Need opinions on a brake problem

[98MNChevy]

Alright guys, I haven't had a chance to go take a look at my brakes yet, so it may be something really simple and obvious, but I figured I'd still ask and see what you guys think my problem might be. Currently, my brakes on my 1998 K1500 are either super, super sensitive or really crappy. Honestly, sometimes I barely touch the pedal and they lock up on me and the next time I basically have to stand on the pedal and I still don't slow down. Usually the brakes are really sensitive soon after starting the truck up and for a few minutes after I start driving. I do park outside so that might be partly related to what is happening, but I am not sure. Like I said, I haven't even checked my brake fluid, and that may be all that I need to do, just haven't had the time to check.

Any ideas about what may be happening is appreciated!

-Nick

 

[Scrufdog]

sounds like metal on metal, likely in the rear brakes. Front brakes generally just grind and make noise. Worn rear drum brakes tend to jam up, especially in high humidity/rain until warmed up.