I have some more wheel cylinder part numbers that will be added to the next Alternative Parts List update, they may be recognised in the USA? Mintex MWC 155, QH BWC3238, Unipart GWC1715. One other thing you should certainly consider doing "while the wheel is out" is to replace the rear wheel bearings with some SKF Explorer 6205-2RSH items, the original ones fail frequently. For information, the brake shoes are different thickness from new, many people think that one has stuck and worn away.
There is a whole article in this months Morgan Three Wheeler Clubs "Bulletin" magazine about things you should plan to do when the rear wheel is out. It is a bit of a job to remove and refit so you don't want to be doing it any more than is necessary. If you are not a MTWC member I can email you a copy of the article if you PM me.
