Ive noticed a massive amount of rust on my rear passenger side wheel. I'm not sure where it's coming from or how it happened. Also that one side is grinding when I'm braking. It sounds like metal to metal grinding but I have pad life left. I'm not sure if there's something more that I'm missing or I should just replace it all together. Plus the rotor itself is looking pretty bad as well.

 

I suspect your caliper is sticking/seized on the two pins that it should slide on to compensate for pad wear.
When this happens, the outside pad is ok, and the inside pad worn down to the metal backing plate.

Common issue because most don't clean out the old grease/rust and add new grease to the caliper pins during a brake job.

 

Thanks for that! Makes sense now. Should I replace the whole caliper or try to re-grease the pins?

 

I agree with Sonic, caliper probably seized and it killed your inner pad. If you hear grinding means that the inner pad is done and it's grinding metal on metal which is why you're getting this rust.

You'll need to get a rotor, pads and keep an extra caliper handy incase you can't free it. Freeing a stuck caliper can be a 50/50 chance.

Though I've forced many of the calipers I've worked on loose, I also live in Florida and don't deal with with the rust that colder climates see. It's still a messy/heavy job at times worth less than buying a new one especially if they're not sport brakes.

 

The caliper is fine and won't be difficult to remove... Just 2 12mm bolts...
BUT the caliper pins that slide into the "torque member" or caliper bracket.. that might be your challange.
Usually the top pin can be removed without much problem, but the lower pin will have much more corrosion and can be much more difficult to remove.... assuming that is your issue.

The only way to find out, is to get your hands dirty.

 

Thanks for the replies guys. Great help. I decided to just get a new caliper from rockauto. Going to use this as an excuse to start doing my own brakes.

 

I am having a similar issue. 2013 G37X, Driver rear caliper had the lower pin seized. Trying to replace the whole caliper but now having difficulty removing the brake line connection to the caliper. Any suggestions on how you removed the brake line from the caliper??

 

Common problem because most people who perform brake work fail to remove the old oil and corrosion and put fresh grease on the caliper pins. Are you a student and you have been given to make assignments on Methodology? But you don't know how to write about it. And you want your dissertation methodology chapter to be written by an expert. So you can solve your problem by taking the help of the post.