411 brake problem

[Kevin H]

After several months of not being driven, or even started, my 411 seems to have lost it's brakes.

Other than the return spring there is absolutely no resistance when pressing the brake pedal, even by hand.

It was fine a few months earlier when I last drove the car.

The brake fluid reservoir was quite low, but I cannot see any sign of leakage from either the master or slave cylinders. To be honest I can't remember the last time I checked the brake fluid level so it could have been like that for quite a while.

The only thing I can think of that could explain the break fluid loss is that it's going into one of the vacuum boosters, but I don't think that would explain the zero resistance on the brake pedal, or would it?

I guess I'm going to have to remove the master cylinder to investigate that. Thankfully it's a very easy job in the 411.

How can I tell if one of the boosters have failed without removing it from the car?

Any other suggestions welcome