SOA pinion angle w/CV driveshaft

[jimijam19K]

I'm still new to this board so let me fill you in somewhat on my build. It's the Rig in my Sig.

83' CJ7, YJ springs, I'm going SOA and have the front done and back on the ground. I have double cardan driveshafts from two different FSJs that will be filling duty as rear driveshafts. I'm tracking on having the pinion pointing up at the t-case output. If my measurements are correct I need a 10* correction when the new perches go on. Does this sound anywhere near right, I was figuring I'd need 4-6 deg. not 10.

This is what I did. With the frame on stands at approximate ride height I removed the tires and let the axle sag to- once again approximate level of new perch height. I jacked the pinion up with a bottle jack measuring the before and after angle with a mag. angle finder on the front of the yoke. Now I know I'm dealing with a couple of approximations but the heart of the question is does 10* difference sound like too much/little?

So here's my plan. The guy who does my welding lives 30miles from me, but I've got a partner with a 110v buzz box that I can use to tack weld the perches on at the aforementioned 10*. Once the axle is on and the weight back on the springs I'll see where I'm at with pinion angle. If it's good I'll throw it in the back of the truck and have it welded by someone way better than me. If not then I can make the adjustments I need.

So lastly, anybody done a similiar build that can share how much pinion correction they used/needed. Thanks in advance of any feedback.

 

[JOOP]

If you have a CV rear drive shaft you pinion should be pointing at the T-case output. Being your SOA, you might want to tilt the pinion angle down 1-2* to allow for axle wrap.

Also you want to line everything up with the axle at ride height, not sagging. Just put the jack stands under the axle.

 

[jimijam19K]

Perhaps I didn't explain well enough. I left the axle on the SUA perches and measured the pinion/perch offset. I sagged the suspension to the approx. level the housing will be at once it's SOA then rotated the pinion to measure the difference between the two. However you slice it I'll tack weld then mock-up before final welding anyway. Just looking to see if I'm way off base.

 

[Maverick26]

I have a CJ5 that i did the same build on and if you dont cut and turn the C's you wont like the way she drives at 10*. Caster is a big part of how it reacts on the road. Not sure of the caster angle spec for the dana 30 but look it up before you cut them off. Its not a tough project, but it will sure help in the end. And also again be sure to drop your rear pin. atleast 2* to alow for axle wrap. front sould have at least 1-2* also for U joints to work. Good luck with your build.

 

[jimijam19K]

Front's already welded and back on the ground. The original post was regarding the rear axle.

 

[NotMatt]

Doesn't matter what the difference in angle is, don't worry about that, it's pointless to measure it. Point the pinion just a slight bit below the t-case output, tack that **** on, then take it down the road to your buddy's house to weld it up. Done.

Oh yeah, and build an anti-wrap bar too. It's not optional if you're using YJ springs and you're going SOA.