First:
What specifically makes you want to replace the breaker?
Next:
A breaker only uses one side of the battery wiring (probably positive). So as long as you touch only those wires, and don't touch them to antyhing else, you can't hurt anything.
Touching them to each other won't do anything bad, though if the breaker is also the power switch, then it may spark when touching them together, but wont' hurt anything. If the breaker is not also the power switch, and hte switch is off, then there won't be any problems at all even fi the two breaker wires touch each other.