DIY Flex Pipe Replacement

[stickman007]

7000km into my new 2013 ForTwo, the flex pipe went...It has 60k on the odometer now. Overnight it became very loud, surprised that it went that quickly.

 

I knew there was a repair guide somewhere, but most either here on CsC or SCoA were vague. Here's what I did:

 

1) Flex Pipe Dynomax 41792 (rebranded Walker) from Amazon - $23.15

2) A short 1.75" extension/adaptor pipe as the flex pipe was a bit short - around $7, lost the receipt so I don't remember

 

I had to cut the old pipe off. I use a zip disc and cut along the weld - when done properly, the old pipe will actually come off revealing the base pipe.

 

Removed the old pipe and cleaned up the mating surfaces with a wired-wheel. It lines up nicely.

 

Tack welded. The extension had to be cut slightly to shorten. Only 1 tack was on the extension and flex pipe as I needed to mount it on the car to make sure everything lined up - perfect, took it back down and will bring it to work to finish the welding!

 

 

 

 

 

Edited July 29, 2021 by stickman007

[stickman007]

Here's the finished product - please don't judge my horrible welding skill (or lack of skill)! The important thing is that it was CHEAP! Didn't feel like forking out $600 for an exhaust.

 

From this experience, I realized that its better in the future to make a small "jig" to make sure that the flex pipe connection will line up...any stress due to misalignment will cause the flex pipe to fail prematurely.

 

The 451 also seems to be a lot harder to work on than my 450...maybe its still new to me.

 

Izzy

 

Edited July 29, 2021 by stickman007

[LooseLugNuts]

the welding looks just fine....it looks like mig with gas

 

mine always look way worse but im cheap and always use fluxcore out in the wind with awful results 

[LooseLugNuts]

one thing ive learned over the years though is to not weld in flip flops....plasma cutting is even worse lol

[Willys]

24 minutes ago, LooseLugNuts said:

one thing ive learned over the years though is to not weld in flip flops....plasma cutting is even worse lol

I'm still healing from welding an exhaust while wearing summer slip-on shoes made of some sort of mesh material.....perfectly round hole/crater left in the top of my foot!  But I also have a loonie sized scar from the same thing while wearing work boots.....a lump of molten steel fell inside the boot and burnt it's way down to the top of my foot and simply sizzled until it cooled down. I couldn't get the boot off fast enough so I simply grit my teeth and waited! Hmmmm.....not sure if I should have tried to get it out or wait...?  The scar is loonie sized and the same thing almost a crater...!   When you are a welder fitter, these things happen....it's part of life.

 

I find croc's the worst things to wear when working at anything.....slippery as goose shit and nails slide through them with ease!   I don't own a pair of crocs any more...lol.!!!

Edited July 29, 2021 by Willys

[stickman007]

LOL....yeah, I welded at work. I did install the exhaust with flip flops!

[booneylander]

I found the same about the flex pipe. Best to cut and clean both ends, install the exhaust into the mounts and support it with a jack stand to get the right angle, and then put the flex pipe in so it’s “loose” and tack it into place. That way it’s not under stress when you’re driving around later which leads to premature failure of the flex. I’ve got a video about it around here somewhere.