Brake problem

I have a problem with my brakes on my 02 JGC Laredo. Back story-car hit a curb a few months back, and I had to replace my rear caliper, backing pad, and brakes of course. Both the front driver and rear driver were messed up, but the front driver didn't need anything replaced. Recently, I applied pressure to the brake pedal to stop at an intersection, and the brake pad felt squishy. The pedal would go down, and while I was stopped, it would continue to go down to the floor. The brakes seemed to work though, only the pedal would continue to go down. Also, in traffic, after constantly applying pressure to the brakes, the pedal would go all the way down to the floor when I pressed it, SCARING the hell out of me! I would pump it, and it would work, stopping the car, but this is a VERY serious Safety issue, that I need to get fixed, i just want to know what the problem could be and how much it would cost me to fix it. Also, is the problem an easy fix, something I can do myself?

either a hole in one of the lines (leaking brake fluid) or air in the system.

could even be a bad master cylinder and fluid is leakking past the seal.

It Coud Be That You Have Air On Yhe Brake Lines And What You Need To Do Is Bleed The Brakes Because You Have Air On The Line And Also Check For Any Leaks Off Brakes Fluid On The Lines

This sounds similar to a problem a had not too long ago. I know this may sound wierd, but you might wanna have your wheel bearings checked out.

My problem was similar in that the brake pedal would sink oddly as i applied pressure to the brakes. If i slammed the brakes or pumped them, they would tighten up for that moment. I also noticed later on as it progressed that it would happen a lot more often, and much worse when i turned the wheels one direction as opposed to the other. What i found out was my wheel bearing had gotten so bad that it was separating, and literally the wheel, along with the rotor, would pull away from the car, thus causing more distance between the inner brake pad and the rotor. The result of this is that in order for the pads to squeeze the rotor, the have move in farther, and tighten alot more, thus requiring more of the brake pedal to be pressed in order to do so. When i had the bad wheel bearing replaced, the problem went away.

P.S. dksob, With the exception of the specialized grille for the 5.9's, your front end looks identical to mine in that picture. Lights and all.