Prius (Gen 2) :: No Resistance In The Pedal - Brake Turned To Back Out

I was waiting for my son to come out of his work for an hour with the car on. I got distracted reading and messing around on my phone, and since the heater and lights were off, I had no incentive to turn the car off since it was perfectly quiet (the gas motor only kicked on once to keep the battery charged). Then, I can't remember if I turned the car off or left it on while I took a nap for an hour (he was a total of two hours late getting out of work).

At any rate, when he finally came out, I don't remember if I needed to turn the car on, but I do remember that as I pushed the brake down, put it in reverse, and began to back out, I was moving kind of fast and pushing the brake down didn't slow my motion at all. Also, it felt like there was not much resistance in the pedal. I stood on the brake and there was a noise and a jolt as I came to a stop. I really thought I had stopped because I hit something, that's how violent the stop was. But my son walked around the car and found I had not. No dash warning lights came on. I pushed the park button, powered the car off and on, then put it in drive and coasted forward / carefully tested the brakes. All was good.

I put it in reverse and used the brakes without anything seeming out of the ordinary. Then we drove 16 miles home with no issues. Until this incident I have never had a single brake-related issue apart from grabby brakes when it is raining.

This is what I have learned:

When I stood on the brakes, that is the only time the hydraulic system was in play.

Rusty brake components are pretty grabby.

Actuators are expensive and no service center wants to replace them at 92K miles.