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What would cause brake rotors to do this on both rear brakes on a 2001 Honda Accord. Usually you can find about anything on the Internet as well as pictures of a specific problem, but I could not find the answer to this or a picture of a similar problem. Why would a “layer” of rotor metal basically fall off like this on two rotors (see picture) Note that this is not normal rust. This is an even layer of metal coming off. Two things that I do know is that these are not Honda OEM rotors since they did not have the painted hat and the calipers were not dragging on either side.
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How old are they?? They look like they have been sitting around for a few years and not used. I’ve always seen that happen to metal in a junkyard.
These were NOT sitting around off the car just rusting away. We bought the car used with 86,000 miles on it and these were on the car installed as you see them. The outside of both rotors were badly scored and were the worse I had ever seen on a car, but the “layers” of metal were only coming off on the inside of both rear rotors. When I got the car there was no metal to metal contact between the pads and the rotors or when we found the rotors looking like this. Keep in mind that when metal rusts it does not come off in nice neat layers like this. Are rotors made up of different layers of metal and one layer is coming off? The funny part is that the “feel” of the brakes was not as bad as you would think it would be with a 1/32 inch or slightly more layer of metal missing! Here is the other rear rotor.
I believe that layer is due to a combination of rust and pad material that has fused together due to heat from the application of the brakes.
It looks like the pads were touching only on the inner half of the rotors, the shiny part. The parts that flaked off seem to be on the outer, untouched by the pads areas. Those areas will get very rusty, as they heat up due to the normal brake action, and they get wet in the rain, and those areas don’t get scrubbed off and smoothed out by the pads. You can expect the rust to fall off like that.
Rotors are made from cast iron and then machined to a flat surface. The material should be the same all the way through.
This usually happens when the brakes get too hot or are heated then cooled heated then cooled over and over again. I’ve seen it on a lot of my hoon customers’ cars
I sure thought it looked pretty bad. Wonder what caused the overheating. As I mentioned earlier, the calipers did not appear to be dragging at all. Maybe the first owner did this with the parking brake left on. The shape of the missing metal does appear to be similar to the shape of a brake pad. We replaced the pads with Honda OEM pads and Brembo rotors and have not had any problems yet in about 10,000 miles of driving, but I was wondering about what did this.
The parking brake in itself is a seperate system. So it wouldn’t have caused that.
It looks to me the caliper wasn’t functioning properly. You may have a defective piston. The only cause to that is simply part of the the pads never made contact with the outside of that rotor, causing it to rust. if it did make contact, it wouldnt look like that. I can tell you just by looking at that picture. Rotors are cast iron and should never flake like that. Its possible the rotor went through enough differential stress, and if it wasn’t tempered correctly after the casting process you’d see what your looking at over a period of years.Check out the pads/ rotors you recently installed and make sure the rotor material is wearing away evenly, and check the pads for uneven wear. Check your bleeder valve by cracking it open, and compressing the piston. If nasty black gunk spits out you need to bleed your system. If you see a trickle come out then you have a blockage in whatever caliper your testing (it should shoot out with decent force), which could also lead to uneven wear.
I’ve actually seen this a few times. The main cause is lack of brake service. Honda uses some pretty crappy rear calipers in my opinion and if you don’t get in there and service them about ever 30K or so they start to hang up. Once they do they make more heat. More heat = more wear on the brake parts and more metal fatigue for the rotors. It’s also quite common for the rear pads to rust into place inside the caliper. I normally deal with this by grinding the pad bosses down a little so that they move freely inside the caliper. This mostly happens on the inside pad BTW.
So, don’t worry, I’ve seen it before and it’s not unusual. I would however advise regular brake service and quality brake pads to avoid the issue in the future.
[quote=”EricTheCarGuy” post=87567]I’ve actually seen this a few times. The main cause is lack of brake service. Honda uses some pretty crappy rear calipers in my opinion and if you don’t get in there and service them about ever 30K or so they start to hang up. Once they do they make more heat. More heat = more wear on the brake parts and more metal fatigue for the rotors. It’s also quite common for the rear pads to rust into place inside the caliper. I normally deal with this by grinding the pad bosses down a little so that they move freely inside the caliper. This mostly happens on the inside pad BTW.
So, don’t worry, I’ve seen it before and it’s not unusual. I would however advise regular brake service and quality brake pads to avoid the issue in the future.
https://www.youtube.com/watch?v=cKpmBvfVYZg%5B/quote%5D
That’s rather interesting and good to hear.. Something I’ll keep a note of when I service Honda’s.
On a side note I too have made a habit of using a griding wheel to grind down the ears on front pads whenever I deal with Lexus/ Toyota, as they have a tendency to stick over time as well.
Good tip, thanks Eric.That is not metal that fell off but rust buildup that has flaked off of the rotor. I see this a lot on vehicles that do not get used and on vehicles where the brakes have stopped working.
[quote=”Just1Tech” post=87570][quote=”EricTheCarGuy” post=87567]I’ve actually seen this a few times. The main cause is lack of brake service. Honda uses some pretty crappy rear calipers in my opinion and if you don’t get in there and service them about ever 30K or so they start to hang up. Once they do they make more heat. More heat = more wear on the brake parts and more metal fatigue for the rotors. It’s also quite common for the rear pads to rust into place inside the caliper. I normally deal with this by grinding the pad bosses down a little so that they move freely inside the caliper. This mostly happens on the inside pad BTW.
So, don’t worry, I’ve seen it before and it’s not unusual. I would however advise regular brake service and quality brake pads to avoid the issue in the future.
https://www.youtube.com/watch?v=cKpmBvfVYZg%5B/quote%5D
That’s rather interesting and good to hear.. Something I’ll keep a note of when I service Honda’s.
On a side note I too have made a habit of using a griding wheel to grind down the ears on front pads whenever I deal with Lexus/ Toyota, as they have a tendency to stick over time as well.
Good tip, thanks Eric.[/quote]The calipers for those vehicles are also made by the same manufacturer that makes them for Honda. 🙂
Hello Eric,
I see you were actually looking at my pictures and questions and provided some input. The funny part is that I was just watching your video on doing the rear brakes on a Honda Accord five minutes ago. I guess it would have make more sense for me to have watched your video before we did the rear brakes. I couldn’t believe how bad these rotors looked and hopefully when my son and I worked on them we got the calipers cleaned up enough that we don’t have any more problems. We put the Molykote 77 packet that Honda provides you with their pads on all the places the manual says. The metal missing off the rotor was one thing, but 1/2 of the pad was not even touching the rotor. The outside of the new rotors look like they are wearing ok and it has been about 10,000 miles, but I have not pulled the rotors off to inspect the insides of the rear rotors. After watching your video I was wondering if the “bump” that is on the back side of the pads might have not been in the piston slot properly and could have caused some of the problems since we just pulled the pads out and did not look to see if they were in right before we started the brake job.
What happens is that the rust builds up under the stainless shims in the caliper bracket. As this happens it decreases the clearance for the pads to move in. After a while, they just get stuck and you get what you found. I often grind the ends of the pads down a little on each side of the metal boss to make them move in the caliper easier and prevent that problem from happening again.
They look like normal, rusted, worn out rotors especially if you live where salt and Calcium Chloride is used on the roads in the winter. A lack of service contributed to the problem also. Seized slide pins and pads that can’t move in the brackets.
I see em like that and worse almost every day here in Canada.
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