Adj CA, WB, pinion angles, maybe more.....

[Carl McFly]

Background: my TJ has a 3" suspension lift (springs) and a 1" BL. Adjustable LCA's installed on all corners. Drivers side rear LCA was a bear to get in, had to persuade that side of the axle to go back about an inch. Really second guessing that decision.... I'm thinking my WB is longer on the drivers side now.... .... I was so focused on the LCA's being the same length on both sides, I didn't factor in variances from the factory build. Recently installed an SYE and my pinion angle is really close to what it should be, she just needs a lil adjustment

What I want to do now: Make sure my axles are parallel, by setting my wheelbase back to stock (94 inches or so) and set my pinion angle to play nice with my purty new Tom Woods DS

I read that the correct way to set the pinion angle is to adjust upper CA's, not lower. I'm thinking the best way is to remove the arms, keep the chassis on the ground, use a floor jack to lift the pinion as needed and then adjust the length of the UCA's to keep that angle. Set the length of the UCA's so they're (literally) a bolt in

And since WB is adjusted with lower CA's, I take some measurements and set my WB, set the LCA's to the correct length and again, bolt them in. But the LCA length will affect pinion angle, so I should make the LCA adjustments first, then move to the uppers

That sound right?

[nostaw]

I'd be careful about the assumption that setting the wheelbase to 94" is the best thing to do... Making the axles parallel is a good idea though.

When you lift the suspension it will pull the wheels towards the center of the vehicle as the suspension gets taller. As the suspension articulates the wheels travel up, but also forwards (in front) or backwards (in back) in a slight arc. Adjustable control arms help to "fix" the oddities of geometry by giving you flexibility... You need to adjust the axle centering to get the tires to stay kind of centered in the wheel opening to avoid rubbing over the full arc of motion. That means they actual wheelbase may be off from stock a bit.

Best way to get all 4 wheels lined up properly / make sure the thrust angle is right / get the axles parallel is to get a 4-wheel alignment at a shop that knows about lifted suspensions. You may be able to do it with a tape measure and some careful measuring though.

JW