wheelbase/alignment/UCA's issues

After installing RE 4.5" added the adjustable upper and lower control arms. My plan was to adjust the lowers to achieve my 101.4" wheelbase, and then adjust the uppers for caster and pinion angle.

However, starting at the passenger side I have lengthened the lca to around 17" already and my wheelbase is only at 100 5/8". I am pretty certain that before I bought this years ago it had been pretty seriously smashed in the rear.

If I can't really go by stock wheelbase to figure lca length, maybe I can go by the coils relationship to the jounce? ER, I think thats what that thing in the middle of the coil is.

Any thoughts?

Bumpstop, not jounce

The problem is control arm angle. As you lift a vehicle, keeping the standard control arm mounting locations, the wheel base at ride height actually gets shorter. Making it the stock length at the new height will force the wheel forward considerably at full stuff. You may hit your fenders without trimming.

Thanks for the quick reply. When you write "making it the stock length", I take it you mean the wheelbase, not the ca?
If so, how do I determine best position for the front axle. Should I go by the coils? That lca at 17" is already over the general consensus I have read for a 4 1/5" lift.

Thanks again,
Todd

Ooops, thought I was a member. Guess not. Will have to rectify that immediately.
T

This is ridiculous hasta
I could make those lowers 19" and still not be able to obtain proper caster without the tires pushed too far to the rear of the wells.
It doesn't seem like the bumpstop should end up so close to the inside front of the spring. At full droop I am sure it would hang up on the spring.
WTF?

trekker said:

This is ridiculous hasta
I could make those lowers 19" and still not be able to obtain proper caster without the tires pushed too far to the rear of the wells.
It doesn't seem like the bumpstop should end up so close to the inside front of the spring. At full droop I am sure it would hang up on the spring.
WTF?

Click to expand...

Just wait until you have dropout on your suspension. The axle will drop and flex back causing the coil to rub on the bump stop making a rather pleasant noise. Everyone with this problem (that I know of) grinds that tiny lip off the front of the bumpstop to make the rubbing less. I actually elimitated that problem by pushing my front axle out a couple of inches with some long arms and that re-centered the coil and the bumpstop. I had to refab my UCA and make them 2.5" longer to do this.

Angle of the axle too will cause the spring to bow forward or aft (when you are adjusting your pinion angle).

cracker said:

Just wait until you have dropout on your suspension. The axle will drop and flex back causing the coil to rub on the bump stop making a rather pleasant noise. Everyone with this problem (that I know of) grinds that tiny lip off the front of the bumpstop to make the rubbing less. I actually elimitated that problem by pushing my front axle out a couple of inches with some long arms and that re-centered the coil and the bumpstop. I had to refab my UCA and make them 2.5" longer to do this.

Angle of the axle too will cause the spring to bow forward or aft (when you are adjusting your pinion angle).

Click to expand...

I am now thinking that I should just ignore the 16 7/8" lca length suggested by the tables etc, and just make the f'ers as long as I can. Then use the ucas to pull the top of the diff back where it should be.


Thanks for the post.

trekker said:

I am now thinking that I should just ignore the 16 7/8" lca length suggested by the tables etc, and just make the f'ers as long as I can. Then use the ucas to pull the top of the diff back where it should be.


Thanks for the post.

Click to expand...

It is a matter of trial and error. It took me a couple of tries to get it the best way.

Good luck and let us know how it works out.