part 1 rd28 gq pump disassembly upgrading from a 11mm to 12mm
not the best video but trying to get it apart with the time i got on it part2 ill show use how you can use the gu pump using the 11mm plunger rotor head of it so you can use it on the gq pump to upgrade from a 9mm to 11mm its a good mod and a good upgrade 12mm rotor head https://rover.ebay.com/rover/1/705-53...