Cottered crank removal
 

Just thought I would pass along a cotter pin removal technique thats been working quite well for me.

I am one that has a minimal of tools and no work stand. I tear apart and rebuild lots of bikes. I make due with what I have and can take apart clean and rebuild a bike in short order. BUT, cottered cranks were always a problem. I have struggled for hours removing stubborn cotters.

What I have been doing lately with much success is the following:
I remove the wheels from the bike. Prop the bikes BB on top of a gal. paint can. Its what I have on hand and is a good height.
The crank arm I want to remove is hanging free off the side of the can. I remove the cotterpin nut. Spray PB Blaster, penetrating oil spray, into top of cotterpin area. Let it sit for 10-15 minutes. With the BB supported on the paint can I take a hammer and take 3-4 good hits to the cotter pin. The cotterpin pops loose.

It's worked on the last three bikes I have worked on. All were in the 40 year old range. Give it a try if you don't have a cotterpin press. I think the PB Blaster really gets into and around the cotter and gives it a certain amount of slip when you hammer.

I have been having a lot of success with the PB Blaster on stuck stems and seatposts also. Its good stuff.

I spray PB Blaster into empty, 2oz. Tri Flow drip bottles. Makes a can of PB last forever, puts the PB precisely where you want it, and in most cases, makes it easier to apply.

The thing about removing cotters is that nothing works EVERY time. :(

I have a cotter press but it sometimes just mushrooms the cotter.
- I just had to drill out a cotter that I personally installed just 3 or 4 years ago, and that was in spite of using both PB-blaster AND a torch.

PB blaster is great stuff though... Warming the crank arm a little seems to help too.

Excellent....I found a 24" section of heavy 2 1/4 Galvanized pipe I use as a back up to support the crank and BB. Nice to hear a paint can works too!

I have had good success with a c clamp and a socket. Put the socket over the exit end. Place the c clamp on the other end of the pin and the end of the socket. Slowly close the clamp.. The pin is pushed into the socket

[QUOTE]Impact Hammers work everytime....soooo it may eat a few spindles but hey....the cotters out :rolleyes:

[QUOTE=Velognome;15307839]Don't say every time. I've flattened many a cotter with them.

you stopped?

^ I finally bought a BikeSmith press.

- But the results are almost as checkered, insofar as removal goes - at least when the cotters are really wedged-in tight.
However, installation with a real cotter press is like a little piece of heaven, compared to the platen and claw-hammer method. Easier on the spindle too.

So true....Haven't tried the press, can't imagine it any more productive than a C clamp and socket. Have only gone to the impact hammer when all else fails and it's usually ugly but effective in the end.

+1. This is how I've done it, except I like to just loosen up the nut holding the cotter pin a couple of turns, like a 1/4 of an inch maximum. Then I thread another nut on, so it if flush (or slightly proud) of the cotter threads (this gives a bigger surface for the c-clamp to mount to). If you have them, throw a couple washers in between the nuts and tighten the whole stackup. This helps stabilize the threaded portion of the cotter pin and prevents it from bending at the weakest spot (which is usually somewhere in the threaded portion). Once the cotter pin has broke free, you take off all of the nuts/washer arrangement except for the nut flush to the end of the cotter pin.

I on the other hand have had no luck with removing those little cotter pin bastards that come from the deepest darkest bowels of satans unholy *******! and I have tried all the above and aforementioned removal techniques! :mad:

+1
Use a Machinists C clamp (finer threads)
The day before, start applying PO every few hours.

^ don't think that they come out intact...maybe once or twice...more often squashed, drilled mashed little bits of steel from...how did you say, " the deepest darkest bowels of satans unholy *******" Success is measureed simply by the seperation of the the crank from the spindle in what ever means possible.

I have a small arsenal of cotter tools including the bikes Smith press, two things from harbor freight, a bench vise, and a drill press vise. The drill press vise is probably the best. The bike Smith tool, ironically, is good only for low to mid range cranks. It is not good for high end cranks.

I'm a C Clamp and Socket kind of guy.

Or I was a C Clamp and Socket kind of guy at one, short period of time.

I've only removed 1 cottered crank so far, but I used a cheater method, without really thinking about it. Besides the obvious, like penetrating oil & loosening the nut a little, I used a hardwood 2x2 to drive out the cotter pin. As in sit the 2x2 directly on the cotter pin, then whack that good with a hammer. It's a lot better than aiming & hoping, if you know what I mean. :D ;)

Not once have I ever had this not work, and im a professional mechanic... removed hundreds and hundreds of cranks

http://farm6.staticflickr.com/5001/5...bed2667b_z.jpg

Showoff! :D It kinda matters how often you go around removing cottered cranks, I guess. ;)

hAVING THE PROPER TOOLS MAKES EVERY DIFFERENCE IN THE WORLD. Sorry about the caps lock... haha. but that applies to everything in the world as far as im concerned.

the right tools = easy job = no damaged parts (body or bike)

I may have mushroomed a few cotter pins but they always come out.

Ditto. I've only once had my BikeSmith cotter pin press fail me on removal and that was my own fault, I think. I should've been paying better attention - I simply squashed the crap out of the pin when it began to disengage crookedly.

I used an older 2-prong Suntour freewheel remover in place of a socket. The two prongs straddled the crank arm, and it seemed a little more stable than a socket.

In lieu of the proper tools, I have set up the bike in a stand and then support the crank arm with a pipe against the floor. This is to prevent damage to the bearings when I give this thing a whack. To whack it, I use a large brass drift about 3/4" in diameter and 1 foot long. But before that I apply a bit of Kroil, which I allow to soak in for a few hours. One good whack is all it takes with a 5-pound sledge, 3 or 4 with a claw hammer. The brass drift reduces damage to the cotter pin itself; no mushrooming really but sometimes the top thread has to be touched up. These days I run a nut onto the thread before whacking it so I can chase the thread out nicely.

+1. Every time I come across one of these it's like a replay from the movie Moby Dick when Ahab cries out in despair, "O ye damned whale (cotter)!"

For those interested in solutions used to free stuck parts, Machinist's Workshop Magazine discussed solvents used for freeing frozen parts. They found in freeing a frozen part:

Product / Average load / Price for each fluid ounce

None / Required 516 pounds of force to free / (no cost)
WD-40 / 238 pounds / $0.25
PB Blaster / 214 pounds / $0.35
Liquid Wrench / 127 pounds / $0.21
Kano Kroil / 106 pounds / $0.75
Auto Transmission Fluid (ATF)-Acetone mix / 53 pounds / $0.10

Of course, if you use the ATF-Acetone mix, be really careful around painted items. I like Kroil the best for that reason. I use a small Berzomatic torch and Kroil for really stuck stuff.

For cotters, I have the Bikesmith press.