Brake question
 

My workman's truck has been losing brake fluid since this morning. We crawled around under there to see where the fluid is leaking from. Nothing, everything is bone dry. No traces of anything at or anywhere around the wheels. Nothing under the hood near the brake booster. Could it be somewhere in the brake lines? It stops like normal as long as the reservoir is filled with fluid. He's already filled it up twice today and they are all gone again and no wetness on the floor. Its a Toyota Tundra, 06-08(I think?). What do you gents think?

Brake fluid leaking out of the back of the MC into the booster? Not enough in the booster yet to be leaking out?

Or into the bell housing. (? - some are sealed )

+1 to the mc. Check around pedal for damp carpet...

Thanks guys. Will take a look tomorrow

The MC is leaking into the booster and the fluid is being sucked into the intake manifold. You don't see it because you're burning it.

That's my guess...white smoke, I think?

Pull the vacuum line off and see if it has brake fluid in it.

My guess is also this. Had it happened to me in an old Chevy Impala.