Blued disks....

Rich H · Post by **Rich H** » Sat Feb 25, 2006 9:43 pm

I have managed to blue all of my disks during todays run, no panicy braking just braking late I hasten to add!

Pads are greenstuff all round (~7mm) and the disks are OE irons, 7k miles old.

Should I be concerned? Only the outer edges of the disks and the inner unswept area of the rears are blue now. They still seem good and I never got any fade just a bit of a whiff of hot brakes.

Cheers

Rich

mac · Post by **mac** » Sat Feb 25, 2006 10:52 pm

yeah - be concerned.

You've overheated (and hence weakend) the discs.

Mac

Rich H · Post by **Rich H** » Sat Feb 25, 2006 11:03 pm

OK, now what then? Do I need a new set or will a skim suffice or can I jst monitor them? How do iron disks fail? I thought they warped and cracked, but there is no evidence of that yet, still apparently straight and true. (Will get them off tomorrow and check with steel rule)

I'm suprised that at that temp I didn't get any fade first. Maybe these greenstuff pads are better than I thought...?

Or maybe I have a heavy right foot and no proper braking skills....

mac · Post by **mac** » Sat Feb 25, 2006 11:12 pm

I'd be looking for some kind of sticking in the system TBH.

Discs warp when one area gets overheated and buckles (differental heat) blueing is normally cause by a consistent heat, eg constant pedal presure

Mac

Rich H · Post by **Rich H** » Sat Feb 25, 2006 11:25 pm

OK thanks, I'll get them all to bits tomorrow and have a look if the weather is ok.

They seem fine and exactly the same as before the run so if I don't find anything I'll just keep an eye on them for now.

TVM
Rich

Stephen · Post by **Stephen** » Sun Feb 26, 2006 12:31 pm

Rich,
so long as the disks are not too thin which they ain't and are not warped then they should be fine. check for any binding though.

mac · Post by **mac** » Sun Feb 26, 2006 12:36 pm

binding!

that's the word I was looking for.

Mac

Rich H · Post by **Rich H** » Sun Feb 26, 2006 12:51 pm

I'm going to wash her first, then I'll (Go and buy a torque wrench...) whip a wheel off and have a look.

Pics to follow hopefully.

Cheers
Rich

gordon · Post by **gordon** » Sun Feb 26, 2006 5:28 pm

Mine are always blue after a trackday. And i'm gonna have to shift my view and agree with the masses. Greenstuff aren't enough for hard track use. My brakes were fading a bit on sat, gave the car a run today to get the glazing off the pad and they're fine again.

Hmmmmm EF is gonna be fun braking from all these long straights. Gonna strip them, bleed then and clean/ buff pads/discs up to give them another go.

Rich H · Post by **Rich H** » Sun Feb 26, 2006 6:00 pm

Turns out I couldn't be bothered to get the wheels off as it's freezing outside and I'm too mean to buy a torque wrench when I can use one from work tomorow.

We'll see if I can be bothered tomorrow....