New cylinders are still available for my truck but I am going to sleeve my parts instead. I am about to send off my master, slave and brake cylinders to be sleeved with tempered brass rather than stainless. The brass is much harder than cast aluminum and not much softer than cast iron. The hardness of stainless isn't necessary in brake systems and installation of stainless sleeves has much higher risk of breaking the castings. After removing and seeing what time and low usage does to OEM brake systems brass sleeves and quality VAT paint coatings should be the last brake components job this truck sees.
I'll second what John said!
But hang onto those old cylinders (don't throw them away) even if you do get new ones. The day will come when you can't get new ones and you'll be happy to have old ones to stainless steel sleeve. (or better yet sleeve them now)
Grigg
