Front Brake Noise/Problem with piston

[ritalinpb]

Well...I had a rotational noise in the front wheel...narrowed it down to the brakes with initial inspection of the axle and having no problems. Its the rotors and pads making the noise. It gets louder and worse and then goes back to little noise. So I cant remember how many miles/months are on the pads/rotors (cant find the receipts) but theyre rusted pretty bad (I live in Michigan...so no surprise) the pads have life left so do the rotors. I thought this was the problem. So I replaced the pads and rotors with new ones. While inspecting the pads they wore unevenly front to back on the pad, thinner on one side and thicker on the other. So the slide needs to be lubed. The bolts were seized pretty well. I couldn't use heat as there are rubber dust seals. So I use some penetrating oil and a hammer and get them off. The slides look disgusting (rust dirty nasty grease). This is the second time I did the brakes (bought the car with 34k has 140k now) and the first time I had a friend help/mostly do them and can't remember if we lubed them or not. When I took the pads out the slide was definitely not moving back and forth. So I get them cleaned up and lubed and the piston in the caliper looks very rusted. Put it together anyway. On my way to work the next day the brake get extremely hot and I can smell a burning smell. So now to redo the brakes againIts got to be the piston now moving back and forth freely from rust/grime/failed seal or is there anything else that can go wrong so that the piston wont release the pads from the rotor all the way?

My question is do I rebuild the caliper or just get a new one or a rebuilt one. I found an online tutorial on how to rebuild hardest part seems to be getting the old piston out. I dont mind cleaning up the inside of the caliper. The caliper is pretty rusted though. I dont want to spend a lot of money on it. Price was anywhere from 30-150 which one should I get?

Thanks for the help.