What's up with my rear brake? pic included

I replaced my rear pads/rotors in December; I discovered my driver rear caliper was bad too, so I had that replaced. Fast forward to present day and the caliper I bought froze and I had to again replace the bad caliper, the rotor, and the pads.

After replacing I could hear noise from the driver rear brake, but my buddy who replaced everything said it was normal to hear some noise, as the pad and rotor are breaking in. It was when I noticed that the noise would not dissipate or change in tone when I pressed the brakes. I took a look and saw, that after driving, there was still rust on the rotor and only the very edge was making some kind of contact.

As I type this my friend is driving to Texas, where he is relocating, so I have to figure this one out on my own (with the help of you).

Any help would be highly appreciated!

 

Do you know the caliper was bad, or did you just assume that? The first thing that comes to my mind is a blockage in the line preventing the caliper from operating.

 

I am going by my friend, who pulled everything apart, before I bought another one. The pads were worn to the pin. I was thinking maybe something to do with the line; I can do basic maintenance stuff, but I'm not super knowledgable when comes to pinpointing stuff like this.

 

What vehicle Is this?

 

I've never seen a Tacoma with disc brakes on the rear. Is this a rear disc brake conversion?

 

Sorry, this is my 06 Civic lol.

 

It's possible that there are a couple of things at play. (1) If you were buying re-man parts, it's not unheard of to get 2-3 bad ones in a row, especially if they're bought from a discount supplier. (2) Or, you may have a partial blockage in the line which, because that caliper isn't doing much work, meaning that it gets stuck more quickly than it would under normal operation. Is there a flex line to the caliper or is it a hardline all the way?

 

I'm not sure if it's flex line or hard line. The first caliper was bought from Rockauto. The 2nd one was bought local at Carquest.