Hy VanattiWorkshop, I sent an "E" mail to American Classic, trying to find out what the original application for the master cylinder was full disc, disc/drum, or full drum, I was answered by a budding politician, they said " Trick question. If you plumb it then yes it works for all". So I sent him another "E" mail asking them if their master cylinder p/n BRO129 had built in residual pressure valves. Their answer was "Another trick question. None of them do to my knowledge. You only need them really if you are sighting the master cylinder low under the floor and the fluid will run back. We sell a 2 and a 10 valve for that." So from that I would assume (and yes I know what we do when we do that) that BRO129 would require a 10 p.s.i. residual valve in the front and rear brake circuits. I was extremely disappointed with their response, drum brake master cylinders have residual pressure valves built into them, regardless of where on the vehicle the master cylinder is mounted. Hope that helps
