Front spring is curved

[Jackjack97]

I recently installed a 4.5 inch lift with long arms. The front spring on the passenger side is curved forested and the spring actually rubs on the perch. The driver side of s curved forward a little but not much. I beleive the axle needs to come forward some. But my main question is why Is the passenger side worse than the driver side and both lower control arms are same length as well as the axle is in the same place on both sides in comparison to the frame. Pic of drivers side. In the pic it’s not quite at ride height but it’s just as bad at ride height. I also now have the track bar and steering linkage in

 

[someguysjeep]

the axle travels in an arc and it moves toward center rig at full droop.
did you make sure the bumps line up on both sides at full compression? if so you are where you should be,

 

[CharlesHS]

You more than likely have fixed length upper and lower control arms.
For a 4.5" lift the control arms need to be adjusted both top and bottom to give you the best caster which will cure the curve in your springs.

 

[jjvw]

You more than likely have fixed length upper and lower control arms.
For 4.5' of lift the control arms need to be adjusted both top and bottom to give you the best caster which will cure the curve in your springs.
I am sure someone on the forum has the suggested lengths available.

The specific lengths are irrelevant.

Step one is to bring the axle up to full bump without springs installed to make sure everything clears.

Step two is to go back to ride height and set the pinion to somewhere around 0-3° low. Whatever results in some caster without vibes.

Step three is to repeat that process of checking and setting until the axle is where it needs to be.

 

[mrblaine]

Springs bowing forward at ride height have a few contributing factors.
1- axle spring perches are not mirrored, they are just flipped 180.
2- axle C's have cross caster built in, a small but significant amount.
3- axle position fore and aft.
4- frame side perches are angled slightly to tip the spring forward.

They do not wind the springs opposite so you wind up with one tail at the front and one at the back in the perch. Ideally they would be mirrored but that is silly to produce.

The cross caster leans one spring slightly more forward than the other. It wouldn't be noticeable were it the only factor.

Pulling the axle back to keep it out of trouble at full stuff contributes since the lower perch winds up behind the upper.

Some or all of those combined will cause the problem.

 

[Goatman]

If your frame has any bend in it, with control arms the same length the axle will not sit evenly. You may need to find several more points to measure that the axle isn't 'crab walking'

 

[jjvw]

If your frame has any bend in it, with control arms the same length the axle will not sit evenly. You may need to find several more points to measure that the axle isn't 'crab walking'

Put a longer bolt in the center skid holes to move the reference point down a bit. Then, with the Jeep level and flat on flat level ground, put a framing square against the axle tube and measure back to the extended frame bolts on either side and adjust. The axles will be parallel to those bolts and the axles will be parallel to each other.

 

[Jackjack97]

You more than likely have fixed length upper and lower control arms.
For a 4.5" lift the control arms need to be adjusted both top and bottom to give you the best caster which will cure the curve in your springs.

I have adjustable long arms