I looked around on other pages and forums, but could not find the solution to the problem so I am posting it here. After I finished putting the pads and rotors on, the brake pedal was very spongy and there was no brake pressure to stop the vehicle after it started moving, even after compressing the pedal 20+ times before driving. I checked the master cylinder but it was fine. I've never bled brakes before, could there just be air in the system and that is what's causing it? I cracked one of the bleeder valves to hopefully relive some pressure so I could compress the pistons but did not leave it open for very long, and I replaced the fluid that it did use. Any help is appreciated and thanks.