2002 ford Taurus. e brake light on dash stays on. removed, checked e brake pedal switch with volt / ohm meter and it works. found and pulled the fluid sensor under master cylinder. pulled pigtail, light went out. I ordered the sensor, installed it and light is back on. I found a very very slight leak in wheel cylinder in right rear drum drum brake. replaced, bled, light still on. only symptom is that the brake pedal, while applying constant, medium to heavy pressure, 'creeps down' noticeably but slowly, but doesn't reach the floor.
there are no leaks anywhere and fluid level is good.
Question one: can that sensor sense problems within the master cylinder itself, i.e., some sort of bleeding back when brake is applied? If so I'll probably just bite the bullet and install a master cylinder.
Question two: is that sensor reading something like a float inside the fluid reservoir? could the float(s) in there be defective, i.e., sinking causing a false read by the sensor?
Question three: can you take the reservoir off of the master cylinder without removing the cylinder itself? I'd really like to do that to see wtf that sensor is reading. seems impossible that a plastic stick under a plastic tub can read fluid levels like that.
Question four: one of the rotors has a little scoring but nothing deep; brakes don't pull at all and pads have >> 50% left. can sensor read some sort of differential level in the master cylinder reservoir?
Question five: anybody know how to check the sensor - maybe the new one is defective?
I think I'll check the pads / rotors, bleed everything again, and replace the master cylinder if that doesn't work.
Any help or insight in diagnosing this would be appreciated. thank you