Bad Brakes - Expander or Master Diaphragm?

[Clipped Cub]

Is there an easy way to tell if a mush pedal is from a failed expander tube or the diaphragm in the master? I am still trying to diagnose the right brake that went mush pedal. Pressing on the pedal does not produce a leak of fluid at the wheel. There is fluid in the master.

I'd rather not remove the seat and then remove the master and disassembling it to look at the diaphragm unless that is the only way to tell.

Craig

 

[jimrice]

 

[cubdriver2]

 

[140pilot]