Smart Car of America Forum banner

Changing the exhaust - welded bolts?

15K views 13 replies 7 participants last post by  tgikal 
#1 ·
2008 Smart Pure

So the exhaust gave out on the Smarty so i ordered a replacement from Solo Performance.

It can in yesterday so i spend the good hour taking the old one out partially.
The exhaust was broken from the flex pipe so it was hanging with the rubber pieces on either side.

I'm having a really tough time taking the bolts out from the catalytic converter to the flex pipe. To the point i ended up rounding the bolts:frustration::frustration::frustration: I haven't taken the heat shield off so that might be adding to the trouble.

I started cutting the bolts out with the dremel & ran out of the grinding bits :frustration: So i took the car to a local shop to get a price estimate, the guy took a look at the bolts and so no wonder you're having a toughtime, these are tack welded on? WTF Is that right?

So i guess I'm back to grinding the bolt. Any ideas how to get these two bolts out....
 
#4 ·
I used some heat on the nuts (oxy-map torch) and they came right off. They are E-torx bolts which I then replaced with flange bolts (stainless) so they won't rust and use a hex head. The heat shield has to be moved to get to the bolts, I used a vise grip on them since they were so rusted and with the heat, they came right off. I was careful not to break them. Once they came loose. I used lots of penetrant on them so I could get the right bolt length and thread for the replacement ones.

I found it easier to remove the rear panel so I could work on everything easier. I do have a trailer hitch which made it harder to get to everything from underneath. I also warmed up the nuts on the back side of the heat sheild as they were quite rusty, and replaced those with flange head bolts too. You do have to remove the rear sub-bumper which uses torx screws and they can be difficult to get to.
Pictures


Panel removed


exhaust bolts Heated the welded nut side


Heat shield bolts


All back together.


ready for the rear panel
 
#5 ·
It's not unusual for some exhaust shops to replace the original hardware and tack weld things together. For an exhaust shop, cutting off the bolts with oxyacetylene is always faster than finding the right wrenches in the first place. They keep a heap of spares and replace the originals with whatever looks close enough. And since there's a mig welder always powered up within reach, might as well tack weld the nuts so they can never come loose.
 
#6 ·
All thanks for your help and the pictures. Today I took the rear panel completely off, i can see the bolt that i was grinding down. Hopefully this will make it easier to get to the bolts!

Just so i have this right on replacement hex bolts:

Cat / Exhaust bolts: M8x1.25x30mm

Does anyone know the replacement bolt for the heat shield?

Thanks again for your help.
 
#11 ·
Vvvviiiiccctoooorryyy... so i took the braveheart line and made it mine... :) :) The Solo performance sounds amazing! :) :) Quick question, i see smoke coming from the exhaust/cat connection. I did put loctite on it and not sure if that is what is burning. I used the old gasket also so I'm not sure if thats what could be causing the smoke. Thought i would ask if anyone knows.

Thanks again for your help.

Next Mod: Custom DIY valence since i took this exhaust tip is in the center. I think I've opened the flood gate on the mods.
 
#12 ·
Not sure if its a problem or the exhaust is breaking in... everytime i take the foot of the gas...i hear a creaking sound coming from the engine bay. Did i overtighten the bolts? Also i see the wings of the Solo performance are wider on one side of the rubber mounts than the other. ie: i can see 1 inch on the left side and barely see it clear on the right... I guess I'm starting to double guess if I've installed it correctly...

Any Smart Owners with aftermarket exhaust in Alexandria VA ? Maybe i can get together and show the exhaust install and see if things line up?

Thanks
 
#13 ·
i did my solo exhaust 5 years ago, it's a first gen with no "flex pipe", Midas did the install for 1 hour labor/$80, them wizards did it without knowledge of the heat shield. i'm waiting for it to fail, have the stock exhaust ready for replacement. the "cool loudness" has worn thin on me, but the cheap me is waiting for it to fail and put in the stock/quiet exhaust again.
 
#14 ·
Glad I found this thread!
Basically an identical situation for me following this guide: https://www.fq101.co.uk/how-to-guides/fortwo-451/panels/272-rear-panels
Was super helpful.
I can confirm the m8x1.25x30mm exhaust flange bolts and m6x12mm (I used m6x15mm) heat shield bolts, sizes are correct.
Picked up a new stock muffler on ebay for $320, you can get them from Mercedes for $360, the gasket is $12 on amazon.
My oxy-map torch came in handy getting those darn screws loose, and I found the rounded bolt sockets (standard set, the metric didn't go small enough) from harbor frieght useful in getting the rusty flange bolts out.
A 7mm was about perfect for the heat shield bolts, hit them with a torch until cherry red and unscrew, had to use vice grips on the one screwed into The muffler pipe.
Replaced with stainless hex head bolts, so hope I never have an issue with all that again, heck, I hope I never have to look at the exhaust again, lol.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top