Brake Discs - 2 part question

[Zilli]

A far fetch, but did you over torque your wheel nuts? I have heard that can cause wheel hub and rotors to deform.

the ford link above said this... but i cannot see how a peice of metal (the hub bit of rotor) that is compressed against the flat reverse side of the wheel can actually deform the entire disc?

yes ive used a rattle gun on them...

[Integral]

Zilli,

We found DBA4000's with Hawk HT10's to be a very good combination on our DC2 race car.

[tinkerbell]

so what you're saying is the weak link is most probably the breakin the mechanic did?

yes. have you asked him how he did it? i always get new pads smoking like whores after installation, then they have always been fine afterwards.

IIRC it is something about the glue inside them or something?

ahhhhh, yes:

With respect to the pads, the bonding resins must be burned off relatively slowly to avoid both fade and uneven deposits....

You should begin to smell pads at the 5th to 7th stop and the smell should diminish before the last stop...

they will *feel* normal on the street, if not broken in properly, so:

What i dont get is why then did everyhting work fine at the beginning?

they need to be broken in before driving normally though...

because once you heated them up fully at the track, you broke them in on the track, which is no good as it is "too late" to break them in properly...

and why they started playing up after the track day...

in my opinion...

[tinkerbell]

Zilli,

We found DBA4000's with Hawk HT10's to be a very good combination on our DC2 race car.

price for the Hawks?

my ferodo's are getting thin...

[Zilli]

cheers Dave, some really good points...

i've lost the paperwork i had for the run in procedure for the Ferodo's do you have them?

I found a local guy that's gonna come and do the front rotors on Wednesday evening... mobile disc machining...

[VTECMACHINE]

How do you guys bed in your pads??

[tinkerbell]

i've lost the paperwork i had for the run in procedure for the Ferodo's do you have them?

are you getting new ones?

[Zilli]

no, the ones i have there have less than 5000 kms on them... im gonna use the old ones just do the bed in procedure again

[tinkerbell]

hmmm, OK...

maybe call them to discuss?

http://www.ferodo.com.au/contact.php

they might have a better idea altogether!!!

and ask the disc machining guy what he thinks

[Zilli]

thanks Dave

[Zilli]

So an update

I found a local bloke (Ace Mobile Disc Machining) who came out yesterday and machined the discs. He actually measured them up and he gave the following diagnosis

1) Discs warped - explaing how i had used them to him, he said it could have been the heating up of the rotor too quickly, possibly due to not getting a proper heat cycle into them before hitting the track, but also possible due to the use of a rattle gun to tighten the wheels back on... he told me to never use the rattle gun to put the wheels on, and if i need to take the discs off to mark them and get them oin exactly the right way in the future, as the hub part may be slightly untrue

2) sectioned - A trait of slotted rotors apparently, where the trailing endge of the slot gets more wear as it is the first thing to hit the edge of the pads, eventually this creates "sectioning" from slot to slot... he explained how it affected his VK race car.

He explained that the best thing to do is use quality, blank rotors, which kinda makes sense, and reminds me of the guy at Race Brakes trying to sell me the Brembo rotors when i got the DBA, they were blanks, but the wanker in me wanted slotted!

All in all, lesson learnt, he did say that this may happen again, and the best way to mitigate it is to give them a good solid heat cycle as a bed in before any more road and circuit duties...

and he did them for $90 on the car!

will update when i bed them in again.