[Stonefly]

SOA on a 91YJ.

On the D30, would mounting new perches on top of the axle tube, parrallel to the stock perches, give me the correct angle? Axle is not under the Jeep.

 

[RedDonkey]

Are you doing a spring over? If yes then you should put the axel under the jeep and bolt it down like you would if the spring perches are welded on. then tack them down. that way you can set up the perfect pinion angel..

 

[Stonefly]

I'm not able to place the axle under the Jeep today, for a test fit. Just need to know if welding the new perches parrellel to the stock perches will give the correct pinion angle. Stock YJ 5-leaf spring packs will be used front & rear. If so, I can weld them on & cut off the stock perches & shock mounts tonight. Anyone else?

 

[mudtoy67]

I'm not able to place the axle under the Jeep today, for a test fit. Just need to know if welding the new perches parrellel to the stock perches will give the correct pinion angle. Stock YJ 5-leaf spring packs will be used front & rear. If so, I can weld them on & cut off the stock perches & shock mounts tonight. Anyone else?

In theory you should be just fine. The concern on the front is not as much the pinion angle it is the caster angle. If you weld the perches on top of the axle at the same angle as the originals, you should be close enough.

 

[RedDonkey]

you can di that but i would give it aleast a 10 deg. up angel on the pinion. that will save u joints..

 

[1972CJ5+1]

you can di that but i would give it aleast a 10 deg. up angel on the pinion. that will save u joints..

Well not really. Depends on what kind of driveshaft you have. If it is a CV, point it at the output. If it isn't, you have to cancel eachother out.Take a step into the Pirate Tech Section

 

[CrustyJeep]

But then you must consider that this is the front axle. Just don't drive around on the hiway with the hubs locked in, and the drive line can be as unbalanced and unphased as you please. Point that sucker up if you can, big deal.

It's all about the caster angle,

 

[Stonefly]

CrustyJeep is correct. This is the front axle (D30). The stock (single-cardan) driveshaft will be retained. Dug up the Chilton manual. Stock (SUA) configuration, with a manual transmission shows caster should be set to 8* positive. With the axle mocked up (no load) @ 8* positive caster, the stock perches are @ 0*. Reading through the Pirate Tech, the geometry should hold true in an SUA or SOA configuration. Thanks guy's.

 

[Nor Cal Jeep]

I just finished my SOA and i set my front pinion angel parrallel to my transfercase output.
BTW, I tried to use the stock YJ 5 leafs in the front and it sat lower then in did when i had my Pro Crap SUA lift. So I ended up mixing stock YJ's with the procomps and now i like the way it sits.