My prius gen 2 makes quite a loud grinding sound when braking to a complete stop. It only happens during last few moments of braking from a crawl to a stop and doesnt happen when braking at any other speeds ( for example from 30mph to 20mph or 20mph to 5mph is all fine etc ) the sound feels like its the brake pads slipping over the discs at the last moment before a complete stop. im not sure if its because the brake pads need replacing or if the HV battery is not cutting out at the correct timing. had car fully serviced at Toyota in july and they reported back pads 4mm left, front pads 7mm left, Do the brake pads need replacing or is it something else causing the issue? Just to confirm there is no actual functional problem, the car brakes fine and doesnt judder or jerk when breaking, it is purely only making a loud sound, which is concerning. 75k miles on the clock and I dont know anything about service history
there is a low brake pad warning sound. otoh, maybe something is just caught in there. why not have a look at them?
You are saying it is noisy only the last moments of stopping. Thats is because before those moments the prius doesnt stop with the conventional brakes but uses it's hybrid system. Normally those brakes last 2-4 times more than any normal car. Some of them last 200k miles. I replaced mine on 150 and they were provably same thickness as yours. I also had some grinding noise. Normally any friction would make noise but if it is like you say louder...then it oculd be few things. On my car I found that the passenger sidd slider pins were rusty and coroded so it affected the caliper performance. Have those pads and shims replaced. They are inexpensive and not necessary needed to be from the dealer. And are easy to do. The fact toyota inspected the car doesnt mean that those brakes couldnt fail the moment you got out the door.
Now with so many people buying used g2s we are going over the same things the car does when it was new. If your car lives outside it will get a fine layer of rust on the front brake rotors from dew. This rust is causing the screeching and crunching. If the car not driven for a few days that sound gets really bad. Very well known issue with this car. The fix is to clean the rotors. Find a nice empty stretch of highway get the car up to 60-70 miles and hour then put the transmission in neutral which defeats the regen braking assist. Then you are only on the very poor hydraulic brakes. Apply the brakes very firmly and pull the car down to like 40 miles an hour. Repeat. Then put it in d and drive away. That removes the rust. Don’t be freaked out how poor the brakes are. There very weak without regen, But if this has never been performed you may find the rotors might be pretty scored. Look through the front wheel spokes closely with a flashlight. The rotor surface should look like a mirror with no gouged lines Or rust. If the rotors look bad the smallest amount of rust will cause great screeching. A garaged g2 will not have this issue. You can mitigate this with a stored outside g2 with Vinyl wheel covers. A regular car does not have this issue as the very strong regular hydraulic brakes are in constant use So always great pressure of the brake disc on the rotor so always continued cleaning of the rotor. Compare your rotor condition to any other car and you’ll see what I mean.
I do a bit of rotor cleaning often (pretty much any morning if it has been damp out overnight), but I have never needed to make that much of a production out of it. There are three stop signs on the way out of my neighborhood. In between, I maybe hit 28 mph. I just shift to N and make an ordinary stop at the sign. By the second or third stop sign the brakes are quiet. If I have a passenger, they usually don't even notice I did anything unusual. I just do it any time I hear that familiar rough-brake sound as I'm pulling out of the driveway.... -Chap
First time it needs to be done takes a little more pressure. After that it can be maintained at a lower speed.
