Brake Rotors - what causes this?

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Finally got around to taking off my snow tires and took a look at my rotors and saw the below.




What causes this? Rotors are about 2 years old, 6,000 miles.
 
Originally Posted By: Superflop
Road deicer


Ding Ding, we have a winner!

I'm only getting 3 or 4 years out of a set of rotors, and I remove my pads a reapply brake pad lube or my pads will seize in a couple years.
 
Salt/road deicer
They will not be able to be turned clean.
New rotors is what will fix it.
Try ebay
I got a few sets of pads and rotors off ebay a few years back
Callahan auto parts yup just like Tommy boy.
05 Pontiac vibe was like 60 for pads and a pair of rotors shipped.
08 gmc sierra was like 95 for pads and rotors.
They are fine only problem is the vibe is a little squeeky some times. But so were the wagner thermoquiets they replaced Looking back on it i should have just snagged the rotors for 42 and got the ac delco pads for 25
It did take 18 months and about 15000 miles for the brakes to squeek.
So if this is adventure you will be doing every 2 years or 6000 miles
The callahan rotors and pads would be a excellent choice.
Even though they are cheap they are of a decent quality.
The rotors are heavy and well constructed.
The pads were ceramic for both applications.
I have never felt that they were inferior in any way they stop very well.
 
Low quality rotors, metallurgy issue. But this is largely due to the road salt in your area. Try some rotors that come coated; it may delay the issue a bit.
 
Originally Posted By: 99Saturn
Finally got around to taking off my snow tires and took a look at my rotors and saw the below.




What causes this? Rotors are about 2 years old, 6,000 miles.



If you think that looks bad wait till you see the inside side of that rotor.

I live in the Minneapolis area and they salt the [censored] out of our roads, I also saw a lot of this when I owned a hobby Audi repair shop. First off 6,000 miles in 2 year also explains some of it. Looks like your car does a lot of sitting, that in turn means a lot of time to start oxidation. Just saying, you have I would bet 50 to 60% less braking power because of reduced "swept area", you are a danger on the road. When it rains, I always take the car out for a 4 minute ride of heavy braking to clear the rust of from the rain if I know the car will not be use within 1 1/2 days. IE weekends since my car is use as a work car and we use my wife's car more on weekend.

When My Honda was recalled with the airbag recall I was given a loaner car from Honda and was able to park my carin my garage for 3 months will waiting for new airbags. I signed a paper that I was not going to drive it and if I did they were not liable. I did drive my car around the block every 2 weeks to clear the fine rust that was starting.

Ways to reduce this when you get your new brakes:

1) Don't let rust even start after a rain, drive the car with some heavy braking.

2) Become a heavy braker, use them or lose them.

3) Buy coated brake rotors so rust that can start on the outer edge has a harder time migrating inward.

IE EBC brakes or others of the same.(can be electro plated too) http://www.autoanything.com/brakes/ebc-brake-kits

4) Don't let rust even start after a rain, drive the car with some heavy braking.
 
lack of driving in the rust belt is what causes that. The only real way to prevent this is to drive the car more to keep the rust from getting too deep and abrasive.

once it starts, it cant be reversed without machining the rotors or replacing
 
Lack of use plus rust nets what you are seeing. If you drove it more regularly it would help with keeping the swept surface clean and not corroded. Higher end rotors may help, emphasis on the may...
 
Salt and non-coated rotors
crazy2.gif


Get new rotors that are coated. Something like Wagner E-shield or Centric Premium.

You may need new calipers, too. Again, use coated calipers like Napa Eclipse or Cardone Ultra.

Are the pads showing a tapered wear pattern?
 
Originally Posted By: Mainia





Just saying, you have I would bet 50 to 60% less braking power because of reduced "swept area", you are a danger on the road.





OP, you could and probably should test this. Do some emergency stops at varying speeds. If you can still lock the wheels up then your brakes are as good as they need to be, whatever the notional capacity loss.

I'm not entirely convinced corrosion is all that's going on here. Contact looks uneven and is concentrated towards the centre of the disk. I've heard of corrosion undercutting disks from the outside-in but thats a pretty extreme example.

You might try this, either on those, and/or on whatever you replace them with, along with more aggressive braking.

https://www.bobistheoilguy.com/forums/ub...sks#Post3830294
https://www.bobistheoilguy.com/forums/ub...ums#Post3864753

I havn't tried it on the actual face of the disks but on those ones I probably would (without using any binder), since you dont have much to lose.
 
Last edited:
Correction: That should be "I've heard of corrosion undercutting pads from the outside-in but thats a pretty extreme example."
 
It's mainly due to not driving.

Last year I let my car sit for a few weeks and the brakes looked/worked like [censored] afterwards. The rotor surface was even before parking, but afterwards I was starting to see uneven rotor wear.

Better quality coated rotors will help slow it down.
 
You could also find pads that are "harder" on rotors. Hawk racing comes to mind. These are shot, but I'm thinking prophylactically. Had this happen on my incoming s-series beaters as well.
 
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