YJ Spring under conversion

[MacCoul]

Hi newbe here. I have a 76 CJ7 that is running 35"tires and has 4 inch springs. I have been searching for some review or info about swapping out to yj springs but keeping it spring under. All the write ups i have seen have been spring over and no spring under. I mostly am looking for to know if its worth it to make the swap with out going over as far as ride gees. It will simplify dealing with the steering and such. Thanks in advance. P.S. my jeep is mostly used for 2 track and back roads exploring....Nothing extreme where max flex is needed...at this time

 

[Posi]

Welcome,

I went spring under with 3" yj springs and it's not uncommon. I don't recall doing anything special besides move the steering box forward an inch and swapping from CJ to yj spring frame hangers.



Swap out the CJ hanger to the wider yj hanger in the front only.



You can buy an aftermarket bracket to move the box forward an inch





I had to notch my front crossmember





Hard to see but I added some 1/4" under the notch for added support.

 

[MacCoul]

Did you drive the jeep with cj lift springs befor swiping out to yj? If so, How would you compare the ride?

 

[Posi]

The CJ I installed the yj springs had stock CJ springs previously. I had a CJ with a 4" lift and didn't like the ride at all, like riding on 4 big "U"s, harsh ride IMO.

Swapping from a CJ4 " lift to a 4" yj spring under in the later 76-86 CJs isn't a big improvement because your only changing the width, and about 1" of length of the front springs (2" 22 1/16" to 2.5" 22 11/16") The rear CJ springs are the same width and basically the same length CJ 22 9/16" to yj 22 11/16". The 75 and down there is a big improvement when swapping to yj springs IMO.

4" CJ springs work for some, but I would never go that route. There is plenty of options with some work you can move the frame spring hangers and go with longer springs, remove some leafs from your current pack, mix and match. Some other simple things like using the correct torque on your shackle bolts and running 20-22 psi in your tires.

But to answer your original question, would swapping out your SUA CJ4 " springs to SUA YJ 4" springs be worth the improvement? Cost vs improvement, I would say no.

 

[MacCoul]

Thank you for the info, that was my guess as well that there was not going to be a big improvement. I may just do a spring over in the front and leave the rear spring under for now until i can plan out a rear axle swap. The 20 is a time bomb for what I'm pushing for power and axle wrap will be an issue. The only rear issue I have with spring over is dealing with steering correction.

 

[Posi]

Yes, there is work involved with SOA, steering, spring pads, and a traction bar in the rear so don't damage the springs. I did a SOA with wagon springs on my wheeling rig.

If you haven't already try torquing the shackle bolts to 20ft lbs, and tire psi to 20.