A lot of attention is given to collateral in the loan process.  That is because collateral is a really good selling point to the lender, but sometimes collateral is not enough.

In the case where the collateral offered is not worth much compared to the loan amount or where the lender just wants more security, collateral does not cut it.  You are going to need something more.

This is where you can offer a down payment or a co-signer.  A down payment is nice for the lender because it takes money off what you will owe them and shows a level of responsibility from your side. Large down payments can sometimes be even better then collateral.

A co-signer is extra security for the lender.  Having someone else sign the loan means there are two people the lender can rely on to get their money and usually a co signer needs excellent credit in order to qualify.

The point is that you should not go into a loan deal with just collateral to offer.  The more you have to offer the better chance you will have at getting the loan.