The collar was originally sealed using a thick cork gasket squeezed between 2 large washers. Doing that would naturally entail opening the ujoint ball, disassembling the u joint and dropping the torque tube to slide the parts on. The cork gasket is easy to find but the washers may be hard to find. There is a rubber O ring (National #327) that has been mentioned in these forums as a suitable substitute for the cork gasket that may work for the scenario you're thinking of trying. Cut the O ring, slip into place and use a bit of sealant where you cut it. Just a thought.
