DBA rotors, EBC pads

[TheNewMonaro]

John,

Few people seem to be having trouble with DBA rotors warping when using Greenstuff or higher pads... I assume due to temp. getting too high.

Any particular reason? Is it actually a problem at all?

[Chad]

I also have heard this, but a person I know pointed out to me that, going from flat out driving (racing, downhills etc.) then stopping dead, and just letting them cool the rotors can warp, if they are "driven" down, where u say, have a 10 lap sprint, allocate teh last lap to cool down ur brakes, if not, go for a small drive, so u use the brakes, but not as harshly, so they get use evenly for a few minutes, that brings them down to a mroe normal temperature, then u can let them go cold. this also works for warming them up, with high qual pads they are going to not work immediately so they are going to need warming up, just like the rotors.

U understand what i mean??

hope it helps

Chad

[coyote]

Originally posted by TheNewMonaro
Is it actually a problem at all?

No.


The problem is as described above.

[gti6]

One thing to consider TNM is they just don't last. I bought Greenstuffs as a replacement (knowing they would wear fairly quickly) so I could use the backing plates down the track and get some custom jobbies made up. I didn't know I'd ruin them in 3 months of street driving (no track days or anything).

I happened to warp my front discs with them on too, but what Chad said is right. Another theory I have is if you've managed to get your pads very hot in city traffic, standing at a set of lights with your brake applied is going to put a lot of concentrated heat where the pad contacts the disc.

[dbasteve]

The rotors aren't always warping. ( rarely actually )

What happens is that under higher temperatures the pad deposits resin on the disc in irregular layers. This builds up causing a thickness variation on the disc. The result is brake shudder ( vibration ).

This is more apparent in the Cross drilled rotors than any others as the combination can generate more heat. European disc rotors are manufactured using a higher carbon iron than most other manufacturers and the pads are manufactured to suit. High carbon rotors wear much quicker than others also.
Our rotors are manufactured to give the maximum product life which requires a different iron composition. An iron designed for longer life and a pad designed for high carbon rotors results in problems like these.

We are constantly customising our product for compatability with most pad compounds but not at the expense of product life.
We have used EBC Blue pads on the track an they work very well.

[itsnotagsr]

Steve,

so the easiest way to "clean" them is just to have them machined and that should get rid of the resin?

In my car - once you get some temperature in the brakes they start to shudder under braking, but are fine under normal driving. Is this related to the pads not being sufficient temperture range to cope?

Thanks
Chris

[dbasteve]

Originally posted by itsnotagsr
Steve,

so the easiest way to "clean" them is just to have them machined and that should get rid of the resin?

In my car - once you get some temperature in the brakes they start to shudder under braking, but are fine under normal driving. Is this related to the pads not being sufficient temperture range to cope?

Thanks
Chris

You will probably notice a black smear around slots or holes, you could try to rub back this resin deposit with some emery paper to releive the problem. If that doesn't work then a light skim is the fix.
I beleive the reason the shudder increases with temperature is that the deposits on the rotor increase the bite on those areas as the rotor becomes hotter. This would result in an alternating friction coefficient around the disc.

[Nafe]

I put in some EBC Green Stuffs in my car the other weekend, and have noticed the "black smear" look on my front discs. Is this the resin buildup?

The pads have only been used on the street so far, without any heavy usage at all. I haven't noticed any drop in braking performance, the green stuff seem to bite nicely when cold and when warm.....although my car doesn't weigh much :)

[dbasteve]

Looks like this.!

http://www.dba.com.au/forum/resin_close.jpg

[itsnotagsr]

Thanks steve!

BTW when are kangaroo paws coming out for the early evo/vr4 series?

Thanks.
Chris

[dbasteve]

Originally posted by itsnotagsr
Thanks steve!

BTW when are kangaroo paws coming out for the early evo/vr4 series?

Thanks.
Chris

Late November 2002

[Nafe]

Originally posted by dbasteve
Looks like this.!


Hmmmm, looks similar, but mine seems to go around the disc completely! It hasn't hindered the braking performance....well, I haven't pushed the brakes yet though.
Will try and take a pic of them tonight/tomorrow morning to compare...

Thanks,
Nathan

[Jay95R33]

I didn't know I'd ruin them in 3 months of street driving

Holly crap !!!

I've had my Greenstuff's in for about 14 months (and about 18,000km) and they are still at 80% !!!

[gti6]

Well, actually - following DBAsteve's comments about the black resin forming on the disc, I noticed some black patches forming in the fine grain of the disc (my discs don't seem to be very smooth) so I bought some Brakleen spray and went a bit aggers on both sides of the disc. I did this as I've been encountering an intense brake shudder.

After a good clean, I put the wheels back on and did about 5 long, soft stops going down a hill. I sprayed a bit more on through the wheels, and did it again. Then I went a bit more aggressive and did a few high speed stops.

The braking seems much smoother, maybe that was part of my problem? At higher speeds, the judder is still there (I suspect there still is a bit of a warp) but the performance is noticably better - it felt like a clapped out taxi before, the brakes would pulse on and off all the way down to a stop.

I thought my Greenstuffs were stuffed, because they omitted a sporadic grinding noise when getting closer to a halt. Fortunately, when I cleaned the discs, I noticed the pads have a bit of life left in them it seems.

Also, after the clean, I can't reproduce the grinding noise - weird!

[dbasteve]

Originally posted by satria_gti


Hmmmm, looks similar, but mine seems to go around the disc completely! It hasn't hindered the braking performance....well, I haven't pushed the brakes yet though.
Will try and take a pic of them tonight/tomorrow morning to compare...

Thanks,
Nathan

If you have an even coating around the braking surface your doing fine.
This problem doesn't happen in all cases. We put these pads on one of our VT's and they were great.
Certain driving styles or applications tend to bring this on. Usually temperature orientated and usually when both disc and pads are fairly new.

[Nafe]

Originally posted by dbasteve


If you have an even coating around the braking surface your doing fine.
This problem doesn't happen in all cases. We put these pads on one of our VT's and they were great.
Certain driving styles or applications tend to bring this on. Usually temperature orientated and usually when both disc and pads are fairly new.

Thanks Steve,

The coating seems to be fairly even around the disc. Although the pads haven't fully bedded in yet. The discs are still relatively new (only travelled 23,000kms and none of it on the track), and the original pads had only worn about 2-3mm. I'll take some emery paper down to Wakefield just in case though :) Or maybe some of that Brakeleen stuff....

Nathan

P.S. do you know Terry Conroy?

[Boxer]

If pads are exhibiting this problem, does that mean they are stuffed?

[dbasteve]

Originally posted by Boxer
If pads are exhibiting this problem, does that mean they are stuffed?

Not necessarily, they have undergone pad fade which has brought resin to the surface.
If this happened quite ofen then you have an issue. When drained of resin the pad will start to break away at the edges ( usually trailing edge). When they start to crumble like this, then they are stuffed.

[dbasteve]

Originally posted by gti6
Well, actually - following DBAsteve's comments about the black resin forming on the disc, I noticed some black patches forming in the fine grain of the disc (my discs don't seem to be very smooth) so I bought some Brakleen spray and went a bit aggers on both sides of the disc. I did this as I've been encountering an intense brake shudder.

After a good clean, I put the wheels back on and did about 5 long, soft stops going down a hill. I sprayed a bit more on through the wheels, and did it again. Then I went a bit more aggressive and did a few high speed stops.

The braking seems much smoother, maybe that was part of my problem? At higher speeds, the judder is still there (I suspect there still is a bit of a warp) but the performance is noticably better - it felt like a clapped out taxi before, the brakes would pulse on and off all the way down to a stop.

I thought my Greenstuffs were stuffed, because they omitted a sporadic grinding noise when getting closer to a halt. Fortunately, when I cleaned the discs, I noticed the pads have a bit of life left in them it seems.

Also, after the clean, I can't reproduce the grinding noise - weird!

Our VT ( with Grenn Stuff) came in tonight for a check up after 8000 km and the right hand disc rotor looked like a Dalmatian :mad: . The left was fine. Our driver reported this grinding noise also, but no vibration yet. This noise started after a series of heavy braking. There appears to be a smear of pad material after each of the slots (12 Slot). I will take the discs off tomorrow to check them out.

[PodgeSSS]

So what is your reccomended combination, if EBC green stuff is causing problems with the DBA rotors ?

[dbasteve]

Originally posted by PodgeSSS
So what is your reccomended combination, if EBC green stuff is causing problems with the DBA rotors ?

We need to reassess pad materials in this range. With the elimination of asbestos and heavy metals in most of these pads, their characteristics have totally changed. Even a lot of the old faithful compounds.
The normal street pads like Bendix premiums ect and the high end pads like Pagid RS-4-2-1, Ferodo DS2000, Mintex 1155 are great. The U.S market has a large number of compatable pads in the middle range, but they're not so easy to source in Australia yet.

This is an issue that is being addressed.

[PodgeSSS]

So you suggestion Bendix instead ? or look after your EBC ?

[dbasteve]

Originally posted by PodgeSSS
So you suggestion Bendix instead ? or look after your EBC ?

Although it is our biggest problem combination a lot of people use EBC Greens without problems if you drive in a sensible manner.
Bendix are generally hassle free.

[dbasteve]

Originally posted by dbasteve


Our VT ( with Grenn Stuff) came in tonight for a check up after 8000 km and the right hand disc rotor looked like a Dalmatian :mad: . The left was fine. Our driver reported this grinding noise also, but no vibration yet. This noise started after a series of heavy braking. There appears to be a smear of pad material after each of the slots (12 Slot). I will take the discs off tomorrow to check them out.

Update.
We check out the discs and they still looked O.K so we left them on the car. After a few days the resin spots were gone and so was the noise. Everything is sweet again now and they are going well.

[sssgtr]

Originally posted by Jay95R33


Holly crap !!!

I've had my Greenstuff's in for about 14 months (and about 18,000km) and they are still at 80% !!!
I'm about the same. They don't wear THAT quickly.