I use a Morse taper in the tailstock with a 3/8-24 male thread that points toward the chuck, which is normally used to mount a drill chuck. Then I make a mandrel about 2" long that threads onto the taper that is a snug slip fit into the bore of the cylinder. This fixture keeps the cylinder bore aligned with the lathe ways. I use a fixture that bolts onto the mounting holes of the cylinder- - - -a piece of angle iron or flat stock welded to a piece of pipe that fits into the 4 jaw chuck. Once everything is rough-aligned, I use the last word dial indicator to do any final centering of the cylinder bore- - - -which is usually not necessary.

www.ebay.com/itm/177562654305?_

The centering device can be swapped to any diameter and/or length needed to fit master cylinders or wheel cylinders of any size. I just sent you a private message. Click on the flashing envelope icon at the top of any page.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!