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PostPosted: Sat Jan 26, 2013 2:06 pm 
Old School Hero
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Joined: Sat May 05, 2012 6:33 pm
Posts: 216
Location: East Yorkshire
I am rebuilding a '79 Carlton Professional and it has a period (original I think) Shimano BB.

I removed with the correct tools, cleaned and re-greased, and now can't get the bugger back on! :(

Firstly I am aware of the reverse thread on the driveside! I have been very careful, not trying to force anything for fear of cross threading, but cannot get the drive side to catch at all. On the other side I can get the BB in about two revolutions by hand and then it stiffens up so that I cannot turn by hand any further. Again I have not applied any force at this stage.

I have had the frame powercoated, but the threads were masked and I have cleaned them up with a rough sponge and WD40. There were no issues with any of the other threads.

Any ideas? Am I be too cautious?

Any help welcom as once the BB is in and the cranks fitted it is almots complete! :D

Vimes


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PostPosted: Sat Jan 26, 2013 2:34 pm 
Old School Grand Master
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Joined: Fri Oct 14, 2011 8:41 pm
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Location: Cumbria
Don't be tempted to force it using the removal tool, very easy to cross thread. We used to run a tap through the BB every time a frame came back from being re-finished.

Has the powdercoat a clear coat which has gone on the threads?

Shaun


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PostPosted: Sat Jan 26, 2013 2:39 pm 
Old School Hero
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Location: East Yorkshire
No clear coat. I have run my fingernail through the threads and they feel OK. There are a couple of minor catches on the BB itself when I do the same, but the nail continues around the thread.


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PostPosted: Sat Jan 26, 2013 3:10 pm 
Gold Trader
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Location: Manchester, UK
Are the threads on the cup(s) ok? Maybe you could clean up the threads on them using an old steel lockring with a slot cut into it (making yourself a DIY die)?

From what your saying there's nothing you seem to be doing wrong though! If in doubt, get the frame threads chased?

FWIW, when I am being careful not to cross thread (esp with alu frames) I turn the cup in the opposite direction first, you get a distinct point where you can tell the threads have locked together correctly, then I start to turn in the correct direction. Sure you knew this, just sayin' :wink:


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PostPosted: Sat Jan 26, 2013 6:53 pm 
Old School Hero
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Joined: Sat May 05, 2012 6:33 pm
Posts: 216
Location: East Yorkshire
Thanks for the advice guys.

I remembered that I had a spare, new Shimano BB. When I tried this it did not take too much effort to get it on. So it looks like it is the old cups.

Shame, as almost everything else on the bike is original or period (except the pedals) but at least you cannot see it has a modern BB!

Only the brakes to fit and original wheels to clean up and fit and see is finished!

Vimes


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PostPosted: Sat Jan 26, 2013 8:12 pm 
Gold Trader
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you said there are a couple of points on the BB where you catch your nail when checking it... remove those and try again!


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