leaking master ?

[Terryb]

This can be dreadfull on a trip......and expensive to replace. In most cases it won't help to carry spare seals because the leak is normaly from corrosion right where the back seal sits. Putting in new seals may not stop the leak.
Just measure your master bore size and keep a 1-2mm thick washer in your toolkit, which you can put in front of the circlip. This will move the seal off the damaged area until you can get it repaired.