Grinding rear disc brake
Hi - After a very hard mtb session, my brand new, shop-installed SRAM Level hydraulic disc brakes started grinding in the rear. This is taking place ONLY under braking, it's quiet when not braking.
The sound is like a vibrating grinding noise, kind of like the pads are grabbing each individual hole in the rotor.
Is it possible the rotor/pads became contaminated?
The only two things I can think of is:
1) I had the thru-axles out this weekend and I lightly greased the threads before reinstalling to prevent seizure. It's not probably but I guess possible some stray grease contacted the rotor
2) My ride this AM was very technical and I took some rocky lines quicker than normal, I actually bent my front rim a little when I hit a small rock I didn't see, in the trail between two TTFs. When I stopped, I noticed my tires lost a little sealant, I suppose it's possible some sealant fount the rotor?
Thanks guys!