MBM disc/drum Master Cylinder rebuild

[OllieDemon45]

I was having issues bleeding my new rear brakes and found my master cylinder was leaking right at the firewall. Took it off tonight and found it the seal on the
piston was damaged. Does anyone know if they make a rebuild or where i can find this seal?

 

[Dana67Dart]

If it's 1" no, if it's the next size up or down yes

 

[OllieDemon45]

If it's 1" no, if it's the next size up or down yes

MBM Master Cylinder (Disc/ Drum)

This is the one. So it's 1.125 bore.