From "AOL Auto Questions"

Discussion in 'General Motoring' started by Dave L, Mar 14, 2008.

  1. Dave L

    Dave L Guest

    I ran into this today and thought a couple parts of this article were
    interesting, particularly the differences between different octane gas and
    whether to let the car warm up before driving. The top section about
    squeeking brakes - almost sounds like they're promoting re-surfacing the
    roters for each brake job to keep them from squeaking. I've changed brakes
    before withought re-surfacing and never had a problem. Opinions?

    http://tinyurl.com/34du4y

    -Dave
     
    Dave L, Mar 14, 2008
    #1
  2. Dave L

    Ph@Boy Guest

    I read the article and thought it was general at best. A lot lacking,
    and a bit off mis information concerning the topic of hydroplaning.

    Yes, you can get away with not resurfacing rotors, but it's not the
    preferred or recommended manner normally to do a brake job.

    If you have a heavily grooved rotor you will notice that the worn pad to
    be replaced has the exact matching grooves in it.

    The new replacement has of course has a flat surface that will have to
    wear in to the rotor to obtain the greatest breaking surface. That can
    take time and braking performance in a panic situation can suffer.

    Resurfacing also removes any warp.

    I could go on, but I'm sure others will have many other reasons as well.

    Resurfacing rotors is a good thing.

    OBTW, the biggest factors for hydroplaning are speed of the vehicle and
    tire pressure. Tread and water depth make little if any difference.
     
    Ph@Boy, Mar 14, 2008
    #2
  3. Dave L

    Ph@Boy Guest

    I read the article and thought it was general at best. A lot lacking,
    and a bit off mis information concerning the topic of hydroplaning.

    Yes, you can get away with not resurfacing rotors, but it's not the
    preferred or recommended manner normally to do a brake job.

    If you have a heavily grooved rotor you will notice that the worn pad to
    be replaced has the exact matching grooves in it.

    The new replacement has of course has a flat surface that will have to
    wear in to the rotor to obtain the greatest breaking surface. That can
    take time and braking performance in a panic situation can suffer.

    Resurfacing also removes any warp.

    I could go on, but I'm sure others will have many other reasons as well.

    Resurfacing rotors is a good thing.

    OBTW, the biggest factors for hydroplaning are speed of the vehicle and
    tire pressure. Tread and water depth make little if any difference.
     
    Ph@Boy, Mar 14, 2008
    #3
  4. Dave L

    EdV Guest

    I had my RAV4's rotors resurfaced only after changing the pads and the
    squeeling didn't disappear. After resurfacing it was totally gone. I
    guess my opinion would only to resurface if you are having problems,
    otherwise don't waste your money fopr the resurface
     
    EdV, Mar 14, 2008
    #4
  5. Dave L

    EdV Guest

    I had my RAV4's rotors resurfaced only after changing the pads and the
    squeeling didn't disappear. After resurfacing it was totally gone. I
    guess my opinion would only to resurface if you are having problems,
    otherwise don't waste your money fopr the resurface
     
    EdV, Mar 14, 2008
    #5
  6. Dave L

    Tegger Guest



    My objection to resurfacing is that many garages do not seem to care for
    their brake lathing equipment properly.

    A dull or mispositioned bit will make an absolutely horrible "new" surface
    on the rotors. Such a surface can glaze up in a big hurry.

    If you are guaranteed a quality lathe job, go for it. But if there is /any/
    suspicion of lathe quality, either replace the rotors or just put the new
    pads on the old surface (provided your new pads are the same as the old
    ones).
     
    Tegger, Mar 14, 2008
    #6
  7. Dave L

    Tegger Guest



    My objection to resurfacing is that many garages do not seem to care for
    their brake lathing equipment properly.

    A dull or mispositioned bit will make an absolutely horrible "new" surface
    on the rotors. Such a surface can glaze up in a big hurry.

    If you are guaranteed a quality lathe job, go for it. But if there is /any/
    suspicion of lathe quality, either replace the rotors or just put the new
    pads on the old surface (provided your new pads are the same as the old
    ones).
     
    Tegger, Mar 14, 2008
    #7
  8. Dave L

    Ph@Boy Guest

    You're absolutely right Tegger. Some guys haven't changed a seven dollar
    insert in years if ever!

    Setup by a knowledgeable operator is key as well.

    It really a disservice to a customer when you just hog off all the iron
    on the thinest rotor or largest diameter drum and not take into account
    the others and just turn them down to the same dimension. Most don't
    demand it, but on some high end vehicles this must be done and the
    customer should be informed.

    Some guys just want to sell rotors, or how many jobs can I get through
    this machine to pay for it and the mechanic, not build a new customer to
    be a return.
     
    Ph@Boy, Mar 14, 2008
    #8
  9. Dave L

    Ph@Boy Guest

    You're absolutely right Tegger. Some guys haven't changed a seven dollar
    insert in years if ever!

    Setup by a knowledgeable operator is key as well.

    It really a disservice to a customer when you just hog off all the iron
    on the thinest rotor or largest diameter drum and not take into account
    the others and just turn them down to the same dimension. Most don't
    demand it, but on some high end vehicles this must be done and the
    customer should be informed.

    Some guys just want to sell rotors, or how many jobs can I get through
    this machine to pay for it and the mechanic, not build a new customer to
    be a return.
     
    Ph@Boy, Mar 14, 2008
    #9
  10. Dave L

    Dave L Guest

    It was general but I think that's what they were trying to do to simplify
    each situation. The topics that caught my eye were the ones I see being
    debated on these groups from time to time. The use/reasons for the
    different octane fuel, whether it's good to really warm up a car and whether
    rotors should be re-surfaced.

    I know re-surfacing removes any warp but if the brakes are replaced before
    any pulsating starts I thought having the rotors turned wouldn't be
    necessary... Besides, wouldn't re-surfacing increase the tendency for it to
    warp again?

    I agree speed and tire pressure affect hydroplaning - but so do the tread
    pattern/compound. I used to have the Bridgestone Potenza RE-960 on a
    Prelude and they were the best tires I've ever used on wet roads. Almost
    felt like I was driving on dry pavement and cannot remember ever
    hydroplaning, whether it was light or heavy rain. Very stable and solid.
    Snow was a different story - they were awful! It was a trade-off. However
    nothing beats common sense!

    -Dave
     
    Dave L, Mar 15, 2008
    #10
  11. Dave L

    Dave L Guest

    It was general but I think that's what they were trying to do to simplify
    each situation. The topics that caught my eye were the ones I see being
    debated on these groups from time to time. The use/reasons for the
    different octane fuel, whether it's good to really warm up a car and whether
    rotors should be re-surfaced.

    I know re-surfacing removes any warp but if the brakes are replaced before
    any pulsating starts I thought having the rotors turned wouldn't be
    necessary... Besides, wouldn't re-surfacing increase the tendency for it to
    warp again?

    I agree speed and tire pressure affect hydroplaning - but so do the tread
    pattern/compound. I used to have the Bridgestone Potenza RE-960 on a
    Prelude and they were the best tires I've ever used on wet roads. Almost
    felt like I was driving on dry pavement and cannot remember ever
    hydroplaning, whether it was light or heavy rain. Very stable and solid.
    Snow was a different story - they were awful! It was a trade-off. However
    nothing beats common sense!

    -Dave
     
    Dave L, Mar 15, 2008
    #11
  12. Dave L

    Dave L Guest

    I never considered the equipment used to resurface the rotors. Good point!

    -Dave
     
    Dave L, Mar 15, 2008
    #12
  13. Dave L

    Dave L Guest

    I never considered the equipment used to resurface the rotors. Good point!

    -Dave
     
    Dave L, Mar 15, 2008
    #13
  14. Dave L

    Dave L Guest

    I had my RAV4's rotors resurfaced only after changing the pads and the
    squeeling didn't disappear. After resurfacing it was totally gone. I
    guess my opinion would only to resurface if you are having problems,
    otherwise don't waste your money fopr the resurface



    Exactly how I feel, unless something convinces me otherwise!

    -Dave
     
    Dave L, Mar 15, 2008
    #14
  15. Dave L

    Dave L Guest

    I had my RAV4's rotors resurfaced only after changing the pads and the
    squeeling didn't disappear. After resurfacing it was totally gone. I
    guess my opinion would only to resurface if you are having problems,
    otherwise don't waste your money fopr the resurface



    Exactly how I feel, unless something convinces me otherwise!

    -Dave
     
    Dave L, Mar 15, 2008
    #15
  16. Dave L

    C. E. White Guest

    I beg to differ. I can't speak for Toyota, but I know Ford and GM
    specifically says resurfacing is not required when replacing pads unless the
    rotor is damaged. And then only minor damage can be cleaned up. Significant
    groving requires rotor replacement. Futhermore, Ford only recommend
    resurfacing rotors on the car. Unless the brake lathe is in great condition,
    the chances of it making things worse are significant. Unless the car
    already has warped or otherwise damaged rotors, I see no reason to routinely
    turn brake rotors. I know most independent shops routinely turn brake
    rotors. They usually give a couple of reasons, but in many cases the main
    reason is extra profit or just habit.

    See:
    http://www.encyclopedia.com/doc/1G1-92137449.html
    http://www.aa1car.com/library/2003/bf110322.htm
    http://www.stoptech.com/tech_info/wp_warped_brakedisk.shtml
    Oh boy.......you really need to clarify this. See
    http://www.nhtsa.dot.gov/cars/rules/rulings/TPMS_FMVSS_No138/part5.6.html .
    You statement is misleading at best. Speed is a major factor for sure. But
    tread depth is not the trival factor that you impy in your statement. Tire
    inflation pressure is a major factor once "water depth exceeds the
    capability of the tread design to remove water." So for minimal depth of
    water and good condition tread, tire inflation pressure is not a bigger
    factor that depth of water and tread. Furthermore the formula used is pretty
    lame since it does not account for sidewall stiffness. Try applying the
    forumla to a run flat tire with all the pressure released and get back to
    me.

    See also:

    http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=3


    Ed
     
    C. E. White, Mar 17, 2008
    #16
  17. Dave L

    C. E. White Guest

    I beg to differ. I can't speak for Toyota, but I know Ford and GM
    specifically says resurfacing is not required when replacing pads unless the
    rotor is damaged. And then only minor damage can be cleaned up. Significant
    groving requires rotor replacement. Futhermore, Ford only recommend
    resurfacing rotors on the car. Unless the brake lathe is in great condition,
    the chances of it making things worse are significant. Unless the car
    already has warped or otherwise damaged rotors, I see no reason to routinely
    turn brake rotors. I know most independent shops routinely turn brake
    rotors. They usually give a couple of reasons, but in many cases the main
    reason is extra profit or just habit.

    See:
    http://www.encyclopedia.com/doc/1G1-92137449.html
    http://www.aa1car.com/library/2003/bf110322.htm
    http://www.stoptech.com/tech_info/wp_warped_brakedisk.shtml
    Oh boy.......you really need to clarify this. See
    http://www.nhtsa.dot.gov/cars/rules/rulings/TPMS_FMVSS_No138/part5.6.html .
    You statement is misleading at best. Speed is a major factor for sure. But
    tread depth is not the trival factor that you impy in your statement. Tire
    inflation pressure is a major factor once "water depth exceeds the
    capability of the tread design to remove water." So for minimal depth of
    water and good condition tread, tire inflation pressure is not a bigger
    factor that depth of water and tread. Furthermore the formula used is pretty
    lame since it does not account for sidewall stiffness. Try applying the
    forumla to a run flat tire with all the pressure released and get back to
    me.

    See also:

    http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=3


    Ed
     
    C. E. White, Mar 17, 2008
    #17
  18. Dave L

    Ph@Boy Guest

    I've noticed the auto manufacturers are in that same extra profit and
    habit mode as well on every new one pumped out.

    All I can say Ed, is never do yours. Most people come into a shop with
    the pad backing plate, if not a piston ground into at least one of the
    rotors, wondering what is that funny noise and the vibration in the
    brake pedal?
    8.7 times the square root of the tire pressure is the formula to
    calculate hydroplane speed in general. It's pretty reliable unless you
    need to go into some physics calculations.

    Tire tread depths vary greatly. Most folks don't buy specialty tires.
     
    Ph@Boy, Mar 19, 2008
    #18
  19. Dave L

    Ph@Boy Guest

    I've noticed the auto manufacturers are in that same extra profit and
    habit mode as well on every new one pumped out.

    All I can say Ed, is never do yours. Most people come into a shop with
    the pad backing plate, if not a piston ground into at least one of the
    rotors, wondering what is that funny noise and the vibration in the
    brake pedal?
    8.7 times the square root of the tire pressure is the formula to
    calculate hydroplane speed in general. It's pretty reliable unless you
    need to go into some physics calculations.

    Tire tread depths vary greatly. Most folks don't buy specialty tires.
     
    Ph@Boy, Mar 19, 2008
    #19
  20. Dave L

    ep45guy Guest

    .. They usually give a couple of reasons, but in many cases the main
    I am not a professional or even a particularly good DIY mechanic (just
    for the record). I think most shops resurface rotors to avoid 'come
    back' problems with noise etc. on brake jobs.

    On my own cars, I never turn the rotors unless there is a specific
    need. I know the 'theory' is to make the flat surfaces of the pad/
    rotor match, and to take off any rust or other problems with the
    rotor. But even if a rotor is not perfectly flat after a bit of
    driving the pads will mate to the rotor and if there were no noise
    problems with the old pads there shouldn't be any with the new. Any
    time you cut a rotor you are, of course, taking off metal - why do
    that if it isn't necessary? Its not just a 'cost' issue.

    I also agree with the poster who noted that not all shops use the
    brake lathe that well - in fact, I think proper turning of rotors may
    very well be a dying art. In the hands of a skilled operator, a rotor
    can literally be brought back to life 'from the dead' - but like so
    many other things you don't just slap the rotor on the machine and
    take a cut.

    My opinion, FWIW.
     
    ep45guy, Mar 19, 2008
    #20
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