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Old January 10th 17, 09:15 AM posted to rec.bicycles.tech
John B.[_6_]
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Posts: 2,202
Default Need advice on bottom bracket repair

On Mon, 09 Jan 2017 19:48:48 -0600, AMuzi wrote:

On 1/9/2017 7:44 PM, John B. wrote:
On Mon, 9 Jan 2017 22:17:31 +0000 (UTC), Theodore Heise
wrote:

On Sun, 8 Jan 2017 14:59:56 -0800 (PST),
DATAKOLL MARINE RESEARCH wrote:
On Sunday, January 8, 2017 at 12:59:14 PM UTC-5, Theodore Heise wrote:
On Sun, 8 Jan 2017 08:56:40 -0800 (PST),
wrote:

Ted, I don't quite follow. You are talking about using a
pin spanner and then say that you need to get the
adjustable cup off first. Isn't that what we were talking
about? The lock nut on the adjustable side and the fixed
cup do not use pin spanners as far as I know.

Sorry. I have the lock ring off on the left, non-drive side,
and am left with an adjustable cup that will only turn
partway. The fixed cup is still in place too (on the other
side), so the spindle is in place and blocks putting in the
bolt and nut that Sheldon describes.

For what it's worth, the fixed cup also seems to be pretty
stuck. It's an aluminum frame, so presumably the shell is
aluminum too and there may be some corrosion in the interface
between the two different metals of the shell and the cups?

if you search on aluminum/steel frame/shells/cups install or
remove there should be an avalanche of umbrage.

if your system shows white material in joints then poss an
ionic binding occurred between steel and aluminum. Andy Muzi is
an expert on this.

Blaster does not dissolve the white material. Uneeda torch and
another pin tool.

expanding aluminum with torch or heat gun will remove the cup.

Okay, I will try heating too.


You might want to know that as a general statement aluminum bike
frames are heat treated after welding and heating aluminum to
approximately 300 - 400 degrees C will anneal it.

As an aside, probably because of the ability of aluminum to rapidly
transfer heat, my experience in heating cylindrical objects to enlarge
them has been spotty at best. If you heat the cylinder in an oven so
that the entire devise is an equal temperature then it will enlarge to
a rather surprising amount. If you try the same thing with a torch it
doesn't work so well as, I suspect, while you are heating one side the
other side is merrily transferring heat to the air or supporting
structure so what you end up with isn't a circle but an oval.


No argument with any of that, good advise.

Moderate (120~150F) heat from a heat gun seems to help
penetrants. Lighting the work on fire may have entertainment
value, but probably won't help with the actual mission.


Yes it might work but I would suggest three or four heat guns located
radially on all sides to get as even a heat as possible. Start the
heating and than go off and have a cuppa or watch youtube and come
back "after a while" and try it.
--
cheers,

John B.

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