Ace

At one point it started to become doubtful if this was in fact a project I could actually do. Initially, the need for these seemed doubtful. But by the time I had the old Cummins making some respectable power I started to notice a little more driveline chatter if I wasn't careful pulling out, especially in reverse. I suspect increased torque was causing a little axle wrap. I started thinking about this when I learned just how weak the Skyjacker springs were soon after I got the truck. So I decided to come up with a different design, guaranteed to positively control axle housing torsion without binding the springs, allowing them to work throughout the full range of suspension travel. At the time, the Skyjackers seemed deficient only in load carrying capacity, not torque-handling capacity. But after a year or so of power mods I was noticing more of a tendency to generate some driveline shudder or clutch grabbiness. That problem is now completely solved. here's what fixed it:

http://stuff.is-a-geek.net/PhotoAlbu...cs/CTD_144.jpg

Various vendor and homebuilt solutions all seemed questionable to me. Some of the newer things like Rize sells may work pretty well in the forward direction, some simpler designs can operate only in a very limited suspension range without binding, and yet others appear to be little more than bolt-on weight-adding suspension binders. They are not ladder bars, Caltracs, or any of the traditional type things you see being called "traction bars." I have not seen anything remotely similar, but the things I'm unaware of would fill volumes. I'd appreciate it if anyone has seen something like this before, let me know the source in case I'm infringing somebody's design, claiming it as mine, though in all honesty, I did dream it up myself. I'm calling them "Torque Links."

http://stuff.is-a-geek.net/PhotoAlbu...cs/CTD_142.jpg

The bars bolt solidly to the axle u-bolts in back and track the front frame mount on a sliding pivot link. The portion of the link that connects to the bar itself is basically a six inch long 5/8 bolt with a big honkin' head formed into the slider collar.

http://stuff.is-a-geek.net/PhotoAlbu...cs/CTD_138.jpg

This is the pivot that allows for uneven spring flex when going around corners or off road. The “lever” or axle mount that resists tourque-induced axle wrap, extends down 8 inches below the axle centerline, with a four foot long extremely rigid “handle” (the actual bar, itself) tying it to the front link. The link assembly freely pivots and moves up/down with spring compression/extension but cannot move in any other direction. I had one heckuva time getting this to work properly, but persistence finally payed off, and I was able to engineer a super-strong sliding link that properly tracks suspension travel while torsionally locking the rear axle housing at the same time.

Before getting down to business, I tested my theory by mocking up a full-scale model with pieces of wood and hanging it under a shelf against the wall with some string through the u-bolt holes. Holding the other end and pivoting to simulate axle twist confirmed that it travels in a forward/up or rear/down arc. The link end is already a half inch forward before the axle twists even one degree. But with the link installed it cannot move forward or backward, only up/down along the slider rail, tracking the leaf spring's path, which I tested on the truck like this:

http://stuff.is-a-geek.net/PhotoAlbu...cs/CTD_134.jpg
http://stuff.is-a-geek.net/PhotoAlbu...cs/CTD_136.jpg

That was the hard part - getting the rails bent just so and angled to track without binding. I hammered a 2nd smaller section down into the rails making them double thick for extra strength. I was able to bend them by heating them up red hot with a cutting torch. Then took it back and forth for mock up umpteen times until I got it right - somewhat tedious.

http://stuff.is-a-geek.net/PhotoAlbu...cs/CTD_137.jpg

A side view of the axle movement through compression and extension of the springs (at least on my truck) looks kinda like a warped upside down “J” with most the top cut off. It moves in close to a straight line (although not perfectly straight) up and back through the bottom half of the travel. That's why you can get away with just bolting in a bar with a couple heim joints. But I'd hate to see what that's doing to the frame and axle mounts with a heavy load on if it's not blocked. Cutting out the u-bolt mounting plate to fit the contour of the shock plate was not too difficult, just time consuming.

http://stuff.is-a-geek.net/PhotoAlbu...cs/CTD_127.jpg
http://stuff.is-a-geek.net/PhotoAlbu...cs/CTD_129.jpg

A cool feature I added is greaseable copper bearings on the slider rails to keep the clearance tight as possible and hopefully make it last:

http://stuff.is-a-geek.net/PhotoAlbu...cs/CTD_141.jpg

I'd hoped they'd be pretty much a bolt-on install, but that ended up being far from the case. I doubt it would be practical to mass produce these because of the customization necessary to get them to operate without binding. Probably about half the time spent on these was mocking up and checking travel, taking down for a small adjustment and doing it all over again many times. I even ended up adding a shim (washer) on the passenger side pivot because somehow something (?) shifted enough during final assembly to require opening it up another 1/16in. Those clearances, the slider rail angle and bend radius would be all slightly different depending on lift, leaf spring condition and other details. Six nuts for the driver's side frame mounts had to be blinded in behind the fuel tank (welded). I wasn't going to risk having to pull the fuel tank again just to tighten a few bolts that eventually worked loose. The e-brake cable also had to be lowered a wee bit to clear the lower frame mount on that side as well. Just another couple hours spent fabbing up a custom part, no biggie.

http://stuff.is-a-geek.net/PhotoAlbu...cs/CTD_145.jpg

Apart from the axle u-bolts, the basic hardware holding them together is three 5/8" bolts. One is the previously mentioned pivot, with another one holding each end of the slider rail. I'm pretty sure they're strong enough to handle the job, but I decided to test that to some degree by driving around with only one side installed for a week and doing some fairly hard pullouts along the way. Not max power launches mind you, but enough to see if anything was going to break. I'll leave the max power launches to you guys who actually seem to enjoy breaking stuff! Sure enough, the driveline shudder I had been experiencing was completely eliminated, even with just one link installed. The bars add about 20 pounds of unsprung weight to each end of the axle. Small price to pay for the beneficial effect they'll have on u-joint/pinion longevity, not to mention easy trailer backing and overall smoother driving experience. Here's the rest of the pics from the build process I haven't described in detail above:

http://stuff.is-a-geek.net/PhotoAlbu...cs/CTD_128.jpg
http://stuff.is-a-geek.net/PhotoAlbu...cs/CTD_130.jpg
http://stuff.is-a-geek.net/PhotoAlbu...cs/CTD_131.jpg
http://stuff.is-a-geek.net/PhotoAlbu...cs/CTD_132.jpg
http://stuff.is-a-geek.net/PhotoAlbu...cs/CTD_133.jpg
http://stuff.is-a-geek.net/PhotoAlbu...cs/CTD_135.jpg
http://stuff.is-a-geek.net/PhotoAlbu...cs/CTD_139.jpg
http://stuff.is-a-geek.net/PhotoAlbu...cs/CTD_140.jpg
http://stuff.is-a-geek.net/PhotoAlbu...cs/CTD_143.jpg
http://stuff.is-a-geek.net/PhotoAlbu...cs/CTD_146.jpg
http://stuff.is-a-geek.net/PhotoAlbu...cs/CTD_147.jpg
http://stuff.is-a-geek.net/PhotoAlbu...cs/CTD_148.jpg
http://stuff.is-a-geek.net/PhotoAlbu...cs/CTD_149.jpg
http://stuff.is-a-geek.net/PhotoAlbu...cs/CTD_150.jpg
http://stuff.is-a-geek.net/PhotoAlbu...cs/CTD_169.jpg
http://stuff.is-a-geek.net/PhotoAlbu...cs/CTD_198.jpg

wannadiesel

Wow! Looks like more than a couple hours!