You should only have copper washers per original factory replacement, it would take 2 washers each and additional 1 washer at line connection where pump joins filter,5 total, if you bought aftermarket washer you should be able to use those, some pumps may come without check valves in pumps, then you would use a smaller washer at check valve to pump connection 1 for each pump check valve 2 total, grand total of 7 washers
5 big 2 small