Classic/Antique Car Repair: 1940 Plymouth master cylinder., hemmings motor news, diameter wire

Question
Hello:
I have three questions regarding a 1940 Plymouth Deluxe P10.
1. The master cylinder has 2 ports, a main port and a relief port. It appears the port is much larger than the relief port. I can pass a very small diameter wire through the relief port but the main port will accept a much larger wire.
2. Can you tell me where I could get a rebuild kit for this master cylinder?
3. Wher driving the car and using the brakes, the rear brakes are fine but the fronl brakes do not release after using them several times and the only way to get them to release is to let the car sit for a few hours. Could this be due to the relief port being plugged? It appeared to be when I initially tried to pass a wire thriugh it.
Thanks so much for your time. I really appreciate it.
Carl

Answer
If the car is equipped with the original master cylinder all four brakes are connected to the one master cylinder piston. Meaning that a problem in the master cylinder would effect all 4 brakes, not just one end of the car. The problem that you describe could be caused by a defective flex hydraulic hose at one or both of the front wheels. This allows pressure from the cylinder to activate the front brakes but released the fluid flows slowly back to the cylinder taking some time to release one or both of the front brakes. To fond a master cylinder rebuild kit latch on to a copy of Hemmings Motor News, the old cars classified bibl, or check www.hemmings.com.
Brad