rear suspension ides

pokey · Nov 26, 2007

As I am putting the rear suspension together on the jeep (spring over yj springs) I have came across a couple of ideas (from wildhorses) One is a spring plate that is radiused so as the spring drops it dosent bind on tthe sharp edge of the plate and created a stress point. Now I have had a yj spring over on the front for years and have never had any issues with breaking a mainleaf here but it does seem like a good idea. Thoughts?

The second is I feel I will most likely need a traction bar of some sort on the rear. Againg wildhorses sells a neat product that is designed to weld to the top of the center section of a 9" and mount to a cross member on the other end. My thought was to use a thick aftermarket cover with a tab on top (like they use for the linked rear ends.) and attach a bar from there to a crossmember using a shackle on the crossmember end. Thoughts on these ideas?

Grommit327 · Nov 26, 2007

pokey said:
As I am putting the rear suspension together on the jeep (spring over yj springs) I have came across a couple of ideas (from wildhorses) One is a spring plate that is radiused so as the spring drops it dosent bind on tthe sharp edge of the plate and created a stress point. Now I have had a yj spring over on the front for years and have never had any issues with breaking a mainleaf here but it does seem like a good idea. Thoughts?

The second is I feel I will most likely need a traction bar of some sort on the rear. Againg wildhorses sells a neat product that is designed to weld to the top of the center section of a 9" and mount to a cross member on the other end. My thought was to use a thick aftermarket cover with a tab on top (like they use for the linked rear ends.) and attach a bar from there to a crossmember using a shackle on the crossmember end. Thoughts on these ideas?

That wouldn't work with only one track bar on a shackle...the axle would still be free to rotate under torque. You need to use a triangular setup with two mounting points on the axle if you use a shackle type setup

pokey · Nov 26, 2007

Grommit327 said:
That wouldn't work with only one track bar on a shackle...the axle would still be free to rotate under torque. You need to use a triangular setup with two mounting points on the axle if you use a shackle type setup

So do you suggest mounting it the way they show in the pic? Dosent the axle tend to move back as it gois up? (shackles on rear of spring) wouldnt fixing the end as shown cause stress on the front half of the springs as the axle rises since it cant move back?

64FJ40 · Nov 26, 2007

The problem with the single-bar type of anti-wrap setup is that it still relies on the spring packs as the other half of the linkage triangle. Not an entirely bad solution if you have stiff springs, but YJ springs are soft and will still wrap up in this setup.

Go for the trianglulated truss with a shackle at the crossmember end - just put it off-center to whichever side works best for ya.

CrustyJeep · Nov 26, 2007

64FJ40 said:
Go for the trianglulated truss with a shackle at the crossmember end - just put it off-center to whichever side works best for ya.

It needs to be on the passenger side.

pokey · Nov 26, 2007

CrustyJeep said:
It needs to be on the passenger side.

Why? is it the theroy(sp) that forward torque moves in a righthand rotation?

64FJ40 · Nov 26, 2007

CrustyJeep said:
It needs to be on the passenger side.

Jeep thing?

Outback · Nov 26, 2007

pokey said:
So do you suggest mounting it the way they show in the pic? Dosent the axle tend to move back as it gois up? (shackles on rear of spring) wouldnt fixing the end as shown cause stress on the front half of the springs as the axle rises since it cant move back?

If you run the type of link that is shown in the picture then both ends must be solid. The way it works is the mount that is mounted to the axle will rotate around the center-line of the axle (side view). The solid mounted bar will resist/stop the rotation. However if you put a shackle on ether end of the bar in the picture then the axle will rotate because in effect the shackle allows the bar to become longer and shorter.
If you do not run a shackle at some point the bar as shown will bind up the suspension and limit travel.
To run a shackle you need to solidly mount the bar to the axle above and below the axle centerline. Doing this will cause the bar to rotate with the axle. If you then solid mount the bar to the frame you will have no wheel hop and little travel. Put the shackle at the frame end and then the bar will be able to move front to back, to follow the axle/springs but; not rotate to counter the wheel hop. Note that the two mounts can be above the housing but the mount can be a PITA to fab. Just try to keep them at least 6" apart.

82toyomud · Nov 26, 2007

64FJ40 said:
Jeep thing?

Counter act the rotational moment?

64FJ40 · Nov 26, 2007

82toyomud said:
Counter act the rotational moment?

It shouldn't matter where along the housing the bar is mounted if the axle is assumed to be a solid piece. I don't think Jim is running an unwelded AMC20, so maybe there's something on the driver's side that would be in the way???

82toyomud · Nov 26, 2007

64FJ40 said:
It shouldn't matter where along the housing the bar is mounted if the axle is assumed to be a solid piece. I don't think Jim is running an unwelded AMC20, so maybe there's something on the driver's side that would be in the way???

True, but it would make life much easier if it were mounted farther from the center of rotation... You should know that:fawkdancesmiley:

64FJ40 · Nov 26, 2007

82toyomud said:
True, but it would make life much easier if it were mounted farther from the center of rotation... You should know that:fawkdancesmiley:

You're just talking about separation from the rotational axis in the rotational plane. Easiest to just use a bracket like this one:

That has nothing to do with where it's mounted longitudinally along the housing. If you control wrap at one end of the housing, you control it along its entire length and the forces are identical. Ideally, it would be in (or toward) the middle. Not that it makes a difference for the anti-wrap function, but to reduce the amount of vertical travel you have to accommodate with shackles and/or bushings.

CrustyJeep · Nov 27, 2007

64FJ40 said:
It shouldn't matter where along the housing the bar is mounted if the axle is assumed to be a solid piece.

You are thinking about just the axle. Think about how the axle relates to the vehicle. Bring the drive line into the equation. Think about which way the vehicle leans under torque.

Outback · Nov 27, 2007

CrustyJeep said:
You are thinking about just the axle. Think about how the axle relates to the vehicle. Bring the drive line into the equation. Think about which way the vehicle leans under torque.

You done run this trail once. :haha:

pokey · Nov 27, 2007

Jobless said:
Fawk Jim...do you really have to ask...4-link and coil overs

:fawkdancesmiley:

cool idea are you buying this for me for x-mas:cheer:

pokey · Nov 27, 2007

64FJ40 said:
It shouldn't matter where along the housing the bar is mounted if the axle is assumed to be a solid piece. I don't think Jim is running an unwelded AMC20, so maybe there's something on the driver's side that would be in the way???

flanged axle 44:cheer: Nothing really in the way but I do seem to see a lot of thes on the passenger side.

crash2 · Nov 27, 2007

64FJ40 said:
The problem with the single-bar type of anti-wrap setup is that it still relies on the spring packs as the other half of the linkage triangle. Not an entirely bad solution if you have stiff springs, but YJ springs are soft and will still wrap up in this setup.

Go for the trianglulated truss with a shackle at the crossmember end - just put it off-center to whichever side works best for ya.

I ran that setup for a # of years and it did decent for what it was--and yes you rely on the front half of the spring pack...

NotMatt · Nov 27, 2007

Here's how I did mine... Worked great with soft YJ rears, no issues with binding or travel. You need a good solid crossmember to mount it to, the stock belly pan won't do. I put a couple bends in a piece of 1.5" tube and welded it to the bottom of the frame rails... it hangs down a bit, but not lower than the stock belly pan. One day I will re-do that part. I mounted mine on the passenger side as close to the diff as possible... just enough room to get in and weld between the bracket and the diff.

In my opinion, this is the only way to effectively control axle wrap with leaf springs. Every other method is simply a band-aid fix that either hinders suspension travel or relies on the stiffness of the spring to aid in controlling wrap.