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-   -   Something is loose in my crank arms, having trouble getting the dust caps off. (https://www.bikeforums.net/bicycle-mechanics/930290-something-loose-my-crank-arms-having-trouble-getting-dust-caps-off.html)

15cm 01-17-14 06:58 PM

Something is loose in my crank arms, having trouble getting the dust caps off.
 
1 Attachment(s)
I'm doing a winter project to keep myself busy. I've run into something that hopefully someone has a solution to. A picture is worth a thousand words:

http://bikeforums.net/attachment.php...hmentid=360048


I'm unable to get a screw driver or knife under the dust caps to pop them off, when I spray it with wd-40, it seeps inside, so I'm know it's not a screw top. Before I drill a hole in it to pop them off, does anyone have some sound advice?

I'm hoping to not have to go into the local bike shop with a frame under my arm and my tail between my legs.

15cm 01-17-14 07:02 PM

Those are Sugino cranks from what I believe to be a 78 Apollo.

Matariki 01-17-14 07:17 PM

Those are steel cottered cranks. There is no dust cap, the thing you are prying at is the end of the spindle.

Read the stuff here before you get out your power tools: http://sheldonbrown.com/cotters.html

flyfisherbob 01-17-14 07:19 PM

That is a cottered crank. I don't think they have dust caps (at least that is how I remember them). Check the inter-webs, I'm sure youtube will have instructions on how to remove them. Good luck.

hueyhoolihan 01-17-14 07:45 PM

if cottered, and it does look to be, especially since it is a steel crank, remove the cotter pin (easier said than done one an old bike) and the arm should slide off with a little encouragement.

FBinNY 01-17-14 07:56 PM

Here's how to remove the pin (and crank). If you have a bench vise, clamp a short of pipe so it's resting on the section supporting the movable jaw. This is now your anvil for the job. Have a friend hold the frame with the crank over the end of the pipe, with the pin inside, screw end up. Use a heavy steel hammer and deliver one blow to the pin with enough force to drive it to China in one shot.

If you doubt your hammer skill, clamp a punch in a visegrip plier and hold it against the pin and drive it down. The reason I suggest holding the punch with pliers is that most people are nervous about crushing their hands and won't use full strength on the hammer.

The goal is to push it out in a single blow, otherwise you end up mushrooming the pin instead.

15cm 01-20-14 11:40 AM

Awesome. Thanks everyone for the replies. I'm glad I posted here before drilling holes into things. I was able to get out one side by, as FBinNY posted, "Drive it to China."

I'm still fussing with the other side, as I of course "mushroomed" it. Tonight, I'm going to use the SB method of using the removed crank as an anvil.

FBinNY 01-20-14 11:48 AM


Originally Posted by 15cm (Post 16426000)
Awesome. Thanks everyone for the replies. I'm glad I posted here before drilling holes into things. I was able to get out one side by, as FBinNY posted, "Drive it to China."

I'm still fussing with the other side, as I of course "mushroomed" it. Tonight, I'm going to use the SB method of using the removed crank as an anvil.

Use a hacksaw and cut the mushroom cap off flush (or close) the the face of the crank. Now set it up on the pipe, or other crank as an anvil, set a punch against the stub, and drive it out, with enough force to drive it to China so fast that it leaves the ground and heads for the moon.

The key is that if there's not enough force to blow it out, it'll mushroom instead.

Homebrew01 01-20-14 11:57 AM

I sometimes unscrewed the cotter pin nut so it was flush with the end of the pin. Then the hammer will hit the pit & nut at the same time, spreading the load to the pin tip, and threads. Less likely to mushroom the end of the pin.

When installing a pin, don't drive it to China. Tap it in a bit more gently.

15cm 01-20-14 02:19 PM

Thanks Homebrew01 - I have no intention of installing these again. Once they're out, I'll be shopping for new crank, chain ring and, if necessary, bottom bracket.

Crescent Cycle 01-20-14 02:21 PM

You will need a new bottom bracket, the spindles for cottered cranks are cotter specific.

cny-bikeman 01-20-14 02:36 PM

You don't need to hacksaw the pin at all. Just put a flat punch to the side of the threads and knock it back and forth a couple times. It will break off and then allow you to put the punch inside the hole so that it won't slip out of place.

seedsbelize 01-20-14 06:05 PM


Originally Posted by FBinNY (Post 16420331)
Here's how to remove the pin (and crank). If you have a bench vise, clamp a short of pipe so it's resting on the section supporting the movable jaw. This is now your anvil for the job. Have a friend hold the frame with the crank over the end of the pipe, with the pin inside, screw end up. Use a heavy steel hammer and deliver one blow to the pin with enough force to drive it to China in one shot.

If you doubt your hammer skill, clamp a punch in a visegrip plier and hold it against the pin and drive it down. The reason I suggest holding the punch with pliers is that most people are nervous about crushing their hands and won't use full strength on the hammer.

The goal is to push it out in a single blow, otherwise you end up mushrooming the pin instead.

This just blows my mind. I had my first ever cottered crank refurbish in the stand when I read this. Worked great! FB comes through again.

Homebrew01 01-20-14 08:06 PM


Originally Posted by Crescent Cycle (Post 16426439)
You will need a new bottom bracket, the spindles for cottered cranks are cotter specific.

And now would be a good time to find out what threading you have so you can order the right one. "English" is most common, but French, Italian and Swiss were common on certain brands.

Any numbers on the BB cups ?

FBinNY 01-20-14 08:15 PM

Once you have the cranks off, start by removing the right threaded left cup and lockring. Then you can measure and know what you have.

Hopefully this isn't a 40+ year old Raleigh product (Raleigh, Rudge, Dunelt, Robin Hood, etc.) since this opens the possibility of a 26tpi. thread. Otherwise, odds greatly favor a, ISO/BSC 1.27" x 24tpi thread, in which case the right cup will have a left hand thread.

15cm 01-20-14 10:13 PM


Originally Posted by Homebrew01 (Post 16427444)
And now would be a good time to find out what threading you have so you can order the right one. "English" is most common, but French, Italian and Swiss were common on certain brands.

Any numbers on the BB cups ?

D304 on the BB

Both cottered cranks are out. It took a few hits to knock the last one out.

I was able to get the left side off. It was right hand thread (a fortunate result of me mindlessly spinning the crank). I'm researching online to see what thread the right side(lock ring) is. Thanks for all of your help so far guys.

FBinNY 01-20-14 10:22 PM


Originally Posted by 15cm (Post 16427738)
D304 on the BB

Both cottered cranks are out. It took a few hits to knock the last one out.

I was able to get the left side off. It was right hand thread (a fortunate result of me mindlessly spinning the crank). I'm researching online to see what thread the right side(lock ring) is. Thanks for all of your help so far guys.

We can probably save you some effort on the BB thread front. What's the brand (on the head badge) and where was it made?

Knowing either or both, especially the country of origin can make it possible to know the BB thread about 98% of the time.

15cm 01-20-14 10:27 PM

Sweet. The head badge says its an Apollo. The only thing that points to country of origin is on the crank arm, "Japan G-3"

FBinNY 01-20-14 10:33 PM


Originally Posted by 15cm (Post 16427753)
Sweet. The head badge says its an Apollo. The only thing that points to country of origin is on the crank arm, "Japan G-3"

That's simple, it's now 99% certain you have an ISO/BSC 1.37"x24 BB. this is the most common, and gives you a nearly unlimitd choice of BBs.

15cm 01-20-14 10:48 PM

Beauty. Time to shop around! Thanks for all of your help.

3alarmer 01-21-14 10:57 AM

For Future Reference On Cotters, both Removal and Re-installation

.......NB that you need to press or somehow pound them back in.
It is a mistake to try pulling them tight with the nut...it will often strip.


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