BB was seized, there is rust inside and what looks to be bits of the aluminim in the cups still in the frame threads (as well as rust in the tubes).
Is this too far gone or can I clean it up with some wire brushes and apply some antirust oil and rebuild the bike?
by dopethrone
5 Comments
The threads in your first picture look pretty beat up to me (on the rear side in front of the chainstay). You may be able to have a shop chase the threads for you.
Even if the threads are gone, you can still use the bike with a rescue bottom bracket. For example the [YST BB993](https://www.yst-corp.com.tw/products-view-bb-993.php). These BBs screw into themselves, not the bottom bracket shell.
It’s impossible to diagnose the extent of rust from a couple pictures on the internet. What we can see is the thickest part of the frame and the rust there looks like surface rust and not a structural concern. Big caveat, however, that we can’t see much of anything!
The threads can be cleaned by making your own thread chaser from an old set of steel BB cups. Alternately a shop can chase them for you for a cost: https://www.youtube.com/watch?v=1IrAGP22V34
As for cleaning up the frame, here’s a method for submerging an entire frame in [evapo-rust](https://www.evapo-rust.com/), which is [paint safe](https://www.youtube.com/watch?v=fE2fau_gXRw): https://www.bikeforums.net/classic-vintage/1224954-rust-around-bottom-bracket.html
Examine your frame and you may find that only the chainstays and BB need the evaporust treatment, in which case you can make a smaller container and fix the frame standing vertically. I’ve used an old clear plastic shower curtain + old shipping boxes instead of building a frame out of wood.
Once you’re done removing rust, clean and dry the inside and give a liberal coat of boeshield t9 to the entire inside of the frame. work that around and pray it through all the little holes.
looks like a dirt to me, not rust
You can chase it and face it for sure.
It looks like the threads have been flattened some. I would chase the threads and see if they clean up better than this. If it’s just a bar bike you could install a BB and see how it goes.