I've been having problems with my mks sylvans. When i bought them the bearings seemed to be too tight or dry, so I opened them up and regreased and readjusted them so they were buttery smooth. after about 10 miles, the cone on the left pedal had tightened itself against the bearings so that it would stick in one position if my foot was not clipped in. This makes it pretty much impossible to clip in my left foot when I am riding, I have to stop, stick my foot in the clip and take off. by now I have rebuilt the left pedal 4 or 5 times. it keeps tightening up no matter how much I tighten the locknut. The right pedal is fine, I only had to adjust it once. I am at my wits end. wtf is going on? Any tips or tricks?