[cadillac_al]

I have never been able to remove a broken bleeder from a caliper so I always end up buying a new one. When you get a new one and are able to bleed the front brakes the proportion valve should center itself. In my experience it isn't uncommon to have a 6ft piece of brake line with 1 foot rusted out and the other 5 ft still shiny silver. I don't have a problem with replacing only the rusty part. If you don't have a flaring tool then sometimes it may be easier to replace the whole 6ft of line. In any event you should be able to get your truck going for less than $50.