So what exactly does a Chapter 13 do with regard to debt that is co-signed by someone who did not file bankruptcy? What about debt that survives a bankruptcy such as many (but not all) student loans?
First off, a co-debtor stay is imposed immediately when a Chapter 13 is filed. That means any collection action, including phone calls, are supposed to cease immediately for the co-borrower even though he or she did not file their own bankruptcy.
Second, a Chapter 13 bankruptcy plan payments appear to toll the statute of limitations whether or not the trustee makes the payments once a creditor files its proof of claim that survives any debtor objections.
Reboot Your Life: Tampa Student Loan and Bankruptcy Attorney Blog


