In March, we moved to the front. Because the Dodge axle has a cast in perch on the axle, the spring to caster & pinion angle was set. Well, unfortunately, the geometry of the spring mounts in the Jeep was vastly different from the Dodge, and we determined that the spring would need to be "s" shaped. We went to a custom spring shop to make sure we weren't crazy, and they agreed with us that it wasn't really doable with a normal spring. They might be able to make one, but at the cost they quoted, suddenly a multilink front end became comparable. So, out went the leafs, and in went much thinking. I did lots of research about 3/4/5 link systems. I decided I liked the 5 link best. There are four locating arms that run longitudinally with the truck, and one transverse pan hard bar. The two links on each side are close to each-other when looking down on them. This let me have decent geometry without a massive lift. Normally, on a three link, guys will run the single top arm to the trans crossmember. This would not work with so little lift. Plus, one top arm sounds scary. (I don't think I even have four inches. Hard to tell though with how sagged the front end was originally. The front end rides about even with what the original rear height was.) This five link setup is stock on newer 2500 Rams, and I believe also on TJs/JKs.
Here is a picture of the truck after we pulled the stock axle out:
I considered selling a kit to make FSJs levitate. It looked pretty cool. But then I decided that wheels are probably the way to go for the police and all. So I mocked up the links in PVC first:
I chose to use 2" OD X 0.25 Wall DOM tube for all four arms, and 1.50" OD x .25 Wall DOM for the pan hard bar. All Heim joints are from RuffStuff, as is the DOM (yes it was much cheaper there + shipping than my local steel yards.) and the frame mount for the top link. The Heims are 7/8X7/8. The top link on the frame end has spacers to reduce it to 5/8, and all the other bolts are 3/4. The axle mount and lower frame mount are from Ballistic Fabrication.
The springs/shocks are 12" travel Fox Factory 2.0 Emulsion coilovers with 12" 350lb/in and 14" 450lb/in springs. In order to get a relatively long coilover in with very little lift, I needed a very large shock tower. I needed about 25" from eye to eye on the coilover to be between 50/50 & 60/40 Droop/Bump travel. Few (one) companies made the 18" tall tower to accomplish that, and none of them fit in the wheel well. I mocked up a tower in cardboard that would do the job:
Then I drew up the tower on the computer and sent it over to Ben, a friend and the owner of Focused Light in Arvada Co. He's a great guy with an awesome metal fabrication company. They cut the towers for me out of 1/4" steel, and then sent them out to be bent. In two and a half weeks, they were back in steel.
The Panhard bar was another interesting challenge. The steering on these rigs, as I'm sure all of you know is transferred with a drag link laterally. To minimize bump steer, the Panhard bar needs to be at the same angle and be the same length as the drag link. The problem rose again from the cast in perch. It added lots of width to the differential housing casting, eliminating the extra room where a Panhard mount would normally be welded to the axle. I decided to use the cast in perch AS the panhard mount. I got a 1"x2.5"x18" (2.5" wide is stock Dodge spring width) bar of steel, cut it to 7.5" in length, and had an 11/16" hole drilled down into it. Then I threaded the hole to accept a 3/4x16 TPI bolt.
Like so:
Then, I bolted that piece of steel in place of the old leaf spring:
I need to grab a shorter bolt, and add a bolt where the bolt that holds the spring pack together would be, but other than that, I think it should work.
I also made mounts for the axle side of the coilover. They can be seen clearly two pictures ago.
I had trouble with porosity I couldn't solve while welding the lower frame mounts. Then I noticed the factory Jeep weld was essentially hollow. Crazy porous. So I ground it down. This was about the last 1/4 of the factory weld:
Built on Friday afternoon?
Anyway, after I ground all of the factory weld out, I had no more problems welding.
Lining up the shock tower with the shadow of a plumb bob:
Link Axle Mount:
Top Frame Link Mount (It needs a shorter bolt)
Another Picture
Panhard Frame Mount Tacked In
Passenger Side Axle
Lower Frame Mount Welded
It's late. I'm going to bed. I'll post more in the morning.