DIY: Axle-Back Exhaust Removal

Great writeup. This will make installing the Remus exhaust a lot easier...
cheers

Can't wait to use this to install the exhaust that's on the way!

This was such an easy upgrade thanks to this writeup. Not intimidating at all! I didn't end up removing any bottom covers past the large aluminum plate. The last 2 plate bolts were under a plastic cover but it was flexible enough to get my hand and a wrench in there. I was done in about 90 minutes.

Best part? No leftover bolts! Haha

The Active Autowerke exhaust sounds amazing and the BPMSport stage 2 tune took care of the CEL that was thrown about a week later.

Thanks for the DIY!

Great ... Just what I needed.

Need help. In pictures 14 and 15 showing the rear bracket, what size screw heads are on there? It's sort of a reverse Torx or something. I can't get it off and need more detail. I tried with a 12 point 5/16" and 8mm and it's crazy tight and started stripping. Anyone know EXACTLY what the bolt head is?

You're right, it's a reverse Torx. Your local auto parts store will have them. I think it was a 16? I can't be sure, but yeah don't try any other socket other than the correct Torx. You'll round it off.

For reference, I've determined it's an E10 socket.

Header back is a whole new story. I took off a system on an e92 with ease and then on my car an e90 the undertray wouldnt come off?!

Does anyone know the part number for those red urethane hangers by the secondary cats (same ones that are up front)? Can't find a part number for the life of me.

Thanks for this write up! Helped me a ton. I do have an E93 and I had to unscrew the big middle bolt and the 2 smaller ones closer to the wheels to give the reinforcement brace enough flexibility to slide the exhaust out, rest is easy!

This tool will make your life easier when dealing with exhaust hangers:

http://www.amazon.com/Lisle-38350-Exhaust-Removal-Pliers/dp/B0012S9A5U/ref=sr_1_1?ie=UTF8&qid=1379446526&sr=8-1&keywords=exhaust+hanger+tool

oh wow, wish I would have known about that tool before!

For anyone interested, the part number for those red triangular hangers for the axle back portion of the exhaust is 18207544809. They were $25 a piece from my local BMW dealer. New one is on and exhaust is perfect now

4 years later, still a useful DIY.

A few notes to add based upon my first DIY stock muffler removal yesterday –

Yes, you can fit a shallow ratchet + 18 mm socket to get these.



It’s useful to have a small flathead to lift/pry the clips off of the bolts once you remove those 18 mm nuts as well. Mine were pretty snug.

The rear hanger is indeed held up by E10 reverse torx bolts. Suggest getting that specific socket (cost me $2.99).

10” extender is perfect.

I didn’t go the jack route. Instead, put some padding up at the front of the muffler, grabbed it by the tips (that’s, tips), and jostled a bit. Front section dropped down onto padding and then I lowered the muffler down slowly with man power. When I removed all of the bolts, nuts, etc. it acted like it wasn’t going anywhere. The rear side hangers with the long bolts were holding it in place quite well, actually. So I think it’s optimistic to support it with the jack, remove everything, then simply lower the jack. Not saying going that route is wrong, or won’t work, but I would have found the jack to be more in the way than anything. Maybe others have removed everything and it dropped like a rock, in which case a jack would be nice.

56” race ramps worked well. A bit more clearance at the front end of the muffler would have been nice, but no real complaints. Didn’t impede.

Hit everything with Liquid Wrench the night before, and everything came off without issue.

Whole process took about 1 hour and I’m a mechanical idiot.

Car sans mufflers is absurdly loud, especially on cold start. My DCT is in a storage unit currently and I thought it was going to collapse.

Thanks for the write up just did my exhaust last week!

So glad this DIY is here. I just finished the job and am quite happy with how easy it was. The only strange thing is I never encountered the E10 reverse torx bolt...

This DIY was a life saver. Just want to add one detail to the "It's easier to just remove all of the hangars from the car, rather than muscle the red poly bushings off of the catback while lying on your back" step. Removing those bushings is REALLY hard... unless you have WD40 (or the right tool, mentioned above). I tried for a good 30-40 minutes to get it off with leverage, bare hands, and several flat head screw drivers (like an idiot). A couple of sprays of WD40 and all the bushings pulled off with only moderate bare hand effort.

While the above posts also reference an E10 reverse torx socket, I never felt the need, as the standard (5/16", i think) socket hooked in with no problems.

Just an FYI for anyone attempting this, 2010+ models used E10 reverse torx for the rear hangers. 2008-2009 use standard nut.

C-ARchitect wrote

Just an FYI for anyone attempting this, 2010+ models used E10 reverse torx for the rear hangers. 2008-2009 use standard nut.

E10 for me on both my '08 and '09.

FormulaMMM wrote

E10 for me on both my '08 and '09.

I stand corrected, perhaps E10 reverse torx has been an E90 thing from the start.

C-ARchitect wrote

I stand corrected, perhaps E10 reverse torx has been an E90 thing from the start.

No problem. If M engineers were a courteous crew, it would have been a standard nut, but they enjoy torturing DIY'ers.

FormulaMMM wrote

No problem. If M engineers were a courteous crew, it would have been a standard nut, but they enjoy torturing DIY'ers.

I agree. This car seems to be specifically designed to be a serious PITA for anyone who tries to work on it themselves. I've owned and worked on several cars in the past, and this is the least fun to work on by a great margin.

This helped me a bunch. Thank you!