[rt7085]

I have a 2008 E91 328xi wagon (120k Mi). My headers broke loose from section 2 due to severe corrosion of the bolts (and flanges). I think I can mend it by replacing the mounting hardware and gaskets after some cleanup of the surfaces. (I will take some advise from peeps that have done this before me.)

Its amazing how corroded this part is compared to the rest of the exhaust which is still in good order:

View post on imgur.com

I like to replace all hardware I touch. From the picture above you can see there is a corroded bracket as well. I have tried to identify the P/N in realm.com but I am at a loss as I cannot find it elsewhere in the database. Any suggestions?

View post on imgur.com

[Tunafish]

Should be this part number 18307541458
Its the non xi 328 but looks to be the same...
https://www.realoem.com/bmw/enUS/sho...88#18307541458

[Efthreeoh]

Been there and done this. You'll need to grind off the studs, then drill them out. It's a serious bitch of a job. I have a lift, and air tools, and it took me several hours using industrial twist drills (drill bits). I removed the rear of the exhaust to get it out of the way.

Doing it with the car on jack stands, will be even more difficult. My advice is take it to an exhaust shop.

[JonOhh]

This^

I struggled with mine for hours, took it to an exhaust shop, and within 30 minutes it was broken free and had all new hardware. It was very cheap too, if I remember right.

[rt7085]

I finally got around to getting this corrected. It is rusted pretty bad, worst than I estimated. Even if I cut and drill out the studs, I am afraid that the flanges are rusted out so bad that there is not enough material left for strong connection. I am trying to jury rig it with split clamps but eventually I think I need to get new exhaust section 1 and headers or have a shop weld on new flanges. Which would require the headers to come off the engine given that welding would otherwise not be possible. At that point, I should just put on a 'nice' exhaust and do it right. I love this thing and like to keep it on the road for long.

[simsima90]

It’ll be fine, take it to an exhaust shop and they’ll have the studs removed and put new gasket on.

[S65Hunter]

I have a used one if ya want it

[rt7085]

I decided to jury-rig it by combining a couple of 2-2.25 inch split clamps. I cut the studs shorter but not all the way off. This allowed me to continue to interlock the exhaust ends together and keep the new gaskets in the proper location. But short enough to allow for the split clamps to fit. Then I squeezed the ends together with the clamps as shown. A bit of a puzzle to fit them as they interfere with each other slightly and to make sure I could get a tool on the bolts as well. On one side I needed to start with slightly longer bolts to be able to get the nuts on comfortably while reaching in between the pipes. I torqued them down hard.

In the beginning one side was still leaking a bit but after I heated the system up by running the engine it seemed to settle out and be leak free.

This will hold for a while such that I can get my inspection done for one. I can now figure out what new exhaust system I may go with. I like to Supersprint systems with high flow cats but its pricey. And I am going to need a tune to keep it all in check. I may need to relocate the O2 sensors further to the back.

Worth it? Alternatives?

[Glene]

Originally Posted by JonOhh

This^

I struggled with mine for hours, took it to an exhaust shop, and within 30 minutes it was broken free and had all new hardware. It was very cheap too, if I remember right.

Trying to remove the catalyst converter in my 335XI today. The first bolt broke and the other three the nuts rounded. I am wondering if the studs can be pressed out?

[relative4]

Originally Posted by Glene

Trying to remove the catalyst converter in my 335XI today. The first bolt broke and the other three the nuts rounded. I am wondering if the studs can be pressed out?

Put the flange in a vise, heat it up, and beat out the stud with a bigass hammer.

[e90yyc]

Man I must be lucky... In preparation for dropping the exhaust to replace the driveshaft guibos and center support bearing, I figured I'd try to remove those nuts the other day when I was already under my car for something unrelated. I thought that way I'd know what kind of a day I'm in for when I go to do the job...

I took one look at them and thought surely I was f*cked, but I was astonished when they zipped right off with the impact. This is after 200k miles in a climate where the roads are heavily salted about half the year. Looking at the front of the studs, I thought the corrosion I saw was the remains of what were once threads, but after removing the nuts I saw the threading was almost entirely intact. To be fair, the nuts on mine were in better shape than OP's, but still: I needed a 13mm for two of them, a 14mm for the third, and a 15mm for the fourth...

Apparently these are copper nuts, which might explain why they came off at all. I know this doesn't help you, OP, but I thought I'd share my story in case anyone else thinks they're screwed and just starts drilling.

FWIW, I was trying to find that exact same P/N the other day too... I'll let you know if I find anything.

The copper nuts:

[Glene]

Originally Posted by relative4

Put the flange in a vise, heat it up, and beat out the stud with a bigass hammer.

Can't put it on the vise if I can't get it off the car.

[rt7085]

Originally Posted by e90yyc

Man I must be lucky... In preparation for dropping the exhaust to replace the driveshaft guibos and center support bearing, I figured I'd try to remove those nuts the other day when I was already under my car for something unrelated. I thought that way I'd know what kind of a day I'm in for when I go to do the job...

I took one look at them and thought surely I was f*cked, but I was astonished when they zipped right off with the impact. This is after 200k miles in a climate where the roads are heavily salted about half the year. Looking at the front of the studs, I thought the corrosion I saw was the remains of what were once threads, but after removing the nuts I saw the threading was almost entirely intact. To be fair, the nuts on mine were in better shape than OP's, but still: I needed a 13mm for two of them, a 14mm for the third, and a 15mm for the fourth...

Apparently these are copper nuts, which might explain why they came off at all. I know this doesn't help you, OP, but I thought I'd share my story in case anyone else thinks they're screwed and just starts drilling.

FWIW, I was trying to find that exact same P/N the other day too... I'll let you know if I find anything.

The copper nuts:

The problem is that the original setup does not come with loose bolts; they are pressed or welded to the headers. The replacement part numbers are long bolts and copper nuts. I have these and planned to put those in to fix it. My bolts were clearly rusted, which implies they were iron or steel. Maybe some previous owner replaced them with the wrong kind at some point, but that is water under the bridge now.