[Tim17]

I have been doing downpipes and replacing O2 sensors on my 2008 E90 335i.

Just below the downpipes there is a v cross brace going from the subframe in the centre angled back behind each wheel. It is secured with 6 nuts in total. I am struggling to remove a few of them as they are spinning to no avail. I have tried everything just need some advice on the best option. Im guessing they were overtightened or siezed in place from the previous owner and I snapped the weld nuts loose inside when I attempted to remove them.

I want to cut the bolts and try removing the nuts with a magnet out the end of the subframe. Then cut a square out of the subframe to reweld a new nut and then patch up as strong as possible. Double layer if need be.

What is my subframe made out of to re weld? And can I cut a small hole to re-set a nut? Does this compromise the strength of the subframe?

Any help is appreciated, thanks.

[slupie]

here is the diagram from realoem, figure out which ones are broken loos and if they are #7 or #8, if yes then reach with a wrench above the cross member and get the bolt out. That is what broke on mine when I did the oil pan gasket.

http://www.realoem.com/bmw/enUS/show...diagId=31_0814

Or post pictures of which ones are broken on yours.

[Tim17]

Originally Posted by slupie

here is the diagram from realoem, figure out which ones are broken loos and if they are #7 or #8, if yes then reach with a wrench above the cross member and get the bolt out. That is what broke on mine when I did the oil pan gasket.

http://www.realoem.com/bmw/enUS/show...diagId=31_0814

Or post pictures of which ones are broken on yours.

Thanks Slupie, I believe they are 7 and 8. Im assuming they just slot in the top and I can get a spanner on them easy enough.

[mweisdorfer]

I had the same exact problem.

Use BMW FANS to get the part number for new fasteners.

You will have to cut the bolts off with a sawzall.

Get a Diablo carbide tipped blade. It will go through the bolts like a hot knife through butter.

I Dremmel May also do the trick, but you will go through a lot of blades.

Also, when it's all said & done and your putting the V bar back into place with the new nut fasteners, slather the bolts up with some anti-seize.

I'd use some nickel based anti-seize on the bolts that secure the downpipes to the exhaust flange.

https://www.ecstuning.com/b-genuine-...h/31106779393/

[slupie]

Originally Posted by Tim17

Thanks Slupie, I believe they are 7 and 8. Im assuming they just slot in the top and I can get a spanner on them easy enough.

You might be able to get a open end wrench on the nut and get the bolt out, if not cut the bolt and replace both like mweisdorfer said.

In my case I had only one do that after the car living all of it's life in the rust belt (northern Illinois).

[blueloco]

Originally Posted by mweisdorfer

I had the same exact problem.
You will have to cut the bolts off with a sawzall.

Get a Diablo carbide tipped blade. It will go through the bolts like a hot knife through butter.

+1 on the Diablo blades. I literally cut my brake rotors in two with these on my truck. This after my 10 ton puller pulled its hooks right through the rotor. Next time I am working on front rotors that are completely seized on the hubs I am going straight to the Diablo. Sorry a little off topic but man those are great!