Thanks Fred ... I'm really just in the process of figuring all this out, so any advice from Stovebolters is appreciated. Brakes failed again last night. The pedal just went straight to the floor. Checked the m/c and just air in there. darn ... I was watching the fluid levels like a hawk. Was a couple of miles from home, so added some brake fluid, pumped the brakes a bunch and got a little pressure, so drove home slowly. Very slowly. This truck ain't leaving the driveway again until this is fixed for sure. I can't risk it.
Figure I'll test the m/c to see if it is bad (not that I know how to do that either, but hey ... got to learn sometime) and make a list of other components so that I can figure out what exactly the problem is here by a process of elimination - before I start replacing anything.
Any advice on what that list should look like (in order of priority) would be really, really helpful.