chsmith112

Midas told me that there was a burn spot or something like that on my front rotors? He said if the rotor and pad don't get "cut" or something like that it will get worse and eventually will need new rotors. He said somethin about how they were changed the last time is what caused it. I dunno what he is talking about........anyone heard of this and is it even true?

If it is true I will probably just wait and see how bad they get and then replace them with aftermarket rotors. Does anyone know what is the biggest and best rotor I can put under the OEM wheel? I was thinkin Baer. but im not sure.

cclive

If you don't feel a pulsing in the pedal when you apply the brakes, then there is no reason to 'cut' or turn the rotors. There really isn't any such thing as a 'hot spot' when it comes to brake rotors, that I have ever heard of anyway...

chsmith112

Ok I don't feel anythin in the rotor when breaking. It's pretty smooth. I don't know if he said hot spot or burn spot or something like that.

BC427

I have to ask. Why are you at Midas? Cheap pads. Cheap rotors. Questionable labor.
Rotors can develop hard spots. The rotor is a big heat sink. Heat is put into the rotor from the pads. The rotor is then cooled by the surrounding air and by the design of the rotor. If more heat is introduced than the rotor is capable of handling hard spots can occur. Cutting or turning the rotor will not solve the problem. Hard spots tend to develop completely through the rotor. Replacing them is the only cure. If left unchecked the pedal pulsations will become more violent.

Michrider

Dogs get hot spots. If your rotors are above minimum thickness, no deep grooves, no runout causing pedal pulsation... nothing wrong with them. If it stops smooth, and they've been inspected for any of the above - thickness, deep grooves, runout... if all that is fine, no need to do anything with them.

Brake sale and they wanted extra to turn the rotors?

GM has a bulletin (and in the service manual) that says if nothing is wrong with the rotors, no need to turn them during a pad replacement.
Just take the new pads out for a couple of firm stops in a row to bed them in, and it's good to go.

It's kind of like the cheap oil changes, they just get you in the door with the cheap oil change and then try to sell you a $25 air filter. When really all you need is that cheap oil change.

Brakes will tell you with your foot and ear if they really have a problem.
And an honest tech with a micrometer will tell you if you really need rotors.

cclive

How did Midas get a chance to tell you this...in other words, what was wrong with the brakes that made you take it in to be fixed?

Road Rage

chsmith112, here's some info so that you can make an informed decision in the future.

If brake temps become too great, localized impurities in the metal can be burned away, altering the structure of the metal and causing hard spots, also called chill spots, to appear. Hard spots are roughly circular, bluish/gold glassy appearing areas on the friction surface.

Hard spots create a number of problems including:

1. They are harder than surrounding areas of the friction surface, and do not wear at the same rate. Once the spots begin to stand out from the rest of the friction surface, they cause rapid brake lining wear.
2. The friction coefficient of hard spots is less than that of surrounding areas so braking power is reduced or becomes uneven. This can cause the brakes to chatter, or result in a hard or pulsating brake pedal.
3. A rotor is more likely to crack in the area of the hard spots than elsewhere.

Rotors should generally be replaced when hard spots are found. Besides, GM and most other makers put "throw away" rotors on their cars now days anyway. The days of turning/cutting rotors is going away in an effort to save weight.

Finally, my step-father operated 3 Midas shops in the 90's. I'd never go there.