After experiencing a great deal of trouble with the dual master cylinder
in my 1953 XK120, I decided to convert to a single system and purchased
a new Lockheed single master cylinder (Item GR-28708 in XKs Unlimited
catalog). Now that I have changed my mind, I have a new, in-the-box,
Lockheed single master cylinder that fits either early 120s or a 140.
If anyone is interested in purchasing it, I am open to an offer.