dguy

Muffler repair

5 posts in this topic

G'day,

 

Does anyone happen to know what type(s) of metal make up the joint between the muffler's flex pipe and the rigid section just down stream of the manifold flange?

 

At ~90,000km the flex pipe on ours is failing just a bit down stream from the manifold flange.  It is no longer affixed to the rigid portion of the pipe, and it can slide back & forth a ways without coming completely free.  The resulting noise is not unreasonable (yet), but the failure is allowing the muffler to swing in the hangers and it's slowly bashing a divot out of the rear skirt.  I have half a mind to try to tack weld the two sections back together rather than dropping half a grand on a new assembly, but I have no idea what type of wire I would need to use.

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For what it's worth I recently cut out the flex pipe on my 451, and replaced it with a generic flex pipe section from Canadian Tire. It was $45. I used a TIG and mild steel welding rod (not sure which alloy to be honest, but nothing special). I replaced the gasket at the flange as well, and to do so, ended up cutting the bolts and then shearing the welded nuts off the backside with an air chisel. I replaced with generic bolts for easy future disassembly if needed.

In any case, while welding it all up, I didn't notice the OEM steel to have any particularly different characteristics as compared to the new flex pipe.

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Thanks, a successful weld with mild steel is reassuring.  On the assumption that the pipes are mostly T304 stainless I was looking at some dual shield flux core wire, but I have only seen it listed in 25lb spools so far and those are approaching the cost of a replacement muffler!

 

I'll see about having a go at tacking the slipping pipe back in to place next weekend, and add replacing it to my to-do list.  I have to deal with what looks like two sprag clutch replacements on our bikes so if I can band-aid the Smart for the time being I will.

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I ended up going the whole nine yards, as after I got under the car I found that the damage to the flex pipe had worsened since my last look, plus it would have been a bugger to get the welding gun up near the top end of the pipe with all components still in the car.

 

Mild steel flux core wire appears to have fused with both the new flex pipe and the OEM steel nicely.

 

I will say one thing, which is that if I ever have deal with the cat-to-muffler flange bolts again I am going to remove more body panels and the bumper bar.  Fitting my hands and a couple of wrenches up in there (from below) to re-attach the system was a "joy" like no other.

2017-09-17 Muffler flex pipe repair 06.jpg

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