole is cut into the bottom side of the air box, and the original intake is blocked off with a piece of flat plastic. The air intake has moved up some 5 inches and the water has to change direction in order to enter the air box. And it's tidy. It won't give me 100% protection, but in theory the ignition should die from being submerged in water before the engine can hydro itself.