okay, so I bought a junked A4 as a parts car a couple days ago, it looks like it was involved in some kind of racing or the like, no headlights/taillights, only the driver seat was left, upgraded exhaust, lowering springs, some sticky tires and the cat was cut out (I guess to coin it for some quick cash as a last resourt) it also had slotted rotors on it as well that looked almost brand new so I thought, hey! quick upgrade in prep for the BT. Well.. I have them on now and decided to re-use the old pads since they were pretty much brand new(from my car, not the parts car, they're onki-bono ceramics), I sanded them down pretty good on a level surface to get rid of any unevenness. However, now all four brakes are dusting like crazy, it's been only 3 days and mabye only 120miles since I completly cleaned the wheels with simple green and a rag when I was bleededing them so I'm wondering; could this be because they're acutaly racing slotted rotors and are cutting the pads to a clean surface every time I brake or could it be that there's some kind of resedue on the rotors like anti-seize or the like that's doing this? I also noticed that the rotors look kinda weird, they're not really *glazed* over like the cross-drilled/slotted rotors are on my mazda, it's almost like it's just brake dust and some kind of resedue looking stuff..

I'll grab some pictures if it helps.

 

Cross drilled or slotted rotors will shave the pads down quicker than a blank rotor due to the edges of the holes, so yes, you'll get more dust. They most-likely will not help your car stop any better. If the brake dust is bothering you, I would switch back to blank rotors.

A good read:

http://www.stagefourmotorsports.com/tech_rotors.php

 

i got this problem too once i changed rotors (i still have plain though not slotted or drilled) and also changed to ceramic pads.
my original OEM pads and rotors didn't dust as much. I bought ceramic thinking that they were supposed to reduce dust.
However, the dust just wipes right off, whereas w/ my OEM pads they would sort of "burn into" the rims making a permanent stain.
The only thing i can think of is that it's either supposed to be like that (wipeable) or that since the pads are still new, they haven't been broken in yet????

 

I figured there would be a increase but I'm talking about an extreme increase, there's more brake dust accumulated in these past 3 days that would have accumulated within 3 weeks with the blank rotors. I might try turning them to see if maybe they were cut so that the slots really chop the pads up.
ehh.. they're at least 10,000 miles old, but there's tons of pad left.

 

Slotted or cross-drilled rotors shouldn't really be machined as it can damage the lathe or the rotor in the process. They are supposed to be ground-down, but most places don't bother because you end up grinding down the slots or make the rotor thin enough to accelerate cracking or warping.


You could do one of two things:

1. Drive on them long enough to allow the pads to bed-in and you should see less dusting

or

2. Put blank rotors back on. You'll stop better and have less dust.