I recently just replaced all the brake pads on all 4 wheels on my maxima. I pushed calipers back using a caliper tool I got from harber freight. I then bled the brake lines out, turned my car on to pump the brake pedal and all was good until a couple hours later while I was driving the brake light came back on. I pop the hood and my brake fluid is completely empty! It's a rapid leak because I had topped off the fluid when I replaced the pads. What's most likely cause?

 

When doing work to your brakes, did you let the calipers hang by the brake hose? If so, this probably exhausted the wear on your brake line and caused a leak. If it is a hose, then don't get too worried about it. Brake hose lines are very cheap and the labor for 1 hose should be no more than 1 hour worth of labor, probably even less, I paid 50.

 

Look at each caliper, you'll see which one is leaking. Rebuild or replace the leaking component.

 

did you forget to tighten up one of the bleeders?

why did you even bleed the brakes anyway if you were just changing pads?