[s54_guy]

So I'm in the process of swapping out my stock downpipes with the VRSF ones and of course I ran into issues with the infamous downpipes to midpipe bolts/studs. I have a 2010 n54 135i and the bolts are completely corroded.

I initially let PB blaster soak them in for at least an hour before attempting to loosen them. I searched online and saw that people suggested to other forum members cutting them with a dremel or heating them. I attempted to use the dremel but failed miserably. I don't have a torch. And so I moved on to try and cut a 'slit' and use a punch an hammer to loosen them. Also failed. Last but not least I attempted to drill out the bolt and use a tap. Also did not work. Even if these methods did work, I'm not sure how I would be able to get to the top bolts.

Anyone have any suggestions? I'm not really sure what else I can do but the studs look horrible and I feel like I should just put everything back together and send the car to shop to have the studs/bolts removed.


Bottom bolts that Drilled out or cut




Top bolts still untouched

[Miller335]

There's a good amount of weight/tension on those bolts, get a jack under the mid-pipe and take some of that tension off of the bolts first.

See if you can get some heat on them and then try again.
Not sure what the best plan is to drill out the studs though but I know others have done it.

[N54Bob1988]

I beat on a 12 point socket that was one size smaller and use my impact to get it off. Other than that ive had to weld sacrificial sockets on them too

[s54_guy]

alright so I started brainstorming ideas and I decided that I would take the entire exhaust off, since the dp's were already loosened from the V clamps. Upon doing so, I had much more leverage and better angles to tackle the job. I used a dremel and metal wheel cutter and just slowly cut the nut and excess bolt until it was flush with the flange. I then hammered the midpipe and dp until they both seperated. VOILA! DAY SAVED.

The stock dp's studs will have to be drilled out if I ever plan on using the stock dp's. Mid pipes took 0 damage and are good to go. I have all new set of bolts and nuts but I'll tackle that tomorrow. Exhausted from all this (No pun intended) Physically and mentally.

Thanks for the advice guys. Definitely appreciate the quick feedback.

[tanishh]

When you dropped the whole exhaust system as one was it difficult or was there anything that had to be moved for optimal clearance? I know its been 5 years since lol but just looking to tackle the problem the same way as well... super frustrating

[relative4]

Just a little shield to remove. Once that's off, disconnect the vacuum line, put a jackstand under the crosspipe, loosen the muffler bolts, then unbolt everything starting at the front.