Bearing in mind the aggro involved in turning it upside down, personally I'd throw it out. Once the air bladder starts losing charge, things are not likely to improve, it is after all leakage...... bin the blighter 
We occasionally used to recharge expansion vessels. Invariably, even though we would explain that the result would not be permanent, a customer would ring back between 1 and 51 weeks later and demand a new one free of charge
. So now we always replace.
We occasionally used to recharge expansion vessels. Invariably, even though we would explain that the result would not be permanent, a customer would ring back between 1 and 51 weeks later and demand a new one free of charge
. So now we always replace.
