Ray Calvo

About 14K miles ago I installed ATE slotted rotors on the front of my '98.5 A4 Avant. This was an attempt to eliminate the wet braking problem I (and many others on this forum) have had. Well, they really helped - for awhile!

Recently, the wet braking delay came back. On doing a little investigation, I noticed the brake rotor slots were completely coated over with brake dust/residue, so I was back to plain rotors again! Removal of this residue required removal of the rotors and practically gouging the residue out with a thin bladed screwdriver.

While I was doing this, I looked at the rotors. They are definitely worn down; the slots are very shallow now due to the worn-down rotor surface. I really think that by about 20K miles of use, these rotors will require replacement. The pads are Pagids, replaced at the same time as the rotors. They look almost like now. So, I likely will NOT be replacing the rotors with the ATE slotted rotors again. Don't know what I will try, but seems like the EBC rotors get good recommendations.

OK, now on to drilled rotors. The holes on these have a tendency to clog up with brake residue too. I haven't tried them on the A4, but this is my experience on two different Porsche 911s. In addition, the rotors tend to start cracking radially outwards from these holes. The residue can be cleaned out by using a drill that is slightly smaller than the rotor holes; a quick shot on each hole when you have the wheel off will clean them up. Also, at each car wash, give the holes a good blast with the water hose on a high velocity discharge setting.

maaliish

Had ATEs, groves needed to be cleaned once a week. Replaced with Zimmerman X-drilled - Love'em.

SmokeyA4turbod@ebay

Never had that problem in 3 years i used EBC greenstuff pads tho

nanotech

Interesting...

Dave Griswold

Wet didn't seem to be a problem either...

SmokeyA4turbod@ebay

give the water someplace to go.

Joe N.

And have you driven in heavy rain multiple times with your new brake set-up? Just curious. Thanks.

Joe N.

I also have a 98.5, and I also have the horrid wet-braking problem. I figured the slotted rotors would have a good probability of being covered with brake residue over time, but they're probably still better in wet-braking than just OEM rotors. When it is time (I guess I can say this since I live in Southern Cali), I will try a cross-drilled set-up with the wet-brake "winglet" kit that Audi offers. Hopefully the combination will nearly eliminate the problem.

Dave Griswold

Yes, I had the wet braking problem before. Only driven in heavy rain once since the install, though