re: Have you ever lost the brakes on a vehicle while driving?

Yes. In Little Rock. Thankfully I go in early, the roads were empty, and I made my way to a shop near my office.

Yes. Many years ago in a 1995 Buick Bonneville. Brake line busted and the brake pedal went to the floor. Was out of town for a kid's baseball tournament and on the way to the first game in the morning. Just happened to be a GM dealership a few blocks down and on the right. Immediately coasted it into the lot and had it fixed.

It is an extremely helpless feeling to have no brakes.

Yep.. had it happen once on a cargo van. Got lucky and was able to coast in safely, no injuries or other damage. The brakes still had a little catch left at full pressure, then engaged the parking brake. Had to tow it to a shop from there.

Three times

First Rental Car in Michigan on the way to return it. Great timing

Second. Rental car in Canada. We'd had it for a trip around Newfoundland, got on and off the ferry back to Nova Scotia and about five miles in, breaks got wretched mushy. Low traffic so went to rental car place at the airport and returned it with warnings and got a car with breaks.

Third. My Pontiac, had the breaks replace, took car to Hobby where it sat for two days. Driving out of the parking garage 9second story), breaks turned mushy. Late night, drove car home, parked on the street in front of my house (about a half an hour after midnight.)
Next morning got a co-worker to give me a ride.
Called the business that had done the breaks, told them the problem, told them where the car was, where I'd put a spare key, and that I would pick it up after work that afternoon. And I did.

My brother lost the brakes while backing a boat down a very steep boat launch using an 1950s vintage Ford tractor with a grade blade and front end loader. We used it because vehicles generally could not maintain traction on it while hitched to a trailer.

A witness told me that as it gained speed he tried everything to stop it. The last gasp was he dropped the grader blade, and as the tractor bucked up and rode over the blade, he jumped to clear it and rolled out of the way.

It was quite a sight to see after the fact. He didn’t have a scratch.

When I was young and dumber I once waited so long on changing my brake pads that I threw one and was grinding metal on metal. Learned a good lesson on why maintanence is cheaper than repair with that one.

Yes, a 1976 Camaro. My first car, bought it used for $3400. Fortunately I was just backing out of the driveway when the brake pedal went straight to the floor. The dual exhaust had been modified by the previous owner and one of the exhaust pipes was slightly rubbing against a brake line, and it eventually wore a hole in the brake line.

If you ever own a Willys vehicle, it will happen at the worst times. You will learn to rebuild wheel cylinders and bleed brakes alone anywhere.

Had an old truck in high school. Was skipping class just riding around. The person in front of me hit their brakes and I hit mine. Pedal went to the floor and I drove into ditch and around the car.

Drove to school and had to tow the truck home. Lucky to say the least.