Brake Master cyclinder options
 

I have a 85fb with rear discs, my master cyclinder is shot seals are let fluid through is there an upgrade master i could fit easliy? Im happy to a direct replacement but since its failed is there anither option? I thinknive read that a certain 929 one will fit??

Any ideas or leads would be awesome cheers guys

if you are looking for a direct replacement...rock auto has some

See the thread "FC Master Cylinder in FB". It touches on the 929 option, with a link to an even older thread specifically about a 929 MC conversion.

But more importantly, what type of improvement are you looking for? A 929MC has larger bores, which would increase the pedal pressure required to get the same amount of deceleration. Unless you're trying to correct a specific problem, a direct replacement is probably your best bet.