I took off my two rear mufflers, however the bolts for the flanges are extremely rusted and damaged. Does anyone know the part number or where I can get new ones online?

 

You don't give a year/model but drop your VIN into this site to get diagrams and part numbers.
http://www.japan-parts.eu/

 

Just find an ACE hardware (or similar), they have a variety of metric thread bolts in stainless.

 

Make sure to replace the muffler bearings too . As stated, best to go to a local hardware store and match them up.

 

You can find a variety of generic exhaust nuts and bolts at most Auto Parts stores. They have spring loaded nuts and bolts that won’t back out over time and they’re treated to withstand high temperatures. Just take your old ones in with so you can match up the right size