Duncanson T/S Water ingress

I have a problem with my boat taking water,I have had 2 bolts repaired inside the centre board casing.After the repair was done, on the mooring with the keel up she takes in a few litres of water, with the keel down after 1 day she has 8" of water above the floor .
Has anybody ever had this problem or thoughts as to what is wrong please.
The boat was built 1985 .Thanks.Alan Cartwright