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Old 10-26-08, 12:00 AM   #1
mike
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Grease cotters on cottered cranks?

This is really an old-school discussion. Maybe it belongs on the Vintage forum.

Anyway, tonight I cleaned and re-packed the grease in an old Raleight three-speed.

Through the patience of allowing penetrating oil to soak in for three days and through a time-tested method of whacking the cotter pin out, I managed to get the cotter pins out perfectly without damage.

Yes, yes, I am proud. You know how hard it is to get the correct sized cotter pins these days. I mean, I just don't have any laying around.

So anyway, I am putting the puzzle back together and I ask myself, "why not put just a little swipe of grease on the cotter pins so that they come out easier next time?

Any opinions on this? It seems to make sense, but if it does make sense, why didn't they traditionally do this during factory assembly?
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Old 10-26-08, 01:21 AM   #2
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Have you checked Sheldon Brown? He seems/seemed to be the authority on this kind of stuff.

R.I.P Sheldon "insert ridiculous nickname here" Brown.
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Old 10-26-08, 03:42 AM   #3
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I have always greased cotter pins before installation, and also greased the threads on the pin for the bolt that holds it on. As long as that bolt is tight enough and the pin isn't deformed, I don't see why there would be an issue.
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Old 10-26-08, 05:42 AM   #4
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I don't grease them when putting new pins in.
I also don't know of a good source for new cotters. We have a shrinking supply which we covet.
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Old 10-26-08, 08:36 AM   #5
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Take a bow, you are a better man than I. Last time I tried removing cotters I tried everything, hammer, press, penetrating oil and heat, nothing. Now I just leave them and my bottom bracket maintenance consists of three or four squirts of oil from an oil can down the seat tube every once in a while (about the same time I oil the SA hub) until the excess oil leaks out the BB.

But yes definitely grease the pin! When I worked as a wrench, the master mechanic insisted on grease. A cotter is an interference fit and grease makes the interference fit stronger, helps prevent galling from metal on metal contact and of course makes it easier to get out because you don't have to apply as much pressure to a lubricated interference fit to get it to hold.
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Old 10-26-08, 08:47 AM   #6
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try bikesmithdesign.com for your cotter pins need and they also sell a press that work great too. using grease is a good idea too.
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Old 10-26-08, 12:19 PM   #7
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I also used to apply grease on cotters way back in the '70-ies.

One tap used to be enough to get the (greased) cotter back out. If you unscrew the nut just far enough and let it sit on the threads it will not deform nor be damaged by one (gentle) tap.

BTW do not hit the cotters without supporting the BB axl. The bearings and races do not like a violent approach.
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Old 10-26-08, 12:42 PM   #8
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Brass or other soft metal headed hammer works wonders for helping to avoid damage to threads and stuff like this. And a big hearty double ditto to supporting the crank arm with a big heavy block of metal to take the shock instead of the BB bearings. I keep a big 3'ish lb block of scrap aluminium around for such things.
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Old 10-26-08, 05:48 PM   #9
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Quote:
Originally Posted by Berre View Post
I also used to apply grease on cotters way back in the '70-ies.

One tap used to be enough to get the (greased) cotter back out. If you unscrew the nut just far enough and let it sit on the threads it will not deform nor be damaged by one (gentle) tap.

BTW do not hit the cotters without supporting the BB axl. The bearings and races do not like a violent approach.
+1. This is how I have been removing cotters the past few years - Berre's suggestion PLUS, let some penetrating lubricant like WD-40 soak around the cotter overnight or longer.

This method has been working pretty well. I have had a couple of cotters that were just welded in - wouldn't budge. The cotters got all banged up and bent, but I eventually got it off. I think in one case, I had to cut the crank arm off. Cotters do indeed suck, after all.

So, I DID grease the cotters in respect for the next guy who takes the cranks off 30+ years from now.
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