A 1954 car would have the remote reservoir mounted on the firewall, iirc?
Getting spares for these may now be tricky, try PowerTrack Brakes, they are often the best source for our older models.
http://www.powertrackbrakes.co.uk/wcylinder.html#cylinder I would strongly recommend going to the dual circuit cylinder , unless you are a stickler for originality. Not a simple drop in replacement though, as you must make up new brakes lines to ensure the two circuits are indeed separate.
