i have a 280zx with two resevoirs. the front one (back brakes) losses fluid once a week. i thought i fixed the problem by buying a new master cylinder( the old one was leaking) it went prob 3 months and now leaks again. going once a week. i check the fluid levels and its almost all gone. i park in the drive way and check the rear brakes and no leaks anywhere at the caliper. what could the problem be?

 

Put it up in the air & inspect the calipers. Just because there isn't a puddle on the ground doesn't mean they aren't leaking. Also inspect the brake lines.

 

ill follow the lines tommorow, last time i checked the calipers were completley dry, so ill start from the front to the back