Cottered Cranks
 

Is it even worth it to try to pull cranks and open the BB ? I'm looking at an opportunity to overhaul an old Raleigh Sports as a gift to an "Anglophile" friend of mine.

Trying to correct title. It should read cotter cranks. Thank you spellchecker!

Worth what? To accomplish what?

Is it a bear to remove the cotter bolts? Is it worthy of my expense to invest in something that I should be able to disassemble and reassemble? I'm worried I will break the bike trying to beat off those cotters

Can of worms. Everything smooth and spinning freely?

If you have a cotter press, it's usually not a problem to remove the arms and open the bottom bracket (there are threads here describing inexpensive, DIY cotter presses). Depending on how old the bike is, there may be an oil port on the bottom bracket shell that lets you lubricate the bearings without opening the bottom bracket. If you do remove the arms, use the press to re-install them as well to avoid damage.

I'm just going to pass. It turns, but the bike has been neglected by the elements. I already opened a can of worms on another bike with a seized seat post. I love rebuilding bikes, but I hate frozen metals or obscure needs for specialty tools on a single need

Cottered cranks is the correct term.

A short piece of lumber with a large counterbore is what you need- just rest the crank with the cotter above the bore, and tap it out with a machinist's hammer.

Yes, cottered. Cotter pins.

I would take the chain off the chainrings, then turn the cranks, feeling and listening for roughness, hoping for none, because it can become a major production unless you have access to a high quality tool like VAR.

If the bottom bracket bearings need to be serviced, and they likely do, then it's worth it in my opinion to pull the crank arm(s) off to clean/inspect/regrease the bearings. Yeah, it can be a bit of a pain, but it's a job worth doing to make sure it keeps working for many more years.

The job's significantly easier with a cotter press, but you can improvise. I've used the vise and socket method on a really stubborn old Peugeot.

Just do it. It builds character and isn't that complicated. Over at the C & V forum there are threads on how to do it without specialty tools.

Indeed, just do it. It's likely that the 40 (50?) year-old grease has hardened into wax, but if the bike has simply been neglected and not beat to shreds I bet all you will need to do is clean everything thoroughly (forget "mild" solvents- get a can of carburetor cleaner), fresh grease, and new cotter pins will have it running like new. Even if parts are rusty, I bet the old grease has preserved the insides of the bottom bracket.

Go online & buy a couple sets of new cotter bolts & nuts. Have on hand before starting work. In the meantime, start basting the crank set with penetrating oil or diesel fuel. Unscrew the cotter nut till it's 1/2 way off & tap it with a hammer. If it doesn't come loose no worries. Remove the nut, get a punch, & pound the living crap out of the cotter bolt till it pops out. (Why not - you're not going to re-use it. You got new ones). No big deal. Have fun. Be good.

Hammering on the cotter pins can damage the bearing surfaces on the spindle and cups and balls, unless the crank arm is well supported; that's why methods and tools that press out the cotter pin are the first choice. Once you get out the hammer it raises the risk to old components that are hard to replace.

These cranks from hell were a nightmare for me until I read this post:

http://www.bikeforums.net/classic-vi...ter-press.html

Since using this tool I am 3 for 3 successful removals. Before I was good about 1 in 3.

And yes, the grease is old, probably hardened and useless. In my opinion the crank takes the most stress of any part on the bike and I want everything in this area lubed properly.

Ain't nothin' to it but to do it! :thumb:

I am going to have to make a tool now. Thank you for the link!

I have taken apart 2 sets with good results. I think you have to. Grease gets old and drys out. I also have to admit, that I am the type of person that would worry about it, if I did not take it apart and inspect, clean and grease myself. I also purchased new bolts both times before I started. I also soaked them with penetrating oil for a couple days before I started.

When removing the cotter, with a tool or hammer, keep the loose nut on the cotter to avoid damaging the threaded part. When it is loose, remove the nut, take the cotter out, continue with disassembly. Cotters are soft, it is easy to squash the threads.

Just do it. It's always a good (or bad) experience with these guys. Case in point, a 3-day fight I had with this one on my Raleigh Sport. Guess who won? lol :cry:
http://i63.tinypic.com/21bj9lf.jpg

I might consider that a tie.

Pretty much. lol

Or just use a c-clamp & socket.

This is my tool. I use an old axle spacer for a "socket".

Look at this video by RJ the bike guy:

. . . and be sure you are getting the right size. They come in different diameters, different lengths and different angle of the flat part. The diameter is the absolute critical dimension. Coter pins are soft metal, so if they are too long or the flat is wrong, you can (usually) fix that with a dremel, cutting attachments, and grinding attachments. Takes patience, but I've made it work, and I am nowhere as mechanically gifted as many here. And do0n't ask me how I found all of this out. :mad:


BTW, I hate cottered cranks. Only my Eroica bike has them, and only because everything is spinning well and I don't want to mess with it this close to the ride. But I already have the cotterless replacement crank and BB in hand, and they will go in very soon after I get home.

I have a Raleigh Sports also that I will be rehabbing in the near future. Beware.....the head tube bearing assembly has about 50 little loose bearings that will spill out everywhere if you don't use caution when you remove the top race and fork. Ask me how I know. :eek: