This has occurred several times while reversing out of a parking space. Basically, I've been parked at a store for a short while (less than 15 minutes). However, when I back the 2007 Prius out, 1) the brakes don't catch initially and 2) the car stops so abruptly I'm certain that I've hit something (or someone). This entire sequence occurs within a few feet of starting the car and backing out. Today I backed out a parking spot, car stopped like I hit something; I then got out of the car because I expected that I had run over someone's body...neither person nor object were there though. What I do (and have always done/no issues) but now with unexpected results: 1. get in car and apply the brake with foot 2. start car and put in reverse 3. release the brake and reverse but the car now "rolls" without any tension from the brake being released 4. as soon as I realize I'm rolling, I panic and reapply the brake 5. car abruptly stops (to the point of shuddering stop) 6. then drive away is fine Checked the brake fluid and last time my tires were inspected about 3 months ago they told me my front brakes were still good/had life in them. Is this an indicator of the brake actuator going bad (car has 340,000 miles)? Thoughts?
And no lights or anything on the dash interesting I guess first I would bleed the brakes or just see what happens when I crack the screws or the fittings one at a time starting with the right rear do you have fluid dripping when you crack the fitting let it sit there and drip a minute does it ever stop or slow down yeah I know. Now see if the car still does it
UPDATE: I just noticed the lack of braking ability as I tried to stop going forward at a slow speed. Its like (similar to in reverse) the brakes too a few feet to "catch". gonna look at my brakes/lines over the weekend. might be as simple as the front pads going bad.
I get that on my gen3, occasionally. First time it happened I was backing up in prep to leave a parallel parking spot. I touched the brakes and the stop was so abrupt I thought I'd misjudged, backed into the car behind. No clue what causes it, always happens when just starting up, in reverse. And just every so often, not an everday thing.
If the OP's car does this consistently... Start the car. Wait 30 seconds (just a guess, 10 seconds might be enough) Pump the brakes a few times. Do the brakes now work normally the first time? It kind of sounds like brake fluid pressure is low initially (so the brakes work poorly) and then after a few seconds it returns to normal, but the brakes are next applied hard so the car slams to a stop. If the car is given some time to warm up, and the brakes pumped proactively, the "low fluid pressure" phase may go away. That said, the brakes shouldn't ever do that. It could be that the part of the ABS system which hold pressure has a leak, so after the car has sat for a while the expected stored pressure isn't there, it only comes back after the pump has run for a while.
I had that happen consistently for a while. My ABS lights came on as well later. I also had the intermittent whirring that sounded like something was winding or cranking. I ended up getting my ABS diagnosed as bad and replaced it with a new one.
