Spongy pedal; leaking master cylinder sensor... Ideas ?
 

Hi folks !

I bought a 1994 Corvette almost a year ago, drove it for around 1500 miles without any problem.
The previous owner told me that one sensor at the master cylinder was leaking but just a bit, so he added brake liquid when needed. So did I.
I noticed last month that the pedal was a bit spongy, took it for a drive then disappeared.
I maybe drove 200 miles then , yesterday, I just wanted to move the car in the garage and found a spongy pedal that went all the way down with very poor brakes that could hardly stop the car...

I pressed the pedal about 10 times and it was hard again. I took it for a 30 miles drive, no problem.

Here are pictures of the sensor I'm talking about. it's not between the white plastic part and the metal of the master cylinder that it's leaking but seems to be between the white and black plastics, or at the rear of the black plastic as the metal wire can be seen.

What are your advices ?

Assuming that the fluid level is good, probably need a new master cylinder. What's the sensor for, fluid level?

I have a similar situation. Have firm pedal after bleed, then pedal become spongy and goes almost to floor. I have replaced: new power diaphram, new master cyl. [bench bled], new rubber hoses to calipers, new calipers, new pads, new rotors, Bled brakes wit both a hand vac pump and with assistant in vehicle pumping brake pedal. I get a good firm pedal with engine off. Start car and put in gear to move and pedal gets soft. Brakes stop car on road but take extra power to push pedal hard enough to stop. ASR and ABS light come on. Got code from drivers information center and cleared codes, lights went out but pedal is still soft with engine running. any body have any more suggestions? This is a 1994 Corvette base coupe.

Welcome to the forum. Can't think of anything to suggest but I suspect something to do w/ the PB booster.