So what causes bump steer? I thought it was drastic angle in the steering linkage but does the alignment of the steering linkage and track bar cause this as well?
Yes!
The axle does not move in a true vertical path. There is some side shifting going on due to the arc that the track bar takes. Match that arc with the steering linkage and no bump steer. Perfect match is almost impossible but really close is what you are after.
I was amazed while working mine out that ¼" of height change on the steering linkage would make a noticable difference. To get it right can take a lot of work.
The best way I found to see bumpsteer is to remove the front shocks (so you can get some good bouncing and travel in the driveway). Some vise grips and scrap metal to lock the tierod to the axle tube. That is so ALL the bumpsteer will show up in the steering wheel. Bounce the front suspension and watch the steering wheel. When you get the steering wheel to stop turning while bouncing the bumpsteer is gone.
Another thing to consider...
I mentioned the axle does not travel a true vertical path, it follows the arc of the track bar. Well when that track bar starts getting some angle to it the axle shifts off center. Some fix it with a longer/adjustable track bar. Well that centers it under the body but does nothing for the angle. When you hit a dip in the road you will experience a lot of axle shift. When this happens it feels like the suspension is crooked. The dips in the road cause the vehicle to rotate. Well the body rotates but the truck drives straight and it can do this with no bumpsteer.
There are a lot of things that can be done wrong.
I start with the basics. Is the track bar right? does the suspension travel up and down without side to side movment? Then go after bumpsteer.
My history:
Lift, springs only. No bumpsteer but now bounced sideways in dips.
Track bar riser. Drove straight in dips now but angles off on steering, bumpsteer.
Heim joint steering. (no drop pitman arm) played with over/under and some spacers. Drove great after that.