I bought a GL1100 Aspy master cylinder with linked brake line fitting on Ebay. Paid an awful lot of money for it...and was very disappointed. The M/C was crusty, seized, and the ears of the circlip were broken off. I played with it for an hour or so and decided to risk cutting the circlip in half with a dremel cutoff wheel. This shouldn't harm the function when I'm done. Then how to get the stuck piston out without destroying the valve body? And then a brainstorm...(hope it doesn't turn out to be a light drizzle!)...I drilled and tapped the piston to accept a 1/4-20 threaded rod to make a slide hammer. A couple washers, a piece of pipe and presto, out comes the piston without damaging the bore.
I hope this helps someone else, cause these master cylinders are hard to find.
I hope this helps someone else, cause these master cylinders are hard to find.