Was just stripping the frame for some cleaning and painting. Four of the threaded inserts on the frame started spinning freely with very little torque. Thankfully they weren't holding anything on, so it's just the bolts stuck in them.

Used some penetrating fluid and pliers, but no luck. Any ideas for removing the bolts besides drilling them out?

Any way to repair or replace these inserts? Quick search didn't turn up much, but I have a feeling I'm not using the right terminology.

https://www.parktool.com/blog/repair...ottle-fittings

I knew I was using the wrong word haha. Found replacements easy by searching for bike rivnuts. Pressure of the flange was a no-go. It's weird, since all the others came out very easily with little breaking pressure needed. I like the adhesive idea - might try JB Weld too.

Thanks!

Well... That was fun. Probably going to drill out the holes a little and replace with M6 aluminum rivet nuts. Pairing that with 12mm long zinc-plated steel hex screws, hot dipped steel/neoprene sealing washer, and aluminum based antiseize - should prevent any future corrosion issues!

Try Tef-Gel, I use it on all dissimilar metal joints. I would also suggest stainless fasteners over zinc-plated. https://www.tefgel.com/contain.php?param=tefgel_infor

Never heard of Tef-gel. Seems to promise some great things though, might have to add it to the garage. Got enough of these types of things that I should just do a comparison test. Still reading about it, but it seems like the main benefit of it is for very dissimilar metals, galvanic-ly speaking. Coming from an automotive background, I'd normally use nickel antiseize in that situation. Any reasons you prefer the Tef-gel?

As far as stainless fasteners... Well the above is actually one of the reasons I tend to avoid them. But if that's not a concern...

Edit: Here's my reasoning for the choices of metals listed earlier:

-Aluminum rivet nuts - last thing I want to see corrosion is the frame. Since this will sit direct against the frame metal and damage any coating I might try to apply, it seemed like a good idea to avoid a dissimilar metal.
-Hot dipped washer - very resistant to corrosion from the elements. The large amounts of zinc will act as a sacrificial anode.
-Screws - three main options are listed below. The zinc plated steel seemed a good compromise between the two others, and is also the strongest of the three if that matters.
-----Stainless steel (extremely corrosion resistant, but will cause galvanic corrosion of aluminum if preventative measures aren't taken)
-----Zinc-plated steel (very corrosion resistant and will not induce significant levels of galvanic corrosion of aluminum)
-----Aluminum (corrosion resistant, but not to the same degree as above. Practically no risk of galvanic corrosion with other aluminum)

I originally began using Tef-Gel when I lived in the Northeast where roads were salted for 4+ months/year; it resembled the marine service Tef-Gel was designed for. Its high PTFE content adds lubricity and helps avoid galling of stainless and presumably Ti; works great on pedal and BB threads.
Anti-seizes with nickel and copper excel at high temperature service (think exhaust systems) which is not an advantage for bikes. I also think that introducing one or more additional metals into a galvanic mix may be less than helpful.
I think that threaded fasteners made of aluminum (cough, spoke nipples, cough) are a mistake in most instances, especially vs other aluminum parts.

No point in going up to M6, unless you duffed up a hole removing it. You would be forever drilling out holes in bottle cages/accessories, since they are sized for smaller M5 screws.

I've always wondered how nickle antiseize apparently reduces corrosion. Everything I've read suggests its use there, but the very little of the chemistry I know would make me think otherwise.

I'm actually counting on that! I always prefer close fit rather than normal or loose for clearance holes. Most are oversized and the M6 will fit fine. For those that are actually sized more precisely, I don't mind expanding the <1 mm it would take.

There are probably the occasional items that have an integrated screw. Haven't used one yet though, so will figure that out if it ever becomes an issue.