glazed brake discs
Discussion
had tognola in datchet change my brake fluid, oils etc and general check up.
they said my discs were pretty crap due to them being glazed. any ideas how this is caused? is it a particular type of braking that leads to this (bearing in mind i use the car 90% for tracking). clealry the braking involved is going to be heavy, but is it more likely to happen over short sharp heavier braking or longer periods of less heavy braking?
they said my discs were pretty crap due to them being glazed. any ideas how this is caused? is it a particular type of braking that leads to this (bearing in mind i use the car 90% for tracking). clealry the braking involved is going to be heavy, but is it more likely to happen over short sharp heavier braking or longer periods of less heavy braking?
p.s. given your disks are steels, it all likelihood they will start to crack before wearing in any other fashion that requires replacement (i.e. going thin).
If you need replacements, I'd talk to JZ Machtech about the Alcon semi floating discs they have for RSs as assuming they fit they will last a lot longer.
Some of the details may have been lost in translation, but glazing in the normal sense isn't something that would apply to brake discs because they don't mechanically bed in to the pads in the way that bearing surfaces do. But there is a common problem of surface contamination where the surface of the rotor becomes unevenly impregnated with pad material, and this can cause variations in friction, leading to local overheating, leading to local changes in the structure of the disc at the microscopic level, leading to uneven wear, leading to more local overheating, etc. In the early stage you can correct this by bedding the pads in again. If the discs are too far gone you need to remove the surface layer, skimming is one way to do this. It's worth emphasizing that this is to correct changes in the structure of the surface of the disc, NOT because the disc has warped (which is often blamed for the problem).
Peter Tognola is one of the most experienced 911 men around ,is booked out week in week out and doesnt need to drum up business selling discs ........politely suggest anything he says is well worth listening too..............he runs a 993 clubsport for his own satisfaction track days and looks after a host of similar kit from old to brand new..................
Had this before,, get some fine/medium grade emery paper. remove pads,,rub surface on emery to make sure they are flat. Then gently rub the surface of the disc ( on both sides) with emery. The disc should turn matt from it's previous mirror finish.
Reassemble pads, this should do the trick!
Reassemble pads, this should do the trick!
Well said Vic. If Tog's says the disks are glazed then they are. I used to have to de-glaze the disks on my race car all the time, using emery cloth as clubsport suggests. I thought this was an excessive build up of the residue given off from the pads that then hardens.
This is also something you will be told if you change pads to something like Pagid's. If the company selling them know what they are doing they will tell you to de-glaze the disk to remove the residue left by previous pad or it will impact the bedding in process of the new pad and affect the performance of it.
This is also something you will be told if you change pads to something like Pagid's. If the company selling them know what they are doing they will tell you to de-glaze the disk to remove the residue left by previous pad or it will impact the bedding in process of the new pad and affect the performance of it.
Take a look at this link for lots of detailed techie information on brakes and brake problems:
www.stoptech.com/whitepapers/warped_rotors_myth.htm
www.stoptech.com/whitepapers/warped_rotors_myth.htm
Gassing Station | Porsche General | Top of Page | What's New | My Stuff