Broken catalytic converter bolts - Plan A, B or C ?

I thought I would ask the question here as there is a lot of knowledge.

Based on what I see here it is a phone call away from becoming a double door refrigerator.

And making the best decision may not always be the most popular

A Small engined manifold attached catalytic converter with a pair of snapped bolt heads…….

These are meant to keep a pair of springs in place to absorb the movement of the engine, against the exhaust with a cup and ball design.

At 130k miles trying to undo them, the hapless owners managed to have both heads break off with an impact wrench, despite copious amounts of penetrating oil.

Now stuck with a pair of studs protruding from the cat, one threaded into the casting, the other seemingly bolted to a nut……….



Options seem to be:

A) To cut the studs flush, centre punch, drill out and tap new threads, add new bolts

B) To remove the manifold after dismantling half the front end and repeat “A” after snapping half the fasteners along the way, including manifold bolts.

C) Clean up the studs well, clean the catalytic converter face, make sleeves to fit over the studs with threaded ends to take new external nuts to hold the downpipe cup and then weld either Mig or Tig in position, these sleeves and return the springs, assemble the downpipe and refit the exhaust.


The evidence.







This is the general condition down under there.



And “work” prior to me seeing it.

And NO, I honestly have no idea how that was created.