Chuzie's monster transformation

[chuzie]

Day 5 (1 Sep 10)
Objectives for today:
1. Clean, prep, and paint rear axle for 4-link.
2. Prep frame for 4-link
3. Prep 4-link parts for fitting and welding
4. Install cross-member, links, and frame mounts

Today was a very productive day, which is a relief consider the past few have been really tough.

I started out by plugging the brake lines and capping the vent line. Then I pressure washed the rear axle housing. Found some red paint under all the layers of gunk. Can't really imagine why the previous owner would have a red axle.



Once the axle was nice and clean I broke out the plasma cutter and removed the spring perches, bump stop mounts, and shock tabs. I didn't want to risk damaging the axle housing so I decided to sacrifice the mounts and then grind down the remains with an angle grinder.




Next, I started to fit the cross member or truss to the axle housing. The first thing I did was center it horizontally and mark the outline of the truss on the housing for reference. Next was the grinding and is where a lot of trial and error and patience came in to play.

The first time I placed the truss on the housing the outer ends where the truss mates to the tube were not sitting flush. The truss was basically tettering on the high points on the top of the housing. At first, I tried marking the points I thought were causing the issue with a sharpie; thinking a few passes with the grinder would fix the issue but the progress was slow and painful.



After about 10 rounds of grinding and very little progress, I decided to start using an extra can of primer to highlight the problem areas in need of grinding. I painted the housing and placed the truss on top while the paint was still wet. The paint transferred to the truss at the high spots I needed to grind. After about, I kid you not, 40 passes. I finally got the truss to fit the axle like a glove.

I then painted the axle with my cheapo black paint and then cleaned up the areas necessary for welding. Objective 1 complete.



The stock spring hangars, bump stop mounts, and shock towers had to be removed from the frame to accommodate the 4-link. I started to use the plasma cutter but decided to stick with the angle grinder for the sake of my frame. It took hours to just get the forward spring hangars and bump stop mounts removed. By then I was so beat I just left the rear spring hangars and shock towers for another time since they will not directly affect the installation of the 4-link system. Objective 2 incomplete due to remaining mounts.



The truss and the frame mounts had to be prepped for welding. We ground down the powder coating to about 1/4 on all the surface affected edges.



Next I assembled the links by mating the heims and lock nuts. As always, I coated everything with anti-seize first. I ran into one issue when installing the heims. One of the 3/4" heims for an upper link did not want to thread more than half-way so we had to run a tap through the link and clean out the threads. It was not a powder coating issue either. Actually, a decent amount of metal material was removed. Not sure what happened with that one but it worked like a champ after we re-tapped it. All the heims were bottomed out and then run back out 4 full turns to allow for adjustment once installed on the Bronco. Objective 3 complete.







Now for the part where we actually start to get some cool stuff done. First, Chuck tack welded the truss to the axle. Then we slid it under the Bronco and installed the tires.





At that point we needed to position Bronco for correct ride height, position the axle for the correct wheel base, center it laterally, and set our pinion angle. We set the ride height almost equal to where the front was sitting. It may be about 1/2" higher. We used two jack stands on the rear of the fram to secure the Bronco.

Since we did not take and measurements or mark any reference points prior to removing the axle, we had to start from scratch in terms of laterally centering the axle. Here is how we did it...

We marked the center of the forward and rear frame cross members. Then, we took our handy laser level and shot a beam connecting the two points. The beam was superimposed on the axle and truss and we used that to center the axle perfectly under the Bronco.

Next we measured the wheel base. Stock is 92". We had read some folks were sliding theirs back about 2" so we decided to give 94" a try. To obtain our wheelbase measurements, we took the laser level and marked the center of the front hubs on the floor with tape. Then we measured back 94" and marked that with tape too. Then, we used the laser level to shoot another line where the center of the rear hubs should be positioned. We had to measure it about 3 times to get it right since each time we moved one tire the other would move slightly.





Next, we had to setup our pinion angle. We decided to use 0 degrees (relative) considering we will not have any wrap issue. Once we got the pinion angle set we used the jack to hold it in place. We double checked the aft clearance and determined that 94" was too far back as the truss would contact the rear frame cross member if it compressed too much. 93" was the compromise we went with. We can still fine tune the system later if we desire to get closer to the rear.

Once everything was measure and set we started to install the links to the truss and frame mounts in preparation to weld the frame mounts to the frame.



The frame mounts need to be reamed to accept the link bolts but that was not big deal. This stuff is pretty heavy though!

Once everything was connected we marked the frame locations and called it a night since it was getting late. Objective 4 incomplete.



Day 5 complete.
Objective 3 incomplete
Man Hours worked: 10
Total Project Man Hours: 49