Replace the pad and the slipper plate as well (plate thats gouged). It either was too loose to start with or ran loose and destroyed the pad. With 6S, this is stressed enough that if you start out with anything wrong or less than new (like a worn and polished slipper plate), its going to prob fail again.
I replace the plate, pad, spring and lock nut everytime I fool with mine. I also run only 1/8 - 1/4T backed off from tight versus a full 1/2t as HPI recommends. I also use blue loctite on the shaft and give it ample time to cure before using.