We rebushed ours and had to have a few machined because the pin ate through the bushings.  The local machinist had what I think is called a portable lathe, but maybe it is called something else, and he machined the knee in place on the machine and pressed in bushings that had the same ID as factory knee.  We switched to calcium sulfonate moly grease and grease them every day or two.  **Never use moly in a ball bearing or any application that spins, only on slow moving pivots, bushings, ball joints.