I don't think anyone asked but, do you have a stock 1951, 3100 rearend in that truck???? I'd agree 100% with Bill those type of connections wouldn't be on any wheel cylinder that would fit that model truck. The bubble flare is just the first part of the double flare before the final fold. I use an English flaring tool that makes either the bubble flare or the standard double flare. Same set of dies.
Denny Graham
Sandwich, IL