the impeller from my waterpump (3 1/2 litre) is loose on the spindle, you cas easily take it off.
Is this normal? or is there a way to fix it?
It’s not meant to be driven by an interference fit the slot engages on the tangs on impellor and drive dog. It is intended that as the carbon seal wears it can slide back. It shouldn’t flop around but should be movable. New rebuild kits are available from Alan Gibbins in UK. These are excellent and better than places that will have a go at modifying it.