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Another YJ unlimited build

This is what's next. Diamond 9" housing, 5.43s, ARB, 35 spline, 05+ super duty unit bearings.

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Just read thought the whole thread! Looks sweet dude good work. Are you going to keep the torque arm with the new axles or go to a 4 link?
 
Right_side_up said:
Just read thought the whole thread! Looks sweet dude good work. Are you going to keep the torque arm with the new axles or go to a 4 link?
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I'm sticking with the torque arm. It works so well off road and on. I drive this thing on 1000 miles trips with the trailer behind it and run some pretty hard trails and it just flat out works. Looking forward to getting the coils up front with the new axles. I don't think the leaves are hurting me drastically, but I think there are absolutely gains to be found with coils.

I put the new 3rd in the housing and slipped the cups and unit bearing on the housing. Probably just for the pics, but did some measuring too. This axle should end up 68" wide if my plan comes together.

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I have an alignment tool.. The housing is a bit off so I'll probably try to straighten it out and trim the ends to length in the next week or so.
 
Cool build.

I'm surprised your crossmember for the forward torque arm mount isn't deflecting. It didn't appear "enough" for that application.
 
JohnnyJ said:
Who did you get the cups from?
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The guy I bought the housing from made them. Laser cut and then he machined them I think. Im4yotas ???

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The Freeak said:
Cool build.

I'm surprised your crossmember for the forward torque arm mount isn't deflecting. It didn't appear "enough" for that application.
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I think the lever arm that the torque arm is so long that the forces imparted on the crossmember aren't that high. I can't remember off the top of my head, but I think the end of the torque arm is around 40" from the centerline of the axle, so 25% of the force the brackets may see in a triangulated 4 link. That strut that runs forward and ties to the transmission crossmember removes most of the twisting moment from it, so it is mostly seeing a lifting force.

When I originally did the stretch, I had a 4.6L stroker. It wasn't an LS, but it had more balls than a stock 4.0L. I was on 35s with 4.88s. When I installed the 37s, I was having engine issues so I installed a mostly stock 4.0. The stock engine with 4.88s and 37s is pretty anemic. This round of mods will include 5.43s in the rear end. I don't think that crossmember will be a problem, but if it is I'm sure I can deal with it.
 
Yea coils on the front will be way different. My Tj can get through washboard and just rough roads way faster than my brothers Yj. I think you will probably get more flex as well.
 
badass build!!! The body work is cool.

Explain the rear suspension? I take it that its common in the car world but I have never seen that before.
 
06h3 said:
badass build!!! The body work is cool.

Explain the rear suspension? I take it that its common in the car world but I have never seen that before.
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It's a torque arm suspension. The torque arm is only for controlling axle wrap. It keeps the pinion pointed at the t-case and that's it. The 2 control arms located the axle for and aft. Mine are bent simply for clearance. There is also a standard panhard or track bar to locate the axle laterally.

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I used control arms from an LJ kit made by Nth Degree. Jim Frens is the guy who designed it. He was a suspension engineer for Jeep for a while and is fascinating to talk to. I just really liked his kit, and found a kit someone was removing to go full buggy on the old board. I have the subframe and front arms as well. I don't think I'll be using the subframe, but I'll probably use the arms for the front coil conversion that I'll be installing as soon as the rear axle is done.
 
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I worked up the nerve to dial in my measuring today. I set up the unit bearings and cups on the alignment bar, measured out the WMS I wanted, and then measured where that put the cups.

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I translated all of that over to the housing and clamped it in the bandsaw.

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I cleaned up the ends and then spent an hour on the lathe making pucks for my alignment bar. I didn't have any stock to make the pucks 1 piece, so I made 2 pieces to bridge the gap from the 1.250" alignment bar to the 2.625" ID of the tube.

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The pax side is ~3/32 off, so needs to move 3/64" to be dialed in.
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The drivers side is a hair over 1/8 off.

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I've seen a ton of videos of straightening an axle with a torch and quenching, but I don't think any of them were on axle tubes this thick. I can't imagine it wouldn't work, I just wonder if it will be as effective.
 
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Have you punched the numbers into link calculator? I know torque arms work great on the street and road courses. But those don't have a lot of suspension travel.

With no link/pivot point where the torque arm connects to the axle housing (it being a solid connection) I'd be very interested in how things want to move with more than just a few inches of travel. You don't want to run out of the movement that the front of the torque arm has.

I'd punch in the numbers just to be sure it doesn't try to make the upper links longer or shorter when the chassis mount runs out of movement. Since that can't happen, it becomes bind.
 
gt1guy said:
Have you punched the numbers into link calculator? I know torque arms work great on the street and road courses. But those don't have a lot of suspension travel.

With no link/pivot point where the torque arm connects to the axle housing (it being a solid connection) I'd be very interested in how things want to move with more than just a few inches of travel. You don't want to run out of the movement that the front of the torque arm has.

I'd punch in the numbers just to be sure it doesn't try to make the upper links longer or shorter when the chassis mount runs out of movement. Since that can't happen, it becomes bind.
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I ran the numbers back when I built it to see how it compared. I don't remember the specific numbers, but I do remember it being in line with most of what I read on other builds online.

Here is a pic of the front end of the torque arm. It's a rod end on top of a shackle with a bushing. It will not be the limiting factor in vertical travel. I can use all 16" of shock travel, (maybe 14", can't remember), at any rate, no limit to the usable travel from the torque arm.

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Full droop, or close to it. The track bar probably limits more than anything.

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Somewhere close to stuffed.

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My sway bar is probably a little stiff for max flex. I rarely hit the rear bump stops under flex, only when both sides stuff. That is what limits my travel more than anything.
 
YJLOPES said:
I ran the numbers back when I built it to see how it compared. I don't remember the specific numbers, but I do remember it being in line with most of what I read on other builds online.

Here is a pic of the front end of the torque arm. It's a rod end on top of a shackle with a bushing. It will not be the limiting factor in vertical travel. I can use all 16" of shock travel, (maybe 14", can't remember), at any rate, no limit to the usable travel from the torque arm.

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Full droop, or close to it. The track bar probably limits more than anything.

1702443993845.jpeg


Somewhere close to stuffed.

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My sway bar is probably a little stiff for max flex. I rarely hit the rear bump stops under flex, only when both sides stuff. That is what limits my travel more than anything.
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Thinking about how that works is kind of like thinking about what makes you alive...

I noodle through it for a bit, get the piss shivers, then stop thinking about it and just accept that it works. :flipoff2:

Mainly just on loading, but I assume the shackle makes it so there's almost zero tension since it just rotates.
 
YJLOPES said:
I ran the numbers back when I built it to see how it compared. I don't remember the specific numbers, but I do remember it being in line with most of what I read on other builds online.

Here is a pic of the front end of the torque arm. It's a rod end on top of a shackle with a bushing. It will not be the limiting factor in vertical travel. I can use all 16" of shock travel, (maybe 14", can't remember), at any rate, no limit to the usable travel from the torque arm.

1702444997478.jpeg


1702443824231.jpeg


Full droop, or close to it. The track bar probably limits more than anything.

1702443993845.jpeg


Somewhere close to stuffed.

1702445070824.jpeg


My sway bar is probably a little stiff for max flex. I rarely hit the rear bump stops under flex, only when both sides stuff. That is what limits my travel more than anything.
Click to expand...

Yep, that'll work. Well done.:beer:
 


Stupid side project that has nothing to do with anything super tech heavy. My daughter said riding in the jeep was cool, except it was loud. My buddy stopped by with his son, so I put him to work installing some Killmat. It's so cool seeing kids doing something that isn't on a screen.
 
Starting to dial in the width. Hopefully tack the cups on in the next few days and start on getting the torque arm mount in place. Not sure how the fat man in the red suit will impact that just yet. Once those items are checked off, I can slide it under the jeep to get the rest of the brackets in place.

I'm pretty stoked about this axle.

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YJLOPES said:
It has been a slow couple of days sorting how things will fit. I had stretched the wheelbase previously around 3-3.5" on both ends using Rancho 44044 springs which are Waggy fronts. They have similar dimensions to YJ springs, but with a 2" offset center pin and offer around 4-4.5" of lift. I also used offset perches to get the other 1-1.5". When I added the 15" of this stretch, I thought I'd just add it to the stretch that was already there which when I measure put me around 114.25" wheelbase. Packaging concerns mostly centered around the coil spring perch relationship required my to rethink that and give up about 1 11/16". I was scratching my head trying to keep the axle back and it occurred to me, Why? I was after every last inch before, but now I'm covered up in wheelbase, no need to get greedy if if makes life so much easier to go this way. I finally settled on a rear axle location that allowed me to sort out the coil spring perch issue and makes the track bar fit well, so I welded in the upper spring perches and tacked the truss on the axle for fitting everything else.
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So what Wheel base length did you end up going with? I've been messing around with the 4-link calculator quite a bit lately and I think I have settled on some numbers. Did you mess around with Anti-Squat, or any of that? Sorry if you mentioned it somewhere else in your build thread.
 
67StingrayJ said:
So what Wheel base length did you end up going with? I've been messing around with the 4-link calculator quite a bit lately and I think I have settled on some numbers. Did you mess around with Anti-Squat, or any of that? Sorry if you mentioned it somewhere else in your build thread.
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112"

I built this using what I thought was a pretty well thought out kit. I made some minor tweaks to fit my needs. I ran all of the numbers as close as I could determine in the original kit and with the mods I made and the difference was pretty minor. I honestly don't remember any numbers, I just know it flat out works. It is so much better than my old SUA leaf springs and I have no complaints about the way it works. Maybe one day I'll get bored and check all of the numbers for reference.
 
Trying to sort the rear brakes before I put the axle in. Here's the plan I've come up with.

05+ unit bearing
99-04 Front Rotor
2015 rear calipers
Bracket I make to connect it all



I've ordered some 2015ish Tesla electric parking brake calipers to try to fit in the mix as well. We'll see if that comes together like I think it might.

I tried to add some pics but apparently .HEIC files aren't okay anymore???
 
First problem.....

The 2015 F250 rear pads are just a hair bigger than the available braking area on the 99-04 rotor. I think you could make it work, but I'm this deep in to it so I figured I'd try some options.
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I have a set of 05-08 F250 rotors for my front axle. They seem to fit much better with just a bit of rotor braking surface showing inside and outside of the pad.

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What are the concerns about the pad having a biggersurface area then the rotor? Wont it just cause a small amount of pad that never gets worn and nothing else major?
 
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