Opened up ,steel paste sitting at the bottom.One side of the brake disc completely worn off on the piston side.
I know what caused it ,,,,the reactive pins .
We made new ones at engineering,not knowing that the factory ones have a plunger in the core .Know it now from the manual and parts diagram.
Pressure from the piston chewed everything up .Need new pistons to .Expensive lesson.
Part supplier recommendation side would be welcome .I have emailed broken tractor,there web page blocks me from SA