Ok so this is the problem, i replaced my brakes / rotors about 2 weeks ago and the car have been sitting in my driveway since then, so with the car been sitting so long there is rust on the rotors which is nothing; i took the car for a drive today and my back left driver side rotor still had rust in it while the other 3 tires rust was clean off when i pressed on the brake.

So now i want to know why is does the back left driver side rotor still have rust on it

More info- when i changed the brakes the back left driver side caliper wasn't frozen.

 

When you compressed the piston did you see any noticeable rust surrounding it? maybe the piston isn't releasing and the pad is not making contact. Any noticeable drop in braking performance? If not, I wouldn't worry about it.

 

Im gonna check the piston tomorrow, But there is a slight drop in the braking performance

 

Maybe spray some pb blaster on it and and hit it with a wire brush the best you can. Also make sure the pad is securely clipped in. I didn't use a brake lube? Or whatever it's called and now when I come to a stop I hear a click.... so annoying but not detrimental, I'm gonna do a pad slap in the rear when I change my front rotors and pads and I'll use whatever grease I'm supposed to. Did you bleed the brakes or just uncapped the brake fluid reservoir and slowly compress the piston?

 

Maybe the hose is collapsed internally?

 

Whatever the problem is, and there is one, that caliper is not clamping on the rotor.

 

Brilliant deduction. Any thoughts to actually help the Op other than rubbing salt in his wounds? Lol

 

Any resolve for this problem yet?

If not, I would start by checking the hardware. Make sure that the pads are not binding on their mounts. If good, check the caliper to see if there are signs of internal corrosion or other mechanical issues. If no luck there, the hose would be good next choice.

I replaced my brakes after finding out one of the rear calipers has seized on me...only after I had to hit the brakes rather hard to not hit an idiot driver. That piston didn't want to retract itself easily. It did manage to go. Being lazy, I haven't rebuilt/replaced it yet, but it is being watched carefully for operational issues.

Some problems have no easy answer other than to inspect it and determine what it is.

 

I'd bet that either the caliper guide pins are seized, or the piston is seized.

Rear calipers seizing is COMMON on the G35. They just sit too low on the rotor, and accumulate moisture. Since rear brakes do less work than the front, a quick drive never really gets them hot enough to bake out all that moisture out.

Pull the caliper off, and see if you can slide the guide pins easily. If they don't move, they are seized. Your options are to try and free them and relube with silicone caliper grease, or just buy a reman caliper from parts store and replace it. Rear calipers are cheap as Nissan used the same caliper on many of their cars in the mid 2000's. I think Altima, sentra, M35 all share the same rear caliper.

I drove my car to 180K miles. Over that course of time, I replaced 3 rear calipers. When I saw the signs they were sticking, it was just easier to swap the caliper, vs trying to clean and relube it. I think calipers were $35 plus core.