With that in mind, I would get new air valves because the ones you have are obsolete and probably will cause trouble if they are not already bad. The schematics from Bendix will work with your wedge brakes. The system you have now does not have the feature to limit braking power. All trucks of the 60's were a nightmare to bobtail even on wet pavement. But we did it because nothing better was available. The newer systems restrict braking power when you bobtail to prevent over braking. Also the synflex lines are a must. Copper lines rub holes and crack. I carried a butane torch and acid core solder in my tool box. I don't recommend steel braid or Aeroquip either. It is fine in airplanes, but water gets in the steel and it rusts. If your fifth wheel trailer has electric brakes, all you need is a brake controller like I have on the dash of my pickup. If it has air, you will be equipped for it.
