Lenders don't generally lend based on collateral these days. Cash is king. When you borrow using collateral, you pledge the asset in question so the lender can sell it and recover their money if you default on the loan. If you don't own this property outright, the lender wouldn't be able to get their money without the other owners agreeing to sell. So it would have no value to a bank, because the asset itself is not really yours to sell.
You could sell your interest in the property to one of the other owners or someone else in order to raise cash.
Other than that, I think you'd be out of luck here