1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Can you Skim Wave Discs?

meph137 Oct 1, 2018

  1. meph137

    meph137 Active Member Audi S4 Black Edition

    302
    55
    28
    Hey all, I have an S4 but the previous owner upgraded to RS4 (or 5, I can't recall - I think they're the same) brakes, i.e. the ones with the wavy edge. It's come time to change pads and I don't fancy spending £700 on new discs as well so wanted to skim them (never been done before so they should have plenty of material in order to do so), for which I'd go to one of the pro cut lathe centres to have the on-car skimming. Problem is, I'm not sure the lathe would cope with a wavy edge disc.

    Has anyone had one skimmed before?
     
  2. Avatar

    Google AdSense Advertisement


  3. no_idea

    no_idea Active Member

    383
    218
    43
    Have you actually measured the thickness? The RS4 discs only have a 2mm wear allowance.
    I replaced my discs and pads at 30k.

    Sent from my Pixel 2 XL using Tapatalk
     
  4. meph137

    meph137 Active Member Audi S4 Black Edition

    302
    55
    28
    I haven't actually, I will check them later. Hopefully they're within tolerance otherwise it's an expensive game when it comes to brake pad change time!
     
  5. meph137

    meph137 Active Member Audi S4 Black Edition

    302
    55
    28
    Just done a very quick rainy in-the-dark measurement and they’re coming up as 11.15mm - don’t suppose you know the minimum thickness do you? :) otherwise it’s an Internet hunt..


    Sent from my iPhone using Tapatalk
     
  6. meph137

    meph137 Active Member Audi S4 Black Edition

    302
    55
    28
    That’s one side obviously, not the whole lot. Might be the wrong way to measure!


    Sent from my iPhone using Tapatalk
     
  7. no_idea

    no_idea Active Member

    383
    218
    43
    Front discs start at 34mm and minimum thickness is 32mm or 32.4mm, I can't remember off the top of my head. It is on the disc bell.
    I can check tomorrow if you want?
    Not sure what thickness you have measured?

    Sent from my Pixel 2 XL using Tapatalk
     
  8. no_idea

    no_idea Active Member

    383
    218
    43
    Ah I see, you need to measure the total thickness.

    Sent from my Pixel 2 XL using Tapatalk
     
  9. meph137

    meph137 Active Member Audi S4 Black Edition

    302
    55
    28
    Yeh I only did one side, I.e one side of where the cooling veins where. I was distracted :D I shall measure them correctly tomorrow morning.


    Sent from my iPhone using Tapatalk
     
  10. meph137

    meph137 Active Member Audi S4 Black Edition

    302
    55
    28
    Couldn’t see the measurement on the disc for min thickness but mine seem to be 33.3mm, maybe a smidge over.


    Sent from my iPhone using Tapatalk
     
  11. no_idea

    no_idea Active Member

    383
    218
    43
    It's on the disc bell, but if they have turned black and are covered in crud you may not see it.
    If they are that thickness you will get away with a skim, but to be honest unless they are heavily scored I would leave them as you are only taking away precious material. Maybe take the lip off, if there is one.

    Sent from my Pixel 2 XL using Tapatalk
     
  12. Avatar

    Google AdSense Advertisement


  13. meph137

    meph137 Active Member Audi S4 Black Edition

    302
    55
    28
    I never know really what to do with discs. People say do discs and pads at once but do people really replace discs that cost £700 after one set of pads? That seems madness.


    Sent from my iPhone using Tapatalk
     
  14. RAF_S7

    RAF_S7 Well-Known Member Team V8 Gold Supporter Team Sepang Audi S7 A7 Owner Group Black Edition

    1,357
    746
    113
    In my 35+ years of car ownership, I’ve never had to skim disc’s for a pad change.

    Are yours that bad? Pictures? :racer:
     
  15. meph137

    meph137 Active Member Audi S4 Black Edition

    302
    55
    28
    I’m not doing it because I think they look bad to me but rather because the advice seems to be to always replace discs and pads at the same time, and I’d rather not spend £700 of new discs if I can avoid it.


    Sent from my iPhone using Tapatalk
     
  16. RAF_S7

    RAF_S7 Well-Known Member Team V8 Gold Supporter Team Sepang Audi S7 A7 Owner Group Black Edition

    1,357
    746
    113
    Unless your discs are corroded, or below manufacturers recommended minimum thickness, I’d just change the pads.
    The main thing with fitting new pads on “used” discs is that there is a bedding in period before full braking efficiency is reached.

    Save the £700.....

    :racer:
     

Share This Page