Slick film on rotor and caliper

Good evening! I've noticed a pull to the right when braking, so I pulled the driver's side tire and found the rotor and caliper covered in a slick film. Obviously this brake has been rendered ineffective; however, I'm not sure where to begin looking for the culprit. Brake fluid is where it should be. Also, there is an awful popping and/or clunking when I'm driving slowly and turning sharp. The truck is a 2004 2WD with the 3.7--approximately 74K miles. Ball joints and tie rod ends on both sides? Thanks for your input.