After some hours of frustration with the lousy construction of the main brake cylinder mounting on my TC, I heard from Jim Shade that Phil Marino offers an improved nut for that.
The problem was that the spanner could hardly grip the old nut, because of the triangular chassis mounts.
Phil´s nut is about 2 inches long and goes beyound the triangular mountings, so that every spanner could grip it easily.
If one ever has to remove an old main brake cylinder I really can recommand that solution.
Walter