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Lockring stuck on bracket Cup
#1
Hey,

I am trying to restore an old 1955 Triumph that I bought at a car boot sale. I was removing the bottom bracket today and have been having a problem removing the lock ring. I was using a hammer and punch to turn the lock ring (it was very stiff). Once it was loose I managed to remove it almost completely before it got stuck again. When I resumed using the hammer and punch I ended up just loosening the bracket cup which has now come free with the lock ring still attached.. I can get the cup back on but the lock ring doesn't go flush and I am concerned it will not be properly sealed.

Apologies if this isnt clear but I have attached a photo to make it clearer hopefully!

[Image: IMG-20141023-WA0001.jpeg]

Thanks,
Sam
  Reply
#2
You definitely need to get the lock ring moving so you can adjust the BB when you put it back together. You could try soaking the whole thing in a rust breaker like PB Blaster. If you can get the lockring moving back deeper onto the cup, you may be able to screw it all the way off to the inside instead. It may be that the outer threads are damaged rather than rusted and that is why it is binding.

Last resort could be to carefully cut the lockring with a hacksaw. You should be able to do this with minimal damage to the threads on the cup. Of course, you would need a new lock ring. But you should be able to find something that at least looks similar. (Unless this has some weird English threading?)

I'd be careful about clamping this in any way as your try to work it off, you don't want to crush the cup.

Have a shop chase the threads on the frame before you reassemble.

(This all assumes the cup itself isn't pitted on the inside. If it is, you either need to try to polish the bearing surface or make a decision about replacing it anyway.)
  Reply
#3
Hey,

Thanks for the quick reply. I will leave it soaking over night and see if that helps. I am concerned that it has slipped and so soaking wont help. It was slightly loose when I was trying to remove the pedal crank and I think it may have got bumped slightly :S

Time will tell.

Thanks again.
  Reply
#4
If soaking in solvent does not work, try Oxalic Acid; in the USA most automobile parts stores have, it is a rust remover. http://en.wikipedia.org/wiki/Oxalic_acid
Nigel
  Reply
#5
You might want to clean and inspect the cup to make sure it's good enough to reuse, lest you put in a lot of work for nothing. Of course if it is bad it will be a challenge finding a compatible cup, as the old English 3 speeds used different threading (26 tpi). You are essentially relegated to trying to scavenge some. Even back in the 70's the cups were hard to find.
  Reply


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