2010 Prius rear brakes need replacing after 25k miles

I feel like sharing my experience with needing my rear brake pads being replaced on my 2010 Prius. I understanding this forum is mainly for discussing self-driving cars, and in another post I’ll explain why I’m going to trade in my Prius for a Subaru with Eyesight. But for here, I’ll explain a potential issue with the Generation 3 Toyota Prius.

First off, I love my Prius. It has been exceptionally reliable and gets fantastic gas mileage – typically more than 50 mpg. I hate car dealerships though as I never trust them. I do a lot of driving, which is why it is nice to get great gas mileage.

At my 90k mile service, they said my rear brakes need new pads. I had heard that the Prius brakes generally last a really long time because usually the regenerative breaking is used to stop the car. Looking things up, it seemed other Prius owners had to replace brake pads at around 90k, so I didn’t think much of it. My front brakes still had decent wear left. My dealership charged my around $200 to replace the pads. It took them a lot longer to get the work done, which was annoying because I had to be somewhere that night and was late because of the slow work.

After the pads were replaced, it seemed my mileage was not as good as I had been used to. Also, when stopping, I frequently heard a grinding noise as I was coming to a stop. I was pretty sure they messed something up when they re-did my brakes. I took it in to the dealership, and they said they didn’t see anything wrong and they couldn’t reproduce the sound. Typical.

A few thousand miles later, the grinding was more frequent. I took the car back in, and this time they heard it. They said that there was a problem and that it could have been caused by me making several hard stops, but they went ahead and fixed it, having to grind the rotors in the process. I was never clear on exactly what they had to fix, but the noise was gone after that.

At my 110k mile service, they said that the rear brakes were in very good condition, and the front brakes are close to needing replacement. They said I’d probably need to replace the front brakes at 120k. My mileage seemed to return to normal after this.

As I’m approaching 115k miles, I start hearing a squealing noise when driving at slow speeds – when I’m NOT hitting the brakes. Standing outside the car while someone else was driving it and I could clearly tell it was coming from my rear right wheel. My gas mileage still seems pretty typical – when the weather is nice I get around 55 mpg according to the car (which is typically about 3mpg off)

I brought my car in for the 115k mile service, which is really just a tire rotation and multipoint inspection and tell them about the brake noise. I’m bringing the car in during my lunch hour, but figure it should be pretty quick. The guy tells me the service should be done in about an hour, but allow up to an hour and twenty minutes. Not ideal, but I figure it shouldn’t take the full time.

After about 45 minutes, I got to see the status of the service. I see my car still sitting in the spot where I pulled it in when I first got there. I’m a bit irritated, but the guy insists they already did the tire rotation, but it is a different team which needs to see what the problem is with the squealing noise. This makes no sense to me, since they will probably need to take the wheels off to check the brakes, and they can easily rotate the tires then, but what can I do? I tell him that I absolutely have to leave in 40 minutes. As he is telling me this, I see they come and take my car back. After another 30 minutes, I ask him what is going on and say I need to leave to return to work. He says they just found the issue and he needs to take me back and show me. I said that I hope they at least have the tires on because I have to leave soon. He is doing some paperwork for other cars while I’m standing there waiting, for about 10 minutes. Meanwhile, I see the other service staff sitting at their desks – one playing on his cell phone and another browsing the web looking at houses. I finally ask him what is going on since I really need to leave. He said he is waiting to see what the cost for the repairs will be and whether they can get me a loaner car. I’m pretty angry at this point and I ask can he just tell me what is wrong and what needs to be done. I said I really need to go and he then takes me back. Of course, the tires are off and I’m more irritated at this point, so I’m not really hearing all of what he says. I think what he said is that there is a part of the caliper (or near the caliper) that sometimes gets stuck due to the snow and salt used on the roads in our cold weather area. He said that it caused the pads to wear down and now the rotor also needs to be replaced. He said he is still waiting to see what the price will be and whether they can get a loaner. I said that they will have to do it another time, but unless they are going to pay for it since I just paid to have the pads replaced 25k miles before, I’m not going to have them do it again and I’ll take it elsewhere. I had never heard of Prius brakes going out anywhere near 25k miles so I’m thinking they must have messed something up when they redid the brakes at 90k miles. It takes another 15 minutes for them to get the car ready, and he tells me that he doesn’t see them paying for the repairs. I said that I need the bill for the tire rotation so I can go pay. He’s again taking his time with some other paperwork and I said I will go pay and he can do the paperwork later. He leaves and comes back with my keys and said they won’t be charging me for the tire rotation and I can take the car. He never bothered to tell me what the cost would be for the work they were suggesting.

The next day, I take the car to a local mechanic who has a good reputation. He looked at it and said that the pads are almost metal on metal, but that the rotors don’t need to be replaced. He does the brake job for just over $200. I asked him why the brakes failed after only 25k miles and he said that the calipers had not been properly maintained.

Looking on priuschat forum, I found a few threads with similar issues on the Generation III (3) Prius. It seems that they changed the rear brakes from Gen 2 to Gen 3 and the new rear brakes may be prone to this problem in snowy regions where salt is used. Because the car typically brakes with regenerative braking, the physical brakes don’t get much use and rust can accumulate causing problems. There also could be problems with the caliper slide pins which maybe is what they thought my issue was. Here are a few of the threads discussing similar problems:

Prius rear brakes worn after 55k miles

Prius rear brakes gone in two months

The general conclusion seems to be that the brakes do need to be serviced periodically to make sure that the caliper pins are properly lubricated and sliding.

On the plus side, I called Toyota Corporate to inform them of my issue. They were super nice and asked what I was hoping to gain by contacting them. I said that I felt I shouldn’t be responsible for the cost of the repair since I had Toyota regularly service my vehicle and they had just inspected my brakes 5k mile previously and everything was fine. I called on a Thursday and the Toyota service center called me back on Monday to say they will take care of the repairs and I can bring the car in whenever it is convenient. I told them I already was having the repairs done locally. They said they will send out a check for the repair cost which I should receive soon.