Is this normal?

I also hear this.

I'm thinking it's the brake calipers. This is just my guess but i'm thinking there is a little foward and backwards play in them and it only shows up when backing. mine sounds more like a click than a clunk.

 

Mine has done it from new and still does it with no ill effect. I'm at 46k miles now.

 

Mine does it also since it was new, as they say, don't worry bout it.

 

Mine does it too, but only in the morning after it's been parked all night (garage). I assumed it was moisture or road debris on the rotors/pads from day before. Also, after the Prius is washed and has sat for a while, the noise (grinding) is predominate for the first couple of brake pedal applications. I'm certain it's moisture and not a problem.

When I back out in the morning, the first thing I do is lightly apply the brakes to clean off the rotor. This also keeps the car from surging when the ICE kicks on.

 

It's normal...at least for the Prius.
Remember that when you're backing up, you're not using the engine (at first) and so you're more likely to hear and feel the brake shoes cleaning off the rotors, which will always have a little surface corrosion even after an overnight park. Also, 99+ percent of your braking is done while the car is moving forward. A reverse braking will cause the calipers and other pieces/parts to shift a little bit, which may account for the noise and/or pedal input that you're experiencing.
I'm not sure if this is exacerbated by the additional regen braking components---but suffice it to say that you don't have to worry about the noise........as long as the car is still stopping normally that is. You're at 13K miles. You're car is still covered by its warranty. If the noise really bothers you then you can take it to the dealership, but I think that they're just going to take it for a short hop (or tell you that they did) and give you more or less the same answer that we did.
Best of Luck!

 

So from what everyone is saying the answer to your question would be Yes. Now go out and enjoy your Prius and stop worrying !

 

My 1-month old Prius does the same thing every time I back off from garage in the morning. Thank for the info.

 

I had my car in today to have another rattle investigated, and mentioned the clunking on direction changes. My hybrid tech advised that it was due to the brake pads shifting around in the calipers and was normal. Mine gives off a hell of a clunk - probably more audible because of the lack of engine noise and reflected sound off of any nearby objects (adjacent car, wall, etc).

-Iain

 

Let me know how the rattle repair goes.