I've had a very slow brake fluid leak for over a year. adding fluid every 3-4 months but I couldn't figure out where the leak was coming from. It seems to have sped up recently - how do I find it? Is this go catastrophic and stomp on the brakes until something pops? I noticed it is really pretty ugly by the rear brakes, like old school rust but didn't see any weeping when I last checked...
I want to address this straight away but if they go, will I lose fronts and rears b ut will still have E-brake?

 

have you changed out your pads
or checked to see if there getting down to the metal

when your pads start to where out
your fluid will go down as well

if you check your pads and see that they need replacing
change them out and then see how much brake fluid you still have ^_-

 

You want to address a long time issue that has been going on? I'm sure that sucker is leaking somewhere if you have to top off the brake fluid. You're probably not even trying to fix the problem. If you're having rust issues than you need to inspect all brake lines, calipers, and drums.

 

Sounds like the rear wheel cylinders are leaking.