loans

What is the name of your state (only U.S. law)? Oregon

Back in 2002 I was dumb enough to co-sign on a loan for my boyfriend at the times brother. Of course he defaulted and the company came after me for payment. I was eventually garnished over $4,000. while this was happening I wrote a $150 check for a car payment, my credit union accidentally bounced the check and the finance company repossessed my car, I had no knowlegde this was happening until I went to get in the car and it was gone. The finance company told me they could do this because they could now see on my public record that I had defaulted on the other loan. Now I am being garnished for my car that was taken back in 2002, all because I co-signed for someone else. Can I sue my ex-boyfriends brother for this new garnishment?

No.

He is responsible for the original loan only. If they had to garnishee your wages that means you refused to pay the loan when the ex-brother defaulted and they sued you.

While it often doesn't make sense and sometimes seems cruel, we are responsible for mitigating our damages. That means you are responsible for lessening the damages so they don't become worse, whether you caused the damage or not.

Unless you already have, you can sue the ex brother for the first loan. You are still responsible for the second loan. Once they repoed your car, you should have contacted the finance company and tried to work out a payment plan with them. That they didn't try to work something out suggests you were more than one bounced check behind.