I am trying to determine weather I have a bad master cylinder or brake booster....I push on the pedal while the Rover is running and I hear a hissing sound. I have replaced the pads with Akonobo pads. The system was bled properly about a year ago.
So how can I determine if I have a bad booster or master cylinder or both?

My feeling is since the pedal is firm the master cylinder is good. Basically no leaking past the seals. The hissing seems I would have a bad booster and weak stopping would confirm that since I have would not be getting assist from the booster.

Any pro brake advise would be appreciated.

 

I think weird noises associated with the master cyl are typically the booster. Years ago I swapped a booster that would make a weird moaning sound.

 

a hissing would indicate a leak in the booster as there is no vacuum at the master

 

I just replaced a Booster on a Chevy. The hissing sound was most pronounced by the brake pedal inside the cab, but you can hear it on the outside too, depends where the leak is. If your description is accurate, it definately sounds like the booster is leaking air. Try to get close and find exactly where the sound is coming from. Maybe you'll luck out and find it to be the hose or connection.