The only problem was that the rubber is quite specific in its properties as its soft to seal, but also tough so it does not collapse. Fuel pipe was too hard and others were just out one way or another.
So cutting the center out of an old Sud ht lead cap was just soft enough and so far has worked very well. I hate dragging round a compressor and all the noise when a good pump gives a bit of exercise and efficiently sorts that one annoying tyre with the slow leak.
