Brakes master cyl. swap

[69halfton]

well, summer holidays are here. with that means summer job, and with that means i have money again to do some much needed maintenance work on the ol' girl.

so i picked up a new master cyl. for my truck last week, and im going to be installing it tomorow. (how much do you normally pay for a master? i will have paid 43 bucks once i get the refund for the old one)

I remember somebody on here talking about "bench bleeding" the master before installation. what the heck is "bench bleeding"

i also heard that it its a must or else i would wreak the seals or something? its all very foggy lol..

My plan was going to be install the new one, fill it with fresh fluid, and then open all the bleeders and let gravity do its work, slowly flushing the lines. as the bleeders begin to bleed clean fluid, ill close it so that the next one farther down the line will recieve its fluid.

do i need to "bench bleed"? or is the gravity thing going to sorta do that when its in the truck?