The Caliper is similar to that of the rather splendid Zip restored by Silverstripes viewtopic.php?f=21&t=2688
My caliper differs in that it only has one pipe feeding hydraulic fluid, unlike the two pipes on Silverstripes Kart.
I have no pads with the caliper so I assume that it will take these viewtopic.php?f=195&t=2667
I also figure that the pad release mechanism is a mechanical, bolt through sleeve, spring and caliper body into back of brake pad. However, there are some additional bolts that screw into and through the caliper body that I figure could exist to adjust the gap between pad and disc as the pad wears by providing and adjustable pad stop.
Have I figured it right cos I don't have the benefit of having raced when I was young, and my lads Tonykart self adjusting caliper makes the Zip item look like something I might have knocked up in a metalwork lesson at school

If I am right, any idea of length of bolts, springs and sleeves and which ones might do the job