Catalytic converter bolts snapped - Plan A, B, or C?

[Grizz]

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

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.

 

[smokin'joe]

mighty fine collection of corroded components.
recommend dissasembly by any means, and persevere with breaking/stripping fasteners until you replace with new (with copper-cote on all disassembly threads.

euro import , by chance ? bet there is other corrosion issues looking at the state of exhaust

[Nominal]

E's in the UK so probably common?

Are you just trying to re-attached the exhaust? Maybe get a short piece of flexi exhaust (or another ball joint) off something else and weld it to the cat then shorten the exhaust pipe a bit. Then you wouldn't have to deal with the rusted shit.

[tortron]

Throw the cat in the bin because at that age its not doing any thing any more, is there anything in it? 

Fit straight pipe 

Or turbo manifold

And then a flexy joint

 

 I'd cut those studs off, drill them out and replace with bolts. Tack the heads in place with mig (if the rest of the flange doesn't fall apart) 

[Nominal]

Don't bin cat, it's worth money for scrap.

[GuyWithAviators]

8 hours ago, Grizz said:

And “work” prior to me seeing it. 

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

 

Looks like someone chewed on it with one of these. 

[kws]

I've done option A before. If you use long bolts you can replicate that spring setup again, just with bolts instead of studs. I think you need those springs as that's a kind of flexi joint. 

[yoeddynz]

On 12/08/2022 at 14:44, kws said:

kind of flexi joint. 

Yeah it's a neat design (when the bits ain't corroded to that level)  and yeah - bolts instead of studs are fine but they need to be just the right length of clear shank so when done up tight they protrude the same amount as the original studs.  It's purely the tension on those springs that should be holding it all together. 

How have you got on with this @Grizz?  Or are you dead from excessive swear laden sweating in the heatwave going on there? 

[Grizz]

1 hour ago, yoeddynz said:

Yeah it's a neat design (when the bits ain't corroded to that level)  and yeah - bolts instead of studs are fine but they need to be just the right length of clear shank so when done up tight they protrude the same amount as the original studs.  It's purely the tension on those springs that should be holding it all together. 

How have you got on with this @Grizz?  Or are you dead from excessive swear laden sweating in the heatwave going on there? 

There you go.

 

So not a lot of swearing……… YET.

[Grizz]

I used a Vax wet vacuum cleaner to clean the seats.

 

Front seats after the first cleaning relinquished a lot of dirt, settled in the bucket.

 

 

 

Yesterday afternoon I got the grinder in, cut wheat was left of the broken bolts off, followed by a slow grinding back with my favourite tool.

 

 

Need to replace these.

 

 

Grinding back.

 

 

So before I get it in the neck, both sides had been threaded in, one into a blind casting, the other, through the casting and into a fixed nut as far as I can see. 
 

But I think a couple of long M8 bolts welded in place should do the job.

 

if not, refrigerator time. 
 

[Valiant]

You need some heat in that flange (lol)

Weld a couple of nuts onto those studs, get the flange red hot and keep it red hot while you start working the studs out.

 

Edit.

Scratch that.

[yoeddynz]

22 hours ago, Valiant said:

Weld a couple of nuts onto those studs

I see where you were going with that - until that pesky grizz chopped them off. 

He could weld a couple of studs onto those now ground down stubs. 

Then he can weld some nuts onto the studs.

[Valiant]

I'd plug weld a nut onto those nubs and be about %60 confident they'd come out first time.

[yoeddynz]

I did exactly that on some screws the other day. Worked a treat. 

[Grizz]

Ready to Rock n Roll or curl up and Die.

 

The bolts need plating removed.

 

Not going to try remove the studs.