Are these the std copper washers or the ones with a rubber seal fitted. copperones should be replaced they become hard with age and the ones wit the rubber seal can be damaged other wise check the length of the banjo bolt it could be bottoming out...Im out of any more Ideas after that
one thing i was told to do is heat up the copper washers with a blow torch before they are fitted. this will soften them and they will form a better seal. dosnt matter when they are heated they will stay softer till used
Check the copper washers and banjo bolts and looking at the photo you have over filled the master cylinder , there has to be room for the displaced fluid to expand into the master cylinder.
Has a mind full of useless s**t and isn't afraid to use it !
Make sure you have the right banjo bolt. When I fitted mine I replaced the original washers with copper ones but had the same problem. replaced banjo bolt with a slightly shorter one and all was OK