A common rookie mistake (and even experienced mechanic mistake) is over-greasing the track pins and bushings. The goal is to purge old, dirty grease out of the joint and replace it with fresh grease. However, if the zerk fitting is plugged, or if the machine is too cold, the internal pressure in the sealed track joint can skyrocket.
When that pressure exceeds the mechanical limit of the double-lip seals, the seal will be blown out of its groove completely. The result is a "Grease Hernia"-a massive, sausage-sized tube of lubricant that bursts out from between the track link and the bushing.
Once this happens, the joint is ruined. There is no longer a seal; water, mud, and sand will enter the dry bushing, and the joint will wear out in a matter of weeks. Furthermore, that grease hernia catches on the track carrier rollers, tearing them off. The rule of thumb is simple: purge grease until you see fresh oil, then stop. If the gun gets hard, do not pump harder. Find the blockage, or you will herniate the track joint.
