Different Ways to Relocate Rear Axle

[viscacha]

I want to relocate my rear axle 1 ½” rearward and thought the simplest way to do that would be to drill a new hole through the spring packs. The only info I can find about this modification is not to have the existing hole located beyond the clamping force of the u-bolts or else the springs could break in two across the open hole. Has anyone done this to their springs with acceptable results? Are there any other ways to relocate the axle?

I can’t move the spring mounts rearward because the front mount is on the curved surface of the frame so there’s nothing but air beyond its current location. Moving the axle back on the spring would also tilt the pinion downward slightly resulting in less angle needed for a shim I have to use anyway. Right now I need to tilt the pinion down with a 5 degree shim. With the axle positioned back 1 ½” it looks like I only need a 3 degree shim. The amount of shim angle is of no concern anyway but relocating the axle would reduce the shim angle as an extra benefit.

So again, any other ways to relocate the axle on the springs? Thanks. :cool:

[Brad W.]

see if you can turn the springs around... ie, turn it so the current front eye is attached to the shackle and the current rear eye becomes the front. that may get you some length.

to check this out, measure the main leaf from the center of the eye to the center pin (do this for both front and rear eyes). turn the spring so that the longest eye-to-pin measurement is between the front spring hanger and the axle. this **should** scoot it back an inch or two.

I gained ~2" by turning my rear spring packs around (stock '79 wag leaves), but I dont know if that works on J-trucks.

[Sycho15]

Check out Rubicon Express' website. They should have some relocation pads. Basically they sit between the spring and the perch and have new holes in them or something. It might work for ya.

[rockcandy]

I say go for some Tad's perches. They have the relocation holes. I think they allow about 1" fore or aft movement. I have used several sets and have been very pleased with them.

[Tad]

Steve, I'll hook you up if needed.
I used them to move my 14Bolt back 1".
You will also need to drill a new spring pin hole in the ubolt plate as that has to slide back also.
Now, only glitch I see is mine add about 3/4" to 1" of lift.
Do you need a little extra back there?
If not, I could modify the CAD/CAM file, not sure if I can loose that much and still have enough material to weld but I'll be happy to check into it for you.
You could also rotate your pinion at the same time eliminating the shim all together.

[viscacha]

Thanks Tad. I had thought about getting your perches and replacing mine to adjust the angle. Once I drive the truck some that’s what I want to do. I’m still in a set up mode. :cool:

[J.E.E.P]

have any of you tried to drill through a spring pack? as far as I know, they are extremly hard, and brittle, this is why they brake.

[scotty]

yes,you dont want to drill thru all the leaves on 2 spring packs if you dont have to ;)

brad has the best idea,and im pretty sure it will work for ya,ive been told that the wag and j truck have the same rear springs.

[viscacha]

Reversing a J20 rear spring would put the axle rearward 3 ¼”. The hole is way off center. I can drill through a leaf pack very easily but most people wouldn’t have the right tooling so I guess that’s why you don’t hear about more people doing it to reposition the axle. Having an extra hole in the springs is no different than having the hole for the pin. The holes just need to be within the clamping force of the u-bolts so the spring doesn’t flex there. At least that’s how I see it.

I’m beginning to like the idea of adding a shim with a pin on the bottom that fits into the original perch hole and adding an offset hole on top for the springs. Then as Tad mentioned I would add an offset hole on the spring plate. I could weld the shim on the perch for added strength and it wouldn’t be any different than completely replacing the perches. The shim will add .563” to the perch height. I don’t think the extra height will be an issue, but I’ll find out today after I put the front axle back in and get it on all fours. Then I can measure for the exact offset I’m looking at for the rear axle, somewhere around .875” to 1.25”. :cool:

[FSJeeper]

Steve, first of all I would like to compliment you on your project and thank you for sharing it. I am really enjoying watching your progress.

I have heard the exact same thing you have as regards the hole spacing and clamping force. I have seen people move their axles as far as 4" like this with no spring breakage problems, but the idea just does not sit well with me.

If I were you, I would look into the aftermarket replacement spring perches available. They are longer which helps prevent spring wrap, and also have spring pin spacing holes up to 1.5 inches forward and backwards which give you options. The ones I have seen have a pin hole at the stock location, and then 1 forward and one behind that for axle placement options. A lot more work, but you would not have to worry about spring breakage due to the extra hole in the packs.

[viscacha]

Thanks, I’m in the fab mode right now while I have the chance. I’m installing steel shims and I’m almost done. I offset the top hole to relocate the axle. :cool:

[oldyellowwagoneer]

Look for longer springs, anchor the front in the stock location, and make a new mount for the rear shackle if needed. Dennis

[mudslider]

i have a dumb question. why would you want to move your axle rearward? i don't get it.

[eng]

"departure angle"

[Berrett]

Originally posted by eng:
"departure angle"if you are going for departure angle you would probably move it more than an inch, probably something more like fender/tire clearance

[viscacha]

I move it .813” for esthetics. Remember it looks twice as far off as it actually is and I didn’t like the tire not being centered. When I install bigger tires it would look even worse. I made an offset shim to tweak a couple things and it worked out great.

I don’t have a departure angle that I know of. With a 131” wheelbase I just go over stuff with some bumping and banging and then I just continue on. :cool:

http://www.dakotacom.net/~jeepster/100_1758-1.jpg

[eng]

bumping and banging is good in some situations

hehehehee

i wasnt thinking about the only moving back an inch kinda thing always thinkin' hardcore i guess ~my fault