Y my breaks make noise on the rear of my g35 2004

What noise does it make?
does it also do it in reverse?

It's most probably the wear indicators on the brake pads. They make an irritating low pitched intermittent squeal or groan each time they contact the turning rotor. The noise goes away when you step on the brakes. Check the pad wear by pulling off a wheel and looking through the slot on the circumference of the caliper. You should have even wear on both pads, and at least an eighth of an inch of pad left. If not even you'll need to pull the caliper, and clean and lube the pins it slides on. If worn or uneven, replace them; it doesn't pay to try and wait for pads to wear down any farther, because you'll probably end up scoring the rotor.