A few thoughts on broken exhaust pipes.  I have had exhaust pipes crack on
me twice.  Both times at least one of the mounting brackets was broken
(first time the muffler bracket, second one of those tubular supports).
Both times I removed the broken/cracked pipes and had them welded.  It cost
$20 each time.  Another $20 for new gaskets and bolts and everything was
perfect.  Neither of the welds that I have done has broken again.  So if
your pipes are in good condition, other than the crack/break I would remove
them and have them welded.

John Brown