Muffler repair 92 SPN

It looks like the metal support on the muffler body got loose and rubbed up against the muffler originally. Whether the hole is just from an inadequate repair or not is hard to say. I was surprised at how little glass was used wrapping some of the joints in my muffler. But it did last 26 years... You might consider reversing the support so the end faces in and the bend faces the worn area. It might even be good to bend the support a little. If the muffler is strapped down securely you shouldn't have that issue again. 

If you take the muffler off be sure to shake it some. That was how I found out my inner baffle had come loose. My muffler is much more quiet since I fixed that too.

You really can't go wrong on this repair, because you can always add more fiberglass! I have yet to see a muffler that was not repairable.

I am planning on just filling with G-Flex from the outside and putting a little bit of mat over it after some sanding of the surrounding area.  Temporarily I put a large hose clamp around the pipe (plus zip ties since it was hard to get the clamp to the very very top of the pipe) with a piece of neoprene over the hole and this has basically cut it to a very very small dribble.  

I am posting because I am suspicious that this may have been repaired before (see pics) or that I should be otherwise concerned.  It seems odd for a hole to just open up like that and in that location...although that might be a natural stress point with engine vibrations...