I've had mine come off and not even be able to even push it back on hot. The tube would have a little bit of oil in it and it would swell the rubber and seal it tight in the tube creating pressure when hot and it would turn into a syringe pushing it off. Didn't matter how tight it was on the plug. Had to let it cool off and use a rag with a long screwdriver to get oil cleaned out of tube. Darn hemorrhoid's! Lol Dayclona's trick seems like a good idea. For those of you new to hemi wires #7 is the only one that doesn't have a plastic extension and is rubber to be able to bend it past the master cylinder.