drexal77
Dirt Disciple
Hi guys,
Keep running into issues with my restoration of a 1990 Alpine Stars Al-mega DX. I finally managed to remove the plastic SKF bottom bracket, that was super rough. But the corrosion on the BB has caused damage to the aluminium shell and caused the threads to become very pitted. And now the replacement bottom bracket won't screw in all the way, it sticks out by about 4mm the same goes for the collar side.
Just some detail on shell size and bottom bracket etc (although this probably isn't needed).
Shell size is 73mm, and i'm replacing the SKF with a Tange Seiki 73mm - 122mm ( i tried a Shimano BB UN71 in there as well, but same issue gets very close to the bottom and then stops. I could possibly keep tightening and see what happens. But scared i might make it worse and don't want to mess up the threads on the new BB.
Please see images of pitted threads, my plan is to buy a BB tapping/facing set and to try and tap the inner threads through. If you think this is the best thing to do?
Looking at the pits can any of suggest some sort of metal paste almost like a JB Weld style substance i could add to the pits to build them up, so when i tap it should cut though this dried metal paste and create a thread? (sorry i'm probably not explaining myself very well, but i hope you get what i'm trying to ask)
Any help or advice would be hugely appreciated.
Keep running into issues with my restoration of a 1990 Alpine Stars Al-mega DX. I finally managed to remove the plastic SKF bottom bracket, that was super rough. But the corrosion on the BB has caused damage to the aluminium shell and caused the threads to become very pitted. And now the replacement bottom bracket won't screw in all the way, it sticks out by about 4mm the same goes for the collar side.
Just some detail on shell size and bottom bracket etc (although this probably isn't needed).
Shell size is 73mm, and i'm replacing the SKF with a Tange Seiki 73mm - 122mm ( i tried a Shimano BB UN71 in there as well, but same issue gets very close to the bottom and then stops. I could possibly keep tightening and see what happens. But scared i might make it worse and don't want to mess up the threads on the new BB.
Please see images of pitted threads, my plan is to buy a BB tapping/facing set and to try and tap the inner threads through. If you think this is the best thing to do?
Looking at the pits can any of suggest some sort of metal paste almost like a JB Weld style substance i could add to the pits to build them up, so when i tap it should cut though this dried metal paste and create a thread? (sorry i'm probably not explaining myself very well, but i hope you get what i'm trying to ask)
Any help or advice would be hugely appreciated.
