The Hammers have debts of £70million, half of that bank debt secured on Upton Park, and that has to be cleared when the ground is sold ahead of the move to the Olympic Stadium in 2016.
Brady, giving evidence to the House of Lords committee on Olympic and Paralympic legacy today, also insisted that the club was not getting the stadium on the cheap and that the deal was good value to the tax-payer.
The club did have a buyer in place for Upton Park but that fell through due to the delays in the deal to be Olympic Stadium stadium tenants, and Brady expects income projections from the sale to be down 50 per cent on 2010 due to the sluggish property market.
Brady added she did not expect the sale would cover much more than the lump sum the club will have to pay to the London Legacy Development Corporation (LLDC) to move to the Olympic venue.
She said: "We did have a tentative deal [for Upton Park] but that fell away. We hope the money generated from the sale of Upton Park will be enough to fulfil our commitment and to help pay off some of our bank debt.
"When we bought the club and took on more than £100million of debt that was guaranteed on the ground. We have to pay off all our bank debt to move, we can't take the debt with us.
"If there is any excess [from Upton Park sale] it will meet some of that debt but I don't expect there will be."