The Official: DIY OEM M3 Rear Conversion- Sedan

Originally Posted by cd330

wow, that looks really good. When I mounted the brackets to the original screws and mounting points, my bumper sat out about an inch from the body. I will need to shave the screws off from the body and remount the brack closer in to the body. Then push the bumper shocks in. I heard an inch is good. I know you measured about an 1.25" short. Let me know how that works out.

Yeah I shaved the screws off too here's pics of my finished side bracket.



You can see here the flap that I had to shave down aswell



Remounted with self tapping screws


Backside shot of mounted bracket


And here's what I did with the bolts. I went to home depot and bought 2 zinc plated 3/8 x 4 inch bolts and 2 3/8 washers. Much easier To handle than the t50 bolts with a less chance of stripping.


As for the bumper shocks, can I hammer them in? Or will that set off my airbags? How could I go about doing It without welding them ?

So you didn't shave the brackets down? You just pushed them in as far up to the side body as possible and remounted them?

Good alternative to the bumper bolts.

Also, in re: to the bumper shocks... I've heard two things without having to reweld.

1.) Take the shock off and look down the back side of the tube. There is a plastic cover inside the tube. You could drill a hole in that to relieve the pressure, push the shock in, then put a screw in the hole and cover it up to prevent leaking.

2.) E30 bumper mod. Slowly back into a wall (using a 2x4 between the wall and the shock). It will slowly compress like a 5 mph collision, but should not set off the airbags.

Originally Posted by cd330

So you didn't shave the brackets down? You just pushed them in as far up to the side body as possible and remounted them?

Good alternative to the bumper bolts.

Also, in re: to the bumper shocks... I've heard two things without having to reweld.

1.) Take the shock off and look down the back side of the tube. There is a plastic cover inside the tube. You could drill a hole in that to relieve the pressure, push the shock in, then put a screw in the hole and cover it up to prevent leaking.

2.) E30 bumper mod. Slowly back into a wall (using a 2x4 between the wall and the shock). It will slowly compress like a 5 mph collision, but should not set off the airbags.

Hmm I might do #1

But yeah I did shave down the bracket. You only need to shave the corner tho where the farthest hole is.

Heres what I did to the drivers side flap.





Reasoning for this has nothing to do with the bracket but for the bumper. Since the bumper is pulled in, the sliders on the bumper hit this flap and don't allow the bumper so sit right at the fender. By cutting this out it allows the bumper to travel as u can see here.

Here's what u have to cut on the brackets

Great, looks like more cutting for me then. I didn't take off the wheel well lining, I was just concentrated on the brackets and everything else....

Here's the bracket mounted and bumper finally mounted. Def gonna need to shorten those bumper shocks

Nice work.... you are def helping me out , just get those shocks shortened and it will be on point.

i didnt realize fitting the rear bumper was so difficult

Originally Posted by 330i ZHP

i didnt realize fitting the rear bumper was so difficult

Yep, that's why a lot of people don't do it. If you want it to look oem, a lot of modification is required.

Originally Posted by cd330

Yep, that's why a lot of people don't do it. If you want it to look oem, a lot of modification is required.

yeah bro, ive gotten so frustrated at points (especially with the seized bolt) that i just wanted to give up and kick my car off the jack stands.

Its definitly not for the average DIY'er. You need the right tools, time, patience and experience with retrofitting. Also if your broke, dont be attempting this. I spent a good amount of money on just tools (dremel attachments, drill bits, screws, bolts and new brackets.) just to make it work.

lookin good dude! the bracket route is time-consuming but in the end is the proper way to do it. my zip-tie attempt worked great for me. shorten those bumper shocks and it will be fukin perfect!

I must say, sedans with M3 bumpers look sooooo much better than coupes. Don't get me wrong, I love mine but all m3s are coupes and all m3s have that bumper. Mad props

Originally Posted by codyfunk

I must say, sedans with M3 bumpers look sooooo much better than coupes. Don't get me wrong, I love mine but all m3s are coupes and all m3s have that bumper. Mad props

Thanks guys, I'll post better pics once my diffuser is painted and I route my exhaust

I didn't realize how much wider the sedans are than the coupes

Originally Posted by codyfunk

I didn't realize how much wider the sedans are than the coupes

They aren't, the M3's are wider and the fender flares sit out more. Hence, modifying the bumper brackets and pulling them in closer to the body on the sedans. I should have taken a pic yesterday to show you.

Pretty much if you mounted the brackets on the sedan in their original mounting points, the M3 rear sits about an inch out from the body on the sides and 1.25" short at where it meets the wheel well.

Originally Posted by codyfunk

I didn't realize how much wider the sedans are than the coupes

I think u are mistaken, the coupes are definitely wider than the sedan

Originally Posted by cd330

They aren't, the M3's are wider and the fender flares sit out more. Hence, modifying the bumper brackets and pulling them in closer to the body on the sedans. I should have taken a pic yesterday to show you.

Pretty much if you mounted the brackets on the sedan in their original mounting points, the M3 rear sits about an inch out from the body on the sides and 1.25" short at where it meets the wheel well.

Yes can believe I didn't take a pic of that! :facepalm.

I actually think I'm gonna drill my shocks. Seems like a bunch of people do it on the e30s

Originally Posted by AW330

Yes can believe I didn't take a pic of that! :facepalm.

I actually think I'm gonna drill my shocks. Seems like a bunch of people do it on the e30s

I will take a pic for sh1ts and giggles the next time I work on it for "the thread" (going out of town this weekend, won't work on it again for a week or two.

I haven't done a lot of reading on it, but are they doing what I talked about earlier? bleeding the shock a little bit, compressing and then sealing back up?

Originally Posted by cd330

I will take a pic for sh1ts and giggles the next time I work on it for "the thread" (going out of town this weekend, won't work on it again for a week or two.

I haven't done a lot of reading on it, but are they doing what I talked about earlier? bleeding the shock a little bit, compressing and then sealing back up?

Yep that's exactly what they are doing

have you decided how you are going to do that? Are you going to drill into the actual shock then try to pound it in (with a hammer, off the car of course) ? Are you going to drill the plastic cap on the back side inside the shock?

Originally Posted by cd330

have you decided how you are going to do that? Are you going to drill into the actual shock then try to pound it in (with a hammer, off the car of course) ? Are you going to drill the plastic cap on the back side inside the shock?

No havnt decided yet, still gotta do some more research on it. Every diy ive looked at they have drilled into the actual shock itself. So that may be have to do. But the shocks def need to be shortened the Mis alignment on the fenders is driving me nuts