Hi, I had exactly the same problem. I went to a vintage auto supply company who specialise in rubber seals. I bought a 1 inch square of very hard rubber, cut it so size and slipped it into the holder on the bottom of the pipe. Not original, no-one knows, saves the pipe, I never think about it any more. Unless you want to spend $30 for an OEM part, if you can find one, I certainly didn't.