dguy

Muffler repair

13 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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28,000km later, color me unimpressed.  :huh:  The protective braid on the replacement flex pipe has fully rotted away, and the inner pipe has cracked just above where it transitions to the muffler's rigid pipe.

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Posted (edited) · Report post

There is a huge difference between an expensive flex joint and a cheaper knock off.....been there done that!  The cheap one is pure shit, excuse my french!  Spend for a good expensive flex and it'll serve you well....too late now but.....

Edited by Willys

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Define "cheap".  :)

The flex pipe which just failed was from CTC, and in the $40 range if my memory is working.

I replaced it with a pipe from NAPA on the weekend, which appears to be a re-branded Walker part.  Less expensive than its CTC counterpart, slightly different construction.  Only time will tell...

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Cheap as in build quality, name brand items usually are better than CTC, but we all keep buying from CTC .....don't ask me why, I'm one also! DOH...!


I was at a muffler shop geting something else done and I saw flex pipes and asked about them and how much. They were expensive in price but also looked to be far better made than the ones you see on the shelf at CTC.  They said it's up to you, you either get it done right or come back in less than a year and get it done again. They sold both versions and sold the better ones far more than the cheaper versions he said. He also said he made out far better by selling the cheap ones, but most after seeing the difference spent the money for the better constructed version. It looked like the strands were tighter wound and the whole thing was stiffer.   But if you didn't know one from another you wouldn't  tell after installed.

 

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Hi dguy

I just saw this post and have the same problem with my muffler.

Looking at the picture of your repair I was wondering if the pieces on either end of the flex pipe (look like cups) are purchased with the pipe or if you have to buy them separate.

I would like to try the same repair for mine.

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The cups which you are referring to are part of the flex pipe.  Shapes & sizes vary, but I have never before seen a flex pipe which isn't sold in this format:

 

 

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I have seen them with tighter cups so to speak.....pressed tighter onto the weave.

 

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