DBA4000 - Heat spot problems

[Amaru]

I fitted a set of DBA 4000 and Racebrakes RB74 pads to my R32 GTR (front) fitted with Brembo callipers from the V-spec/R33/R34. I bedded these in as per manufacturers instructions and since have only used the car for daily driving duties and light braking (discs are around 2 months/5000km old - no track days or heavy use).

They have developed severe heat spots on the disc, and not knowing much about brakes, just seeing if anyone else would know why this happens. I heard DBA had a batch of badly casted discs which caused similar problems, as I cannot think of anything else. As said these brakes have not seen severe use, just normal 100km/h and under slowing down to stop for traffic lights etc. The old brakes on there (slotted discs, unsure what brand and racebrakes rb74 pads) had no problems, and these I stomped on pretty hard at times and they never developed any of the above mentioned problems.

Any ideas or what should I do? From my limited understanding of brakes, I take it once heat spots develop the disc is basically stuffed?

EDIT: I also forgot to mention the heat spots have been developing since the discs were brand new and have been getting progressively worse.

[260DET]

Cleaned them up and tried a different set of pads? It could be that the binding or other material from the pads is the problem, from what you have described I can't see how the rotors could get hot enough to be the problem. But I'm no metalurgist :)

[dattoman1000]

I've never heard of a bad casting batch from DBA.......this is news.
Any idea when ?
Can you get all the roll markings off the edge of your discs ?
They will identify the date of manufacture. Batch from the foundry...and even the guy who did the machining and the colour of his undies that day.

I'd say its a pad thing.

[hotgemini]

Got photos of the rotors?

[Amaru]

Will get photos tonite and post them tomorrow (ive only got camera phone and the cars at home)

[Amaru]

Heres a picture of the discs... not a good picture, was taken with a camera phone, but you can see the heat spots.

[dattoman1000]

Hard to say
My guess is pad issue

Might pay to PM DBASteve for a look

[lambs]

Looks like the discolouration has a pattern to it that might suggest it's related to the structure of the internal cooling passages - or more specifically, the 'bridging' material between the disc faces. Local differences in heat conduction could give this discolouration, and it's not uncommon in cast irons. It's not really a problem unless there's cracking - doesn't look like it but it's not a good photo. That said, it looks like you've got some scoring...

[260DET]

Yeh, considering the use the rotors should not be worn like that. Pad problem, probably.