Actually, after thinking about it, there's only so much I can do about the steering ratio. In order to make the knuckles move less, either the distance between the ball joint and the drag link needs to be longer, or the pitman arm needs to be shorter. When I make my high steer arm, I'll just keep the distance as far as I can within the packaging constraints, but if that doesn't work out, I'll make a custom smaller pitman arm.
Doing It The Hard Way - JL Steering Box and a Front Stretch
- Thread starter carrotman
- Start date
B00mb00m
The Church of Cutting Brakes of Atlas-Front Digs
Supporting Member
Ride of the Month Winner
those of following Blaine's footsteps here run 3/4" bolt. That's all i can say, obviously stock got away with smaller. If you run double shear smaller will do better.
If you're welding to the knuckle, i'd add on a spot for mounting the hydraulic ram to the knuckle so you don't have to clamp on the tie rod.
Thanks! I'll stick with that to be safe then. Come to think of it, the Currie track bar JJ is single shear at the frame end, and I think the bolt is about 3/4" there too.
Good point on the steering ram!
Good point on the steering ram!
I just checked that Currie track bar bolt size, and it is actually 5/8". The JJ ball for that joint has a bore size of .625" and an OD of .8" at the thinnest spot. Boring that hole out to .75" definitely won't work because it will leave a wall thickness of .025" on the centering ball. That being said, if the factory bolt is 5/8" and single shear, and they deemed that safe enough for production. I've also never seen someone reporting a failure on it.
A 5/8"-18 bolt has a tensile stress area of 0.256in^2. Assuming a grade 8 bolt has a tensile strength of 150,000psi, that gives the bolt a tensile strength of 38400lbs. Shear strength is 60% of that, so 23040lbs. Take that with a grain of salt because all those numbers are from random online charts and I'm not good at math. 23000lbs seems like a lot of lateral force for an axle, so I think this should be ok.
The reason I want to go with a JJ instead of a standard rod end is I just want something greasable with a long service life. Florida humidity seems to wreck any bare steel surface pretty quick and I don't want squeaks and creaks if I can avoid it.
Edit: did the calculation for a 9/16 bolt too, and the shear strength should still be 18270lbs. Still probably plenty, but I'll stick with 5/8" to be safe. The bolt will probably start bending far before the shear limit, so plenty of margin is a good thing.
A 5/8"-18 bolt has a tensile stress area of 0.256in^2. Assuming a grade 8 bolt has a tensile strength of 150,000psi, that gives the bolt a tensile strength of 38400lbs. Shear strength is 60% of that, so 23040lbs. Take that with a grain of salt because all those numbers are from random online charts and I'm not good at math. 23000lbs seems like a lot of lateral force for an axle, so I think this should be ok.
The reason I want to go with a JJ instead of a standard rod end is I just want something greasable with a long service life. Florida humidity seems to wreck any bare steel surface pretty quick and I don't want squeaks and creaks if I can avoid it.
Edit: did the calculation for a 9/16 bolt too, and the shear strength should still be 18270lbs. Still probably plenty, but I'll stick with 5/8" to be safe. The bolt will probably start bending far before the shear limit, so plenty of margin is a good thing.
Last edited:
Chopped off my JK spring seats and tacked on my backwards TJ ones. Everything seems to line up way better now. Picture is at full droop. I think the trick to keeping the jounce bucket off the front of the spring is to make sure the back of the spring seat is a few degrees higher than the front. It bows the spring slightly which gives it the clearance it needs.
I was planning on just using hockey pucks for the lower bump stop, but I'm thinking of getting 4" diameter UHMW instead. This should fit the ID of the spring pretty close and should keep the coil in its channel at droop better.
I was planning on just using hockey pucks for the lower bump stop, but I'm thinking of getting 4" diameter UHMW instead. This should fit the ID of the spring pretty close and should keep the coil in its channel at droop better.
It's time to start figuring out that high steer arm, but I needed to figure out how to retain the position I came up with for where the drag link needs to go. My fixture was attached to the portion of the arm that needs to be cut off. Here's what I came up with:
That worked out! Now I have a pilot hole to use later on and a reference surface to build to.
That worked out! Now I have a pilot hole to use later on and a reference surface to build to.
Did some CAD work. Thinking something like this:
Still needs some refinement, but this gives me a lot of inches of weld to the casting and if it works out, a spot to mount a hydro assist ram double shear in the future. It would be 1/4" plate top and bottom then a solid chunk of 1" thick at the end for the tapered TRE insert to go into. The hypothetical steering ram would mount between the 1/4" plates and I guess the bolt would have to just thread directly into the casting because there's no spot for a nut below. Or I could maybe mount the ram off the inside edge of the knuckle arm and get a nut on that way... this still requires some thinking.
Anyone know what the mounting tab width is for a PSC ram rod end? 1" should be enough I think?
The only drawback to mounting a ram to the knuckle inboard of where the drag link is is that it would have less leverage on the steering action and be less beneficial. Does it matter? IDK. I might not even need (haha, "need"...) ram assist with the larger JL steering gear, but we'll see.
Still needs some refinement, but this gives me a lot of inches of weld to the casting and if it works out, a spot to mount a hydro assist ram double shear in the future. It would be 1/4" plate top and bottom then a solid chunk of 1" thick at the end for the tapered TRE insert to go into. The hypothetical steering ram would mount between the 1/4" plates and I guess the bolt would have to just thread directly into the casting because there's no spot for a nut below. Or I could maybe mount the ram off the inside edge of the knuckle arm and get a nut on that way... this still requires some thinking.
Anyone know what the mounting tab width is for a PSC ram rod end? 1" should be enough I think?
The only drawback to mounting a ram to the knuckle inboard of where the drag link is is that it would have less leverage on the steering action and be less beneficial. Does it matter? IDK. I might not even need (haha, "need"...) ram assist with the larger JL steering gear, but we'll see.
The steering box on my JL seems to handle 37's pretty easy. But on the rental fleet (with 33's) I have seen them get so hot they boil over.
That's valuable info, I think I'll end up with at least a cooler before long.
Regardless of whether I get a ram, I need a spot to put a stabilizer anyways. I'm not done designing the mount yet but I think I'm onto something...
Alright so I made some progress on my steering arm idea. Converted the CADboard to actual CAD, printed it out in PLA, then mocked it up after a few iterations. Not sure this will be the final design yet, but I'm close enough to see if everything fits nicely. The construction will be 1/4" top and bottom plates, then a milled out chunk of 1.25" steel in the middle. That's gonna be a tough task in my mini mill, but I have a feeling it'll be alright.
The drag link would go into that tapered insert, then the double shear part of the bracket would be for a steering damper, or possibly in the future, a hydro assist ram.
I don't want to cut any steel yet. I don't actually have the tie rod ends I'll be using yet, those should arrive Saturday. Once I confirm those fit, then confirm the position of the double shear mount works, I'll go ahead and cut the parts out. Would be great to send this off to SendCutSend, but I really don't want to wait on the parts.
The drag link would go into that tapered insert, then the double shear part of the bracket would be for a steering damper, or possibly in the future, a hydro assist ram.
I don't want to cut any steel yet. I don't actually have the tie rod ends I'll be using yet, those should arrive Saturday. Once I confirm those fit, then confirm the position of the double shear mount works, I'll go ahead and cut the parts out. Would be great to send this off to SendCutSend, but I really don't want to wait on the parts.
I've been busy with non-jeep stuff the past few days, but my Metalcloak dog leg TREs came in. Threw one on real quick to see how it looks, and I think everything might clear just fine. Need to trim a tiny bit more off the knuckle casting though.
The TRE might interfere with the stabilizer bolt, but the joint also will point down and away from it as it steers towards the bolt due to the steering axis at the ball joints, so it might just sneak on by.
Looks like it gets to a nice steep angle before it hits the rim, though a 1/4" wheel spacer might put it in a better spot if it isn't enough.
Here is the size difference compared to a normal 1-ton joint from Synergy
The shank is larger at 1" instead of 7/8", but the actual joint is the same size:
Metalcloak doesn't actually list these for sale on their website, but I was able to purchase the pair by emailing them. Hopefully they hold up, they seem like good quality!
The TRE might interfere with the stabilizer bolt, but the joint also will point down and away from it as it steers towards the bolt due to the steering axis at the ball joints, so it might just sneak on by.
Looks like it gets to a nice steep angle before it hits the rim, though a 1/4" wheel spacer might put it in a better spot if it isn't enough.
Here is the size difference compared to a normal 1-ton joint from Synergy
The shank is larger at 1" instead of 7/8", but the actual joint is the same size:
Metalcloak doesn't actually list these for sale on their website, but I was able to purchase the pair by emailing them. Hopefully they hold up, they seem like good quality!
Cut another chunk off my knuckle:
Cut an even smaller chunk off my other knuckle:
Joint now clears the casting at the max angle it will see when steering, unless I adjust the steering stops for more:
Here is the general idea:
The steering stabilizer might pose a couple issues being here, mainly the bolt hitting the TRE shanks and the drag link might collide with it at full stuff. Still need to move the axle around and see if it will be an issue before making it out of steel. Worst case, the drag link portion of the arm is perfect so I can just mount the stabilizer elsewhere if needed and remove that portion of the mount.
Cut an even smaller chunk off my other knuckle:
Joint now clears the casting at the max angle it will see when steering, unless I adjust the steering stops for more:
Here is the general idea:
The steering stabilizer might pose a couple issues being here, mainly the bolt hitting the TRE shanks and the drag link might collide with it at full stuff. Still need to move the axle around and see if it will be an issue before making it out of steel. Worst case, the drag link portion of the arm is perfect so I can just mount the stabilizer elsewhere if needed and remove that portion of the mount.
Not gonna lie, I panicked a little yesterday when I mocked up the tie rod at full stuff and saw this:
A couple things working against me in this pic though are that I stuck larger 2" PVC on there for mockup and the pitman arm itself was biased to the left side. I removed the pitman clocking key and rotated it right one tooth which gives me more front to back clearance when turning fully left. I really almost bought Rancho knuckles! I don't really know why JK/JL pitman arms have that offset to them, maybe just so the link can be an inch longer.
Clearances are still extremely tight with it so high up. I don't know if I measured something wrong when planning it out or what but I wasn't expecting it to be higher than the pitman arm joint. After thinking about it for a bit, I think I've devised a plan that should work and maintain optimal geometry.
Full stuff full right turn is ok, everything clears:
Full left turn is a bit tighter though:
Same viewed from the front:
Before, I was planning on just running straight aluminum bar for all 3 linkages with double adjustable ends, but I don't think there's any way around doing a bent trackbar. The bar needs to go over/in front of the diff cover then sneak under the pitman arm bolt. I threw my old currie track bar up there, and it does seem like it will work with a fairly similar shape. The frame side joint has enough space to live between the fully turned tie rod and the spring perch and can still be in line with the pitman joint. I've never bent tubing before so hopefully I can make it work on my shop press. Not aware of anyone locally that does that sort of stuff.
Good news is the high steer arm on the knuckle seems like it is going to work perfectly, so I think I'll go ahead and tackle that soon. Got a new Monroe stabilizer to put there, and that also seems like it will clear everything.
A couple things working against me in this pic though are that I stuck larger 2" PVC on there for mockup and the pitman arm itself was biased to the left side. I removed the pitman clocking key and rotated it right one tooth which gives me more front to back clearance when turning fully left. I really almost bought Rancho knuckles! I don't really know why JK/JL pitman arms have that offset to them, maybe just so the link can be an inch longer.
Clearances are still extremely tight with it so high up. I don't know if I measured something wrong when planning it out or what but I wasn't expecting it to be higher than the pitman arm joint. After thinking about it for a bit, I think I've devised a plan that should work and maintain optimal geometry.
Full stuff full right turn is ok, everything clears:
Full left turn is a bit tighter though:
Same viewed from the front:
Before, I was planning on just running straight aluminum bar for all 3 linkages with double adjustable ends, but I don't think there's any way around doing a bent trackbar. The bar needs to go over/in front of the diff cover then sneak under the pitman arm bolt. I threw my old currie track bar up there, and it does seem like it will work with a fairly similar shape. The frame side joint has enough space to live between the fully turned tie rod and the spring perch and can still be in line with the pitman joint. I've never bent tubing before so hopefully I can make it work on my shop press. Not aware of anyone locally that does that sort of stuff.
Good news is the high steer arm on the knuckle seems like it is going to work perfectly, so I think I'll go ahead and tackle that soon. Got a new Monroe stabilizer to put there, and that also seems like it will clear everything.
I see they even managed to get their logo onto that little TRE. #facepalm
Nice work on the build! I enjoyed that read.
Thanks! I know, right! Someone on here got a Metalcloak diff cover and took the time to grind off the giant M in the casting. I'm not going that extreme on some TREs though..
I made a bit of progress on that steering arm. 1.25" steel takes a while to cut!
I should have spaced the drilled holes closer because the sawzall part of that was not fun.