Hello, What is it telling me when a zerk fitting doesnt accept grease? If I push the ball bearing, it moves smoothly. However, when I put the coupler on (lincoln coupler on lincoln hose and lincoln pistol-grip gun), the grease all goes around the outside of the fitting, and nothing goes in. On some itworks perfectly, on others, it does this... Would this be a sign of an overgreased part? I have the coupler on perfectly straight - checked that. Thanks!