Hey
@devo,
I just finished a 5 hour drive with the 80 and the increased caster without the clanking was great. I do think I heard tie-rod to arm contact on one slow speed bump that I hit while turning pretty hard, but that was the only possible clank so it's very close now, in that department at least
I was at .5ish degree caster before plates, then 5.5ish and now I roughly estimate that I'm around 4 degrees and it drives better than it has since I got the 80
I'm thinking I may try to go with less lift than I was planning to try to end up around 3 degrees per my rough math, when the new springs are in, well that or I'll lift more and go with new arms. I don't see how I could have gotten the full 5 degrees of correction out of these plates given how much I had to grind off the arms and then the plates to stop the clanking.
I've marked the first photo below with the grind points that I used to reduce the caster adjustment. I increased the depth of the lower notch that the front arm bolt passes through and then took the same amount of metal out of the upper caster plate bolt hole. I don't have a photo of the plates / axles unbolted after the adjustment so basically I removed metal where the red dots are in the first photo.
My rough measurement was that the plates originally moved the front arm bolt down about 15mm. The tie rod moves a similar amount to the front bolt though it's not exact. For a number of reasons I went with a 30% caster adjustment reduction and added a 5mm cut to the bottom of the axle mounts. I used calipers to confirm the same spacing on each of the four front/lower bolt holes and I ground slowly with a lot of test fits. The second photo shows how the plates fit on the axle with the 5mm removed. You can see that to take more out will start to require a lot more grinding on the plates as they'll hit the axle tubes.
I was able to make this adjustment without lifting the tires off the ground. First I loosened the rear/chassis-side nut on the arms a little so that the arms could then be unbolted from the axle and dropped down. Just remove/lower one arm at a time and for the arm that you remove it's likely that the axle will push forward a bit, though that could vary. I put a small ratchet strap from frame to axle to allow me to pull the axle back to where it aligned for re-installing the bolts after the grinding was done.
On the inside of the plates, particularly the outer passenger side plate, I had to grind around the inner edge so that the plate didn't hit the welds around the axle/arm mounts. Once you are able to get the plate adjusted for less caster you want to make sure it also sits flush against the side of the axle mount and that it's not high-centered and rocking where it makes contact with a weld.
After you drop the arm down from the axle you can put the plates back on with just the rear bolt. That makes it easy to swing the plate up to help you keep your grinding to a minimum and in line with how the plate will seat. Once the bottom plate notch is where you want it you then open up the top bolt hole until the lower edges of the axle mount and the plate line up. Reinstall the first set of plates with snug bolts that are just loose enough to slide when you remove the other arm, then things will settle into the new position. When both plates are adjusted and the 80s parked back on flat ground you can torque all of the bolts back up.
Paint where you grind to avoid rust and as mentioned above you'll likely want to weld the plates on to some extent once you get them where you want them.
