I've read a few DIYs on this and they all state to "bump the starter" with the lines to the cooler undone... What exactly for dummies does "bump the starter mean"? Does it mean to start the truck and quickly shut it off?

Other question is, does the truck need to be started to bleed the lines?

 

I just changed the lines and whole rack and pinion. All I did to bleed the system was disconnect the lines at the gear and the cooler. Let gravity pull all the old fluid out the lines. Of course I changed the whole gear so all I had to do was install the new lines, refill my resivoir and start the truck and turn it back and forth for a few minutes. Turn the truck off, refill the resivor and start the process over. Eventually all the noise will quit and the steering will get easy again. In your case I would. Disconnect the line from the gear to the cooler. Disconnect it from the gear. Start the truck and turn it from side to side till all the fluid runs out. Put lines back together, refill resivoir, start truck up and steer back and forth for a few minutes. Turn truck off, refill resivoir, start truck again, start steering back and forth. Repeat that process till it stops making noise and is easier to steer again

 

I am assumming bump means just turn the key so the motor turns but does not start. Just turn the key quickly and back. If you let the motor start the pump will literally "fire" the fluid out of the return hose. I learned that one quickly the other day and having to scrub my driveway for hours.

I flushed my pump and went through two quarts in a matter of seconds flushing out the system. Not sure what your manual says but my 05 says to use ATF-4 and not power steering fluid which is good as far as cost goes.