Background info: Rancho 4 inch lift with 18x9 +20 wheels and 285/75/18 tires.

Ok, so I've ran this combo since April with no problem until this morning when backing out of my space at work, turning left at full lock I had rubbing on the right tire with the front bumper. I had an alignment about a month ago but the only thing that's been out of the ordinary lately is having to drive through high water in 4Hi (I'm in Houston.) I measured with the wheels straight and the right wheel is very slightly more forward than the left. Is this just an alignment issue and easy fix or is something else going on? Thanks.

 

Sorta sounds like alignment. Driving thru the high water in itself isn't gonna knock it around, it's what you can't see under that H2O.
Do you recall falling in any holes, hit a curb or something else? I don't wanna know what that something else may have been.

 

When you adjust caster it effects the fore and aft positioning of the wheel in the wheel well, having the lower control arm shift in it's mounts after an impact from a pothole or some other obstacle can easily happen and cause this.

 

Are you sure it is rubbing on the bumper and not on the inner wheel well skirt forward of the coil spring top?

That's where my 285/65/20 tires rub with a 2.5" coil spring lift when the steering wheel is full left lock.

 

Castor isn't the problem, my toe was way off. Is there anyway to keep my alignment from drifting so often? I had just had one done a month ago. They lifetime alignment at Firestone has been a lifesaver.

 

If your toe was way off and nothing was bent then your caster/camber bolts allowed the lower control arm to shift in its the mounting slots, even a slight change in camber or caster that seems insignificant can greatly effect your toe. If you don't have aftermarket bolts with cams on them to help prevent slipping this is something that can happen very easily, your drop cross-member that came with the lift kit may have them for the lower arms to prevent them slipping, but the upper mounts where the cross-member itself bolts into the truck often doesn't and as such it can easily get knocked back and forth in the slotted mounting holes.

They can also slip if the shop isn't torquing them down to the full 258lb-ft they call for, and as someone who works in the industry and sees what other people do all day long I can almost guarantee that they aren't.