AU Fairlane Brake Master Cylinder

[CONGO MILLENNIUM]

I recently replaced the brake master cylinder on my AU Fairlane with one I purchased from a local wrecker. He asked me if my car has cruise control and anti locking brakes? I told him the make year model etc so he sold me a used replacement. On installation I siphoned out the old fluid and removed it from the vehicle. While installing the replacement I noticed there was three brake fluid pipes which had all been cut off just below the flare nuts with pliers or small bolt cutters as all three were pinched shut. My original unit only has two pipes with the third hole below blanked of with a tapered end bolt.
So why has the replacement unit have three pipes and the original two pipes?
Any way I installed it with the bottom hole blanked off with the bolt.
After bleeding the brakes I took it for a test drive from the beginning the brake pedal felt higher and progressively getting harder to a stage where the rear brakes were beginning to drag. So I pulled over to notice the rear brakes were extremely hot. When I drove away it required more power to get going I also noticed the cruise control would not set. By the time I was almost home it appeared to free up and the cruise was working again. Next day all was normal upon leaving home after driving approx 15 klms the brakes seized up again. In fact after stopping I couldn't move forward or back after waiting some time for the brakes to cool I eventually arrived home. So I checked the parking brake nothing was binding so I put the old master cylinder back on and the brake dragging has stopped. The numbers stamped on the end of the cylinder did not match also the piston in my original is a blue green colour the replacement piston is silver.
Has anyone had this problem or now any thing about these master cylinders.