Scion brake problems

[F22Chris]

Car is an '05 Scion xB. The brake pedal gets super stiff when pumped and the car is off. Then, after it starts, the pedal goes almost to the floor. The brakes still work, no pumping needed to stay stopped so I don't think it's the master, but it should still not do this.

I replaced the front brakes and rotors. The rotors had some lateral run out, and the pads were shitty semi-metallic ones.

The pedal feel is better, but still goes almost to the floor. I'm going to replace the rear shoes, and bleed everything nicely as there's a bit of carbon in the fluid. There are no leaks as the fluid stays level.

I've been reading all over the Scion forums, and there are no answers. Well, none that are useful. So in the event that shoe replacement and extensive bleeding aren't fixes, what would you guys suggest?

Also, I'm only replacing the shoes as the car has 150k and they've never been changed.

[illinois_erik]

black stuff is the bundy tubing disintegrating from the inside out.. means water is in the system, flush it completely from each wheel either with some new fluid (like one complete bargain bottle for the whole procedure), or first with denatured alcohol then wait a bit for it to evaporate then fill and bleed. could be the brake booster dying, usually all cars will get a super hard pedal when its off with multiple pumps, maybe throw a vac gauge on it, pull a vacuum and see if it leaks down

[F22Chris]

Thank you Erik. I'll bleed completely once the shoes get here. I'll get on ProDemand and see what Mercury the booster has to be at. I just don't want my inlaws driving on sketchy brakes, you know?

Edit: this gives me a chance to test out my pressure bleeder. I'm excited.

[F22Chris]

So I bled out a quart and a half getting the contaminated fluid out, and the pedal still sinks. I'm going to replace the master. The booster holds vacuum, and the pedal isn't mad hard or anything so I can rule that out. I'm pretty sure that the nasty ass fluid in there before caused the master piston seals to swell. Damn water; I don't think they ever hanged the fluid on it.

Shit was mad gross.

[F22Chris]

Got the master replaced. Gonna take it to ATL Custom Creations to get it bled. Hopefully this'll be the end of this.

I had a thunk when braking, took the pads off and saw literal chunks missing from the pads. Bullshit.. Be cautious if you have a 1st gen and get ceramics with the part number 1249.

[Raf99]

Did you bench bleed the MC?
Does your power booster pass pedal tests?

I'm going to say its the power booster. Especially if there is pedal travel before the brakes start working.

[F22Chris]

Second master was bad. Replaced with a new one. Bench bled the shit out of it, and gave the brakes a quick bleed. Brakes work great now.

Yes I did pedal tests, and bled soooo much fluid. Also adjusted the drums so it takes 2 clicks on the parking lever instead of 20. Now I just have to replace the driver side pads for the 3rd time because they cracked again. Too much heat from the pedal on the floor I guess. Regardless the brakes work and don't drop.