justinzane

I've, with a mixture of inattention and brute force, stripped the threads off a really stubbornly stuck drive-side JIS square taper crank. So, I tried the heat gun approach, but presumably since this is a super cheap steel crank on a steel spindle, the thermal expansion was the same on the spindle as on the crank, so that failed.

Then I tried the loosen-the-bolt-and-ride method. Even after maybe two miles of pedaling the oddest squares I can manage, bunny hopping, riding standing on washboard gravel, etc., the crank is still hopelessly tight. Next up, I tried using a mallet and bar to hit the inside chainring at various spots from through the frame. While the crappy steel rings got slightly bent, the arm is still sock like it was welded on.

Since I do not have any electric or pneumatic cutter to simply slice the f!#@$ng arm off, I'm kinda stumped. I'm planning on replacing the 68mm English bottom bracket and I intend to deposit the crank directly in the bin, but I do not want to damage the frame.

Guidance and inspiration are needed!

SOLVED: Thanks @GravelMN

JohnDThompson 

Penetrating oil, and a two-arm gear puller or Jacobs chuck remover wedges between the crank and the BB shell.

GravelMN

Check with any tool supplier or automotive shop for an appropriately sized "pickle fork". They are tapered two-tined forks designed for just such a predicament. Sometimes you have to use two from opposite directions driving them in toward each other to get maximum wedge effect.

Deontologist

You said you loosened the crank retaining bolt. Sounds like some threads still exist. Have you tried a crank puller such as the one by Park Tool? Very effective.

Ayers

Like suggestion number two above, the two jaw puller will quite likely work. Now, sometimes it's difficult to find two purchase points 180 degrees apart on the crank drive side for the puller arms, but if the crank is scrap metal, a little grinding should offer enough of a notch to get both of the arms firmly around the center section and well hooked on the backside.

Then, and this is the nugget here, apply good and strong pressure with the puller, and while it's still under a lot of tension, hit the center hub of the crank arm perpendicular to the spindle shaft. Right on the side. Hit it like you mean it. That's a trick to applies to loosening any tapered installation whether on a car, bicycle, or anything. With the puller under a good serious bind, the sharp whack of the hammer will jostle the taper and they usually pop off into the floor at your feet.

(I'm a guy who worked on many, many car suspensions with tapered fittings on ball joints and tie rod ends. That hammer whack is the secret. In 20 plus years of doing it, I never found a single one that wouldn't pop loose that way).

justinzane

Bada Bing!!! Local auto parts store had a pickle fork. Two minutes with a mallet and the fork, the old crank popped off! THANKS!

exmechanic89

Glad you got it off. I somehow stripped out the threads in my non-drive alloy crank arm a few days ago, tried everything to no avail and ultimately had to cut the arm off with a hacksaw. What an enjoyable process that was.

justinzane

Oy! I'd die happy never having shared that particular experience. You must have been so friggin' thrilled when the arm finally fell off.

exmechanic89

Yeah it was a real joy, lol. I had to have my wife hold the frame still in the stand while I hacksawed away, then banged on the arm with a hammer after going most of the way through with the saw. Finally it was off. Oh and lot's of cursing involved too, lol. I'm convinced the factory put the arm on too tightly, as I used the crank puller correctly and have pulled plenty of them before.