blue pattern on discs

[hman]

Long story short,

New pads, discs with 20,000 on them, autobahn,

155-60mph full anchors, afterwards vibration without brakes off above 70, worse with brakes on,

Improves over time, practicaly goes away couple of days after.

Just noticed- blue uniform spaced vertical striping all the way around disc surface.

wtf is the blue striping about?

[martycossie]

cheap discs blue ring is when u braket made heat buld up

[hman]

ha, thanks for your insightful reply.

BTW the discs are Audi OEM.

Anyone else got any more detail apart from brakes get hot when you brake...

[mi1ne]

fair chance the discs have warped with the heat, new discs should sort it out. but thats without having a proper look obviously.

[paintman]

Are they vented discs & if so does the vertical striping coincide with the webs in the disc?
As for the vibration get the discs checked for run-out.

[hman]

paintman said:

Are they vented discs & if so does the vertical striping coincide with the webs in the disc?
As for the vibration get the discs checked for run-out.

discs are vented, havent checked if they coincide with the webs, if they do what is the relevance?

how do I get the discs checked for run out?

[paintman]

hman said:

how do I get the discs checked for run out?

With a dial gauge. Best get a garage to do it for you unless you want to buy one.
You may find these of interest. http://www.juratek.com/support-discs.php and http://www.gunite.com/literature/pdf/discbrak.pdf

Edited by paintman on Tuesday 24th November 00:56

[hman]

ok, so the gunite site reckons that its heat checking and that this is normal.


I have not experienced the vibration under braking for the last couple of weeks so presume that it must have been part of the wearing in process + overhaeting the pads and discs during this running in process probably exasperated it.

If I experience the vibration again I will arrange for someone to get a dial guage on the discs and measure for run out.