Brakes and parking brake questions

Ok, I obtained a T after my father passed away. Before he went into the hospital, I helped him swap out the master cylinder as he was having trouble with the pedal going away. It has a mid 70's Ford Maverick two chamber master cylinder, disk brakes on the front and drums on the rear. I bled the brakes in many different ways and never could get a decent pedal. I didn't see any leaks anywhere. I took apart the proportioning valve. It does not have any logos or name on it. The o-ring in the bottom had a slight tear. I replaced that and was able to bleed the brakes. The weird part is the proportioning valve is on the front lines going to the disk brakes. I'm guessing they had trouble with the front locking up and put the valve in. I have tried to "test" the brakes but haven't had anything lock up yet. Guess I'm just too chicken to jab them that hard.

The T also has a parking brake on the back end of the drive shaft. It was working well when I got the car. Now, not so much. It has a manual lever mounted across the floor. That levers a cylinder of some type with a white/clearish line going to the brake cylinder on the caliper, mounted to the rear. The white line reminds me of the line that you use on an oil pressure gauge. I see no reservoir or anyway to "bleed" this system. Any idea how to maintain this type of system? All the ones I see online use a cable to the caliper to activate the brakes. I haven't found one with the white-ish line going to the caliper. Ideas? References? Tips? I can't post pics yet as I'm too new here.

 

https://www.speedwaymotors.com/Pinion-Mounted-9-Inch-Ford-Emergency-Brake,44784.html

In some States the hydraulic system would not pass inspection that Total Performance use to sell. So go with the manual.

 

This one is not required to be inspected here.

 

Could be a go-cart calliper. Its what I used on mine all be it with a cable. I did look at the hydraulic ones but they were 3 times the price.