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Some glazing on front brake rotors

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by ILuvMyPriusToo, Mar 10, 2015.

  1. ILuvMyPriusToo

    ILuvMyPriusToo Senior Member

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    2009 Gen II Prius with 73K miles. I had my state inspections done at the local Toyota dealership and the service manager told me I had "some glazing" on my front disk rotors (not the pads). He said it was *not* a safety issue (he was very clear on that when I asked) but that stopping distances might increase slightly. Recommended remedy was to have the rotors turned (for about $150). Pads are at "7" (mm?; original to the car) and fine, according to the tech. He said the condition might have occurred because of a lot of braking in stop and go traffic that led to the rotors heating up. I don't remember any situation like that recently. He said rotor glaze is permanent and will not wear off; hence the recommendation to machine, but I hate to lose the metal if it isn't necessary. The brakes otherwise seem fine - no wobbles, squeaks or other noticeable issues. Thanks in advance for insights and advice!
     
    #1 ILuvMyPriusToo, Mar 10, 2015
  2. bisco

    bisco cookie crumbler

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    i wouldn't do anything. maybe take it to a local shoppe and have them show you the disks.
     
    #2 bisco, Mar 10, 2015
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  3. 69shovlhed

    69shovlhed Surly tree hugger

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    put some valve grinding compound on the rotors and drive it, braking lightly. this will sometimes remove the glazing on normal cars, works great for brake squeaking.
     
    #3 69shovlhed, Mar 10, 2015
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  4. ChapmanF

    ChapmanF Senior Member

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    Ford's official shop manual for my old Bronco II advised against machining in cases of light glazing, and recommended hand sanding with 150 grit sandpaper instead. Seemed to work ok for me.

    I might think twice about grinding compound just because I'm not sure what the liquid is (if it's the kind of compound that comes in a tube like toothpaste). If it's only water I guess it would be ok. Something else, I might not want it on the brake linings.

    -Chap
     
    #4 ChapmanF, Mar 10, 2015
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  5. xpcman

    xpcman Senior Member

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    get up to 30 mph on a back road - put it into neutral - apply the brakes hard and come to a complete stop.
    do this 2 or 3 times and you should be OK.

    Remember the "service writer" works on commission !
     
    #5 xpcman, Mar 11, 2015
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  6. ChapmanF

    ChapmanF Senior Member

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    Good technique for brake noise caused by light surface rust after wet weather.

    Only makes glazing shinier.

    -Chap
     
    #6 ChapmanF, Mar 11, 2015
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  7. exstudent

    exstudent Senior Member

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    Couldn't OP do the same procedure as PriusChat member "Galaxee", did for the rear brake shoes and drums to remove glazing on both items?
    Rear Brake Clean and Adjust | PriusChat
    3. sandpaper the friction surface of the drum with aluminum oxide sandpaper- 80 grit wet or dry is what DH is using here. see how shiny that surface is? that's glazing. the glazing will be removed as well as brake dust. NEVER sand in the direction parts are moving. do not sand around the long surface, sand perpendicular to it. if you sand parallel to the long surface, you can score the surface, which you really do not want to do.​

    Take a medium or heavy grit sandpaper to the front disc rotor and front pads, going perpendicular to the direction of braking. Then clean the rotor and pads again w/ brake cleaner fluid?

    Logically if this works for deglazing the rears, shouldn't it work for the fronts?
     
    #7 exstudent, Mar 11, 2015
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