Rotor wear after bearing replacement

[crunchie46]

My rotors wore evenly before i had my wheel bearings replaced at mississauga mazda. From all the driving i have done i know that the discs will form a layer of rust and after a few good brakes it will disappear. From the picture you can see that the rust is'nt going away on the whole disc. Mississauga mazda machined my discs and sanded down the pads but this is still happening but they say this is normal and it is because i have my calipers painted. Can someone tell me if this is normal because it seems to me that the pad does'nt have full contact with the disc.

http://i277.photobucket.com/albums/kk75/crunchie46/DSC006152222.jpg

[Donutz]

I believe you are right; the pad does not contact the entire face of the rotor.

[crunchie46]

So what should i tell the dealership?.. Is this really caused because of the caliper paint or are they just trying to get out of a major repair.

[McGuyver_3]

rotors rust easily anyways any slight water on the rotor will cause it to rust it is normal and in your case being machined already it causes them to rust even easier. The pad does not make complete contact with the rotor. that is just the way it is. Personally whenever i do breaks i ALWAYS replace pads and rotors machining them just makes it worse IMO

[crunchie46]

So in my situation should i be asking them to replace the pads and rotors or should i give up the fight. I figured the pad has to have complete contact with the rotor. Is it the caliper itself? What is preventing this from happenning if i replace both the pads and rotors?

[Flagrum_3]

So in my situation should i be asking them to replace the pads and rotors or should i give up the fight. I figured the pad has to have complete contact with the rotor. Is it the caliper itself? What is preventing this from happenning if i replace both the pads and rotors?

I think your misunderstanding what others are saying here!.By them saying the pads don't make 'complete contact with the rotors' they mean the full width of the pads are making complete contact with the rotors, but that the pads 'width' is smaller than the width of the rotors face!, therefore there are untouched areas! manly above and below the pad line
...This is "Normal" and you can see these lines clearly in your pic; the contact area on the rotor itself is clean and shiny where the pad touches....Understand that any untouched area will form a layer of rust.There is not much you can do to prevent this, except maybe by purchasing a High quality "Coated Rotor", even then it will still eventually rust!....otherwise you could pull the wheels off periodically and fine sand the rust off but it will just come back eventually.

It is no fault of the dealer bearing replacement or of the equipment itself....it is just simply normal!


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[crunchie46]

The thing is... the whole surface was in contact with the rotor before they replaced the bearing. The passenger side is still in contact with the whole rotor. Is this still considered normal. I will post pics of the other side shortly

[McGuyver_3]

No the pad was not at full contact with the rotor it just happen that it was not rusted at the time. It is 100% normal that you are seing rust in those areas. Like Flagrum 3 said there is nothing you can do to avoid this the rotors will start rusting as soon as they get moist. even my rotors are doing the same and i have replaced them already because they were due for replacement anyways.

[baymoe]

No, what crunchie is concerned about is that the rust pictured would usually be in contact with the brake pads, but it isn't after the "repair". He understands that there are sections of the rotor that does not contact the brake pads. I believe once the pad wears down a bit, it will make full contact.

[McGuyver_3]

This is what it looks like
http://i11.photobucket.com/albums/a190/bmw_racing/Untitled-2.jpg

[Flagrum_3]

Nice drawing Dan! :) ....But I think I understand more clearly here what crunchi is saying.Crunchie I'm guessing those are your front rotors in the picture? (hard to tell but I think I see fins and from the caliper position), If so I'm going to check my rotors to see how the contact area looks on mine for comparison....

After the brake service did you bed them in again with several stops from 60 and 80k, this may have been needed since they sanded the pads and turned the rotors...anyways shoot me an answer and I'm going to check mine out.


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[Noisy Crow]

Either the rotors were originally thicker at the point, or they are now thinner at that point.

[crunchie46]

Yes, they are my front rotors and i did do a few stops from 100km to see if it would do anything but its still the same. I will post pictures of both sides with a better camera after work today. The braking seems fine and there are no vibrations.

[McGuyver_3]

im still lost as to what you all are referring to the rust is normal and the pad does not make full contact with the rotor so what are we debating about lol????? :S

[Flagrum_3]

Dan, I believe he is talking about the rust on the bottom 1/4 inch or so of the contact area of the rotor, the pad should clean that area up as I just checked out my rotors and that area of the rotor is in contact with the pads.

Crunchie, take it back to whomever did the brake work and tell them to fix it, that is not normal!


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[crunchie46]

What should i tell them? The mechanic there said this is completely normal and it is because i have painted my calipers. I personally think thats bull****. He said the heat isnt allowed to escape. Should i go get a second opinion from somewhere before i go back?

[crunchie46]

Passenger side (normal wear)

http://i277.photobucket.com/albums/kk75/crunchie46/IMG_2461.jpg

Drivers side (problem)

http://i277.photobucket.com/albums/kk75/crunchie46/IMG_2460.jpg

Driver side closeup (problem)

http://i277.photobucket.com/albums/kk75/crunchie46/IMG_2463.jpg

[Flagrum_3]

On mine the pad covers the same area as your first pic (passenger side), so it looks like something is definitely askew on the other side and I would doubt it has anything to do with the calipers being painted or else it would be on both sides!! (ask them to explain that :chuckle)....they definitely screwed up something. (I would deduce that the guy screwed up when he machined that particular rotor, I can barely make out a line where it looks like he started making too deep a cut then raised the cutter)....can't be positive though from the pics!


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[kaval]

Take it to someone else, I bet the pad isn't mounted properly, or the actual pad that was installed isn't proper.

Having your calipers painted should not affect the way the pad makes contact with the rotor. If that was the case, you wouldn't see as many people painting their calipers in the first place.

[crunchie46]

I just went to another dealership and they said they think its normal but it was'nt a mechanic who looked at it. Does anyone know a trusted mechanic that can take a look at this for me in mississauga.

[mazda lover]

My rotors wore evenly before i had my wheel bearings replaced at mississauga mazda. From all the driving i have done i know that the discs will form a layer of rust and after a few good brakes it will disappear. From the picture you can see that the rust is'nt going away on the whole disc. Mississauga mazda machined my discs and sanded down the pads but this is still happening but they say this is normal and it is because i have my calipers painted. Can someone tell me if this is normal because it seems to me that the pad does'nt have full contact with the disc.

http://i277.photobucket.com/albums/kk75/crunchie46/DSC006152222.jpg


where the arrow is on thee pick my rotors are clean, no rust
2005 GT GFX 44,000KM