as described above it will thus be seen that during normal operation of the pump 2 the required amount of filtered clean fuel passes along the conduits 22 24 to lubricate the journals 10 the pump 2 is so designed that in the event that the rotors 20 or 26 should seize and cease to rotate the pump 2 can still operate to the extent that the gears 6 8 will still be in operation and the journals 10 will still receive some lubrication although this lubrication will be effected by dirty fuel this dirty fuel will however enable the pump 2 to continue to operate for a short period of time without undue wear occuring in the journals 10 when the rotors 20 or 26 cease to rotate the shear section 44 will shear and so the drive shaft 14 will no longer drive the rotors 20 26 the rotors 20 26 will stay stationery about the rotating drive shaft 14 the drive shaft 14 will however still continue to rotate the gears 6 8 via the permanant connection at the position 12 to the gear 6 when the rotors 20 26 cease to rotate dirty fuel in the conduit 46 can pass from conduit 48 in the direction of conduit 22 and along conduit 24 to the journals 10 the passage of fuel in this direction is assisted by the fact that the orifice 52.