Well, first check the 1 way valve and grommet on the booster first under the hood. Usually they fail first. Remove the one way and verify it only flows from the booster and not in. Check the grommet to see if it's dry rotted.
some cars when you bolt the master cylinder on it presses on the one way valve just slightly by the reservoir, like my car, preventing it from being removed easily, just unbolt the master cylinder and see if this will give you room to remove the one way valve.
Ah, i haven't looked at a stock fox booster in some time. I'm used to the larger SN95 booster.
Yes, you can unbolt the MC and pull it forward a bit without messing up anything with the brakes. The booster rod sticks out and pressed against the MC bore. Just don't turn the booster rod any and you'll be fine.
You may not need to remove however. Visually inspect and wiggle it and listen for a hiss or sign of leak. However, if the rubber grommet looked cracked, it more than likely is leaking.
i only hear the hissing inside the car under the dash. makes me think the booster is shot i guess. but i will check the grommet and valve. grommet does feel like rubber and not hard and brittle