Pebbles behind rear rotors- easy DIY fix

[CarJunkie]

I have this issue routinely whenever I autocross or go to the track. There is inevitably gravel to drive over somewhere, and sticky tires coming off the track will pick it up and throw it around. A few pebbles find their way behind the rotor and then won't come out. This car has always done that, and I get strange looks in the paddock because of it. I've never heard any other car making so much noise from pebbles between the rotor and the dust shield.

The design makes it clear why. The dust shield has openings near the hub which is where the rocks get in, and then there is a flange with a very tight tolerance all the way around the perimeter of the rotor. I almost always have to pull at least one rear rotor to get the pebbles out, otherwise they make a ridiculous amount of noise at low speeds in parking lots. It sounds like something is about to fall off.

Problem solved!

I took the rotor off to remove the pebbles this morning after yesterday's track day. I had already needed to trim the dust shield previously to get my Stoptech ST40 calipers to clear, and I decided to go ahead and trim the flange creating a small opening at the bottom where the rocks should be able to come out without having to pull the rotor every time I come back from the track. I made two cuts, and folded back the flap after filing all of the edges to make sure there's nothing sharp.

For reference, pictures show the openings near the hub that let the rocks in, the trimming that was required to fit the caliper, and my nice new rock exit window from both sides. If you are regularly going to the track or autocross at any site that has gravel around, this is a must.

I'll report back after my next track day….hopefully it will be the first with no pebble noise!

[ayao]

Thanks for posting this. I too have had the clankety-clank in the paddock leading to raised eyebrows. It has been bad enough at times that they noticed it when I was gridding — they were going to send me back to the pits to get the car “fixed”.

[CarJunkie]

Originally Posted by ayao

Thanks for posting this. I too have had the clankety-clank in the paddock leading to raised eyebrows. It has been bad enough at times that they noticed it when I was gridding — they were going to send me back to the pits to get the car "fixed".

Yup. I have to explain it every. damn. time. Never again, I hope!

Plus, my 12 y/o asked me what was falling off when I unloaded from the trailer and pulled into the garage. I have critics everywhere!