Do you need alignment after changing lower ball joint?

[mikepier]

99 XLT 4WD. Just curious, is it necessary to get an alignment after replacing the lower ball joints? I was thinking of tackling this project one weekend and was curious if the alignment is affected at all.

 

[gijoecam]

In theory, you *shouldn't* need one, but in reality, it's not a bad idea. Slight variations from one ball joint to another could change the position of the knuckle with respect to the LCA, which would affect caster, camber, and toe angles.

On a side note, I've always wanted to try an experiment: Get an alignment check before and after a lower ball joint replacement, just to see how it changes. It's more morbid curiosity than anything.

 

[ld50]

I would think any slight variation would be within the acceptable + or - of an alignment anyway. There is no way to have everything absolutely dead on, they align to an acceptable degree. An alignment wouldn't hurt for piece of mind, maybe it was out of align for a long time before.
I wouldn't bother though unless I had uneven tire wear or symptoms of poor alignment.