I've got a tomos a3ms just changed the crank bearings and seals, one seal went in fine, but the other one is a no go. I've messed up 2 already trying to get the bloody thing in and I'm stuck. Does anyone have any good tips on getting this seal to fit? Its like trying to put a round peg in a square hole. I've used force and being extra gentle but all that happens is the seal ends up warping or the rubber round the edges comes apart.