Bentley may describe a test, or likely another of "us" here will proffer a suggested method.
This is a good description of the process of replacing the MC.
http://www.vanagonauts.com/Brake-master-cyclinder190.htm
Bentley 30.2

bob
On Nov 9, 2011, at 8:18 PM, Jeff Lincoln wrote:

> Makes sense Bob - is there a way to test the MC? It's easy enough to swap out but would like to check it if there is a way to do so.
> 
>  
> -- 
> Thanks,
> 
> Jeff
> '85 GL (Gertie)
> '90 Carat (Grover - the noble parts donor) 
> '78 Bus (Melissa) Patty's Bus