# Help Removing Early Czech Zbrojovka Brno Bicycle Crank



## thisoldbike (May 3, 2015)

Hello sportsfans.  I have a 1920s Zbrojovka Brno bike that I am going to restore.  I've removed one side of the crank but cannot figure out how to remove the other side.  The side with the sprocket came off with a gentle tap of the hammer.  No luck on the other side.  Hope someone on the forum can assist.  Thanks.


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## vincev (May 3, 2015)

Are you sure the other side is not s left hand thread?


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## thisoldbike (May 3, 2015)

By 'left hand thread' you mean the entire assembly should unscrew counterclockwise?


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## vincev (May 3, 2015)

counter clockwise would tighten instead of loosen.


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## vincev (May 3, 2015)

Righty Tighty, Lefty loosey doesn't work with left-handed screws


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## thisoldbike (May 3, 2015)

Ah okay.  So if I've got this right, hold the one side with a crescent wrench and tap the crank arm clockwise?


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## thisoldbike (May 3, 2015)

Okay ... tried that and she don't budge.  Looking down the barrel of the crank there appears to be a square bold matching the other side but can't be 100% sure.


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## Andrew Gorman (May 3, 2015)

It looks like it is a square taper.  Will a modern crank puller fit the threads on the remaining side? Try to find one of the old tools with TA and standard threads.    If not, try a small 3 jaw puller on the on the crank.  If it is stubborn some lube and heat can't hurt.  Let Saint Sheldon be your guide:
http://sheldonbrown.com/tooltips/cotterless.html


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## thisoldbike (May 3, 2015)

Thanks Andrew.  I've give that a try and post an update shortly ....


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## Andrew Gorman (May 3, 2015)

Threads should be standard on the non-drive side.  IF you can get a good grip on that dust cap you may be able to force the crank out enough to either pop it off ot get the puller jaws in there.  Very cool bike, buy the way!


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## thisoldbike (May 3, 2015)

The dust cover moves with the crank so I assume its one piece.  There's a small lip that I may be able to get the jaws on but but the metal is very thin ... concerned that any real force may bend it out of round. I'll take a slow and careful approach ... a visit to my local bike shop may be in order.   Agree ... this thing is pretty cool.  Nice lines.  That think handing over the handlebars is the early 3-speed shifter ... the mechanism is really wild ... hope to get her back up and running soon but have a lot of work to do.


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## Andrew Gorman (May 3, 2015)

The dust cover might just be snugged up against the crank.  I would not try the puller on the dust cap- only the crank.  Depending on where you are I would try a bike co-op over a bike shop.  Co-ops have more witch doctors on staff.  How is your Czech?  With Google translate you might be able to scare up some information, and there is a STELLAR bike museum in the Republic- they might be able to help you out:
http://www.sterba-bike.cz/section/aboutus?lang=EN
Now I have to go back and look at your shift mechanism....


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## Jeff54 (May 3, 2015)

thisoldbike said:


> Hello sportsfans.  I have a 1920s Zbrojovka Brno bike that I am going to restore.  I've removed one side of the crank but cannot figure out how to remove the other side.  The side with the sprocket came off with a gentle tap of the hammer.  No luck on the other side.  Hope someone on the forum can assist.  Thanks.




You're talking about the crank arm right?

if that's so, your photo is showing the square fitting to be out of alignment, that's probably got it wedged in, so, try tapping it until the square is corrected.

I wouldn't be trying a wheel puller until you've corrected the alignment because you'll damage the fittings more, Hold the other side with a big wrench and tap, smack  that arm until it's where it should be. :


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## thisoldbike (May 3, 2015)

Another good suggestion.  I looked at the alignment and that does not seem to be an issue ... tried a few more taps and got nothing ...


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## Jeff54 (May 3, 2015)

thisoldbike said:


> Another good suggestion.  I looked at the alignment and that does not seem to be an issue ... tried a few more taps and got nothing ...





. Obviously you're not going to get a wheel puller on that, I'd be  knocking it back and forth until the wedge or corrosion breaks loose.


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## thisoldbike (May 3, 2015)

You may be right but given my experience restoring old things in general I am going to see if a wheel puller will screw on to the inner threads used to screw on the small crank dust covers ... keeping my fingers crossed that that they are a standard size.  I can't find any parts online for this maker so can't afford to make any fatal errors ....


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## Jeff54 (May 3, 2015)

thisoldbike said:


> You may be right but given my experience restoring old things in general I am going to see if a wheel puller will screw on to the inner threads used to screw on the small crank dust covers ... keeping my fingers crossed that that they are a standard size.  I can't find any parts online for this maker so can't afford to make any fatal errors ....




I didn't notice those threads before your mentioning them but cant think of a puller that'll get in there. and probably not a good idea to try pulling from that domed cover thingy, yet wonder why it's got the etched or raised notches as if they're intended for grabbing with pipe wrench when unscrewing.  However you said it turns with the arm, so, maybe they are there to remove it from the arm after it's loose.. But it's curious they're there, as if meant to be used when disassembling the arm. Perhaps, somehow, it wedges the arm tight. You might attempt to move it while fixing the arm from turning too. Maybe it'll open up enough space to get a puller's arms onto the crank arm. 

In the mean time;
You could latch a couple of pieces of wood on to the crank arm, on each, top and bottom side so you'll be able to get some hard smacking action. A large rubber mallet might work so it wont damage the arm but, sometimes they don't have the same hard effect as a metal hammer, to get a shocking jolt, yet with wood fastened on flat, enough force may hit through and keep the arm from dents.

On another note; is there a circlip or C ring holding the shaft in place in this photo? Sure looks like a large C clip end @ 6:15 o'clock in photo. if so, I'd yank it to see if can slide out the shaft, then get a complete view of what's on the other side and enable you to stick it in a vise. maybe the dome thingy's (end cap)  notches  are for tightening/ajusting the shaft against the C clip. From this angle I wouldn't want to be sticking a pipe wrench on those notches, unless bery bery carful, it's too thin. And makes me think; it's designed so that the end cap can be adjusted by hand:


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## Andrew Gorman (May 3, 2015)

I like that idea- take all of the bearings, etc.  out on the drive side and see what room you can manufacture on the "stuck" side, or takr the crankaxle out altogether.


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## thisoldbike (May 3, 2015)

Jeff54 ... I noticed those raised slots / grooves as well and, like you, thought they are intended for grabbing and unscrewing.  I've tried to turn it by hand but the thing won't move even a mm. Maybe once the arm is off I'll be able to see if its welded or otherwise attached.

I like the idea of tying pieces of wood on to the crank arm to protect it from the hammer.  With my luck I'll smack it just right so that it will bend or worse!

The photo does appear to show a C ring holding the shaft in place but its just the photo.  I've attached a bird's eye view ... each elevation is a complete circle and moves with the crank arm.

I cant imagine this being too complicated given that the thing was made in the 20s but who knows ....


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## filmonger (May 4, 2015)

Does this help?.... you can always ask this guy - he would know http://www.sterba-bike.cz/fotka/16689/category/information-mix-foto?lang=EN









Google translate.... not the best but you get the idea

In the 1935 season we introduced a specially branded with wheels

that does not require repairs or adjustment and guarantees an ideal smooth running round the center-we bring portrayed won in a short time so fond of them equipped with wheels became the most popular and most demanded our models


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## johnnybentwrench (May 4, 2015)

Did you heat it up???


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## thisoldbike (May 4, 2015)

filmonger said:


> Does this help?.... you can always ask this guy - he would know http://www.sterba-bike.cz/fotka/16689/category/information-mix-foto?lang=EN
> 
> View attachment 212441
> 
> ...




This is great!  It looks like both sides just pull off .... maybe a little heat and hammer will do the trick.  Thanks for finding this.


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## thisoldbike (May 4, 2015)

*Success !!!*

That old illustration was a BIG help ... good to know what you're dealing with before taking the almighty hammer to the arm.  Applied a few mins of heat, attached a piece of wood to the arm, two good hits and off she came.  Thank you all for the assist.  Now to the bearing ...


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## thisoldbike (May 4, 2015)

Okay ... so after cleaning up the area under the cap, this is what I have ... any suggestions on what next steps to take to remove the shaft and to get access the the bearings?


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## thisoldbike (May 4, 2015)

*Update ...*

Okay ... with a bit of work it budged and finally came apart ... I'll move this to the forum 'project' section to keep you'all up to speed on the restoration.  I am sure I'll need more help going forward


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## filmonger (May 5, 2015)

I think you did incredibly well....wish everyone would ask their questions with a followup photo! look forward to seeing the final product.


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