Chevy S10 Complete Brake Failure

This morning I drove thru some standing water on the street near me. The water was axle deep.

When I came to the next intersection and stepped on the brakes, not much happened at first (no surprise). But as the brakes dried off, they came on.

Suddenly the pedal went to the floor - and I had NO brakes at all. I managed to get it home and parked it. I have not had a chance to look at it yet, but both master cylinder reservoirs are full - and the brake lite is not on.

I have never lost brakes on all 4 wheels before on any vehicle in my life. This is an OLD truck ('85), so anything is possible.

I’m thinking that there is a problem in the linkage between the brake pedal and master cylinder? Or…???

Thoughts anyone?

My guess is that the master cylinder is shot. You’re pushing the pedal, but the internal piston seal is blown and the piston isn’t compressing the fluid.

This may have happened bacause the MC was already on its way out and it your sudden crisis, fueled by adrenalin, you overpowered the tired old seal and maybe even pushed it into regions in the chamber where it doesn’t normally venture. It would have given out soon anyway, it’s just a blessing that it happened now and not when some youngster ran out from between two parked vehicles in front of you.