The rehabilitation of my 2011 grand sport continues. Car has 70,000 miles on it, so rotors and/or bearings could be needing to be done. Long story short, did some spirited driving and wanted to test out the brakes the other day, so I did some fairly aggressive stops from 60 down to 15 miles an hour or so. After, I started noticing some noise and feeling from what felt like the driver front wheel (felt it in the floorboard as well).

Drove it easy home and the next day, but the sound and feeling got worse. Also, the brake pedal feeling started to weaken and was very mushy. So now I’ve got it up in the air on jackstands and I’m spinning the wheels and they’re definitely seems to be some catching points. Both the driver and passenger side.

When I bought the car, the guy I bought it from said he had a shop put all new brake pads all around, and when I looked at the receipts, I noted that they had also recommended rotors. He declined the rotors. So that’s leading me to believe that the rotors definitely have some spots on them and it’s time for a replacement. See the video below where I show the noise while spinning the wheel and let me know if you’ll think this is rotor related or bearing related to both?

 

Got the rotors off, so I could isolate and see the bearing noise. Does this amount of noise seem normal? The driver side is harder to rotate in the passenger side, but it’s not hard. It just has some resistance.

 

I’d be changing out the bearings for sure. Bearings should not make that gravel sound. Now having said that if your rotors have 70,000 miles on them I’d change them too. Do it all at once.

 

Agreed. Already ordered new rotors and will be looking for new bearings for the front.

 

Car was factory built for autocross,

If your going to high speed road course track the car with R grip type tires, then replace the wheel bearing with SKF race wheel hubs.
Hence OEM wheel hubs, on the higher G demand cornering with added grip, will do in stock wheel hub bearings and no time.

Also, there are standard SKF hubs, and SKF race hubs for increase G rating side loading racing loading, so make sure your replacing the wheel hubs with the race hubs.
Also to point out, if you do have the talent to pushing the car to its edge, then brake shoes are the next to change out, since the oem pads do not have the needed heat range as well. Hence if you have a set of say A8's on rims for track use that you are swapping out for road course use, then standard tires on rims for street use, get do race pads at the same time that will not cross contaminant the rotors, that you want to swap out at the same time as tire swaps at the track.

Also, on the rotors, ditch the drilled rotors for street/autocross use, and go all slotted. The drill rotors at road course temps, will spider crack on you in no time.


And the last one if your driving the car to the edge on road course, rebuild the J56 calipers with better pistons that will take the higher heat, and high temp piston seals and boots before you melt the oem ones..