Meet my new arch nemesis. I need to change the crankset on my 40 year old bike but this bolt says "haha FU".
I have tried leaving penetrating oil on overnight twice. I don't have a way to apply high heat, but I let my heating pad give it a go. I have been lefty-looseying the poop out of this thing.
Before I give up and go to my LBS, my stubbornness decided I should post here first in case I am doing something wrong or there is another trick to try (this is the first bike I've ever worked on)
by Savings-Sympathy-719
22 Comments
Using a breaker bar? Or trying to manhandle it with a 5″ handle 🙂
Apply more penetrating oil. Go to harbor freight and buy a small breaker bar and 1/2” to 3/8” adapter (or whatever your socket is). Or if you’re cheap, a section of pipe that will fit over your ratchet tool. Put your socket on it and remove it with the breaker bar.
Impact gun?
What wrench are you using? Could you get it in a better position to apply more torque or put something on it to make a longer lever? You could also apply heat by pouring a pan of boiling water on it if you don’t have a torch or heat gun.
I can usually get them by putting the wrench just anticlockwise of the crank and squeezing then together in my hands but sometimes more extreme measures are required.
I had a stubborn crank bolt and the solution I found was to put the pedal against some wood on the floor and then stand on the breaker bar. There are some youtube videos about this if you want to give it a try.
If that does not work, maybe carefully hit it with some PB blaster and if all else fails some very gentle heat. I would only resort to these if all else fails due to it being in close proximity to the bb and frame.
Good luck!
Would knowing that it’s a nut change your approach? Never had one of those nuts put up much of a fight.
Longer wrench, if using a socket wrench slide a metal tube (i use a cut section of old mtb handlebar) as a breaker.
Reverse threads,
Butane torch, plumbing supplies have them and they come in handy in winter. Work the nut at the same time.
Easy solution- propane torch for soldering plumbing. Heat it up gradually and try undoing it every so often.
Destructive solution-If you won’t be using original cup and cone BB you can always get grinder/hacksaw and cut shaft off just behind crank arm. Warning-hacksaw will take forever-grinder with cutting disc is way better.
Are you sure it’s not a reverse thread?
Securing the crank makes this a lot easier – I use a toe strap to strap it to the chainstay. Add leverage by sliding an old straight handlebar (or some kind of pipe) over the ratchet handle. Guaranteed to come loose with just your body weight.
Not to put you off but you’re likely to have a much worse struggle removing the bottom bracket – it might be worth paying a shop to swap the parts for you
Keep at it. It’ll let loose.
Penetrating oil is good. Keep doing that. Also, as others have said, increase the size of the lever arm you are using to wrench this, use a breaker bar. If you don’t have the newtons, get more meters.
Also, what tool are you using to wrench this? If you are using a socket, put the socket on the bolt, and hit it with a hammer. Just, smack it. If this thing is fused together through corrosion, you need to try and break that bond. A good smack with a hammer to a well fitted socket should do the trick.
Also, heat is your friend here, or rather, temperature. Hot, cold, hot, cold, will loosen this up. Heat guns are not expensive, like $20, and super useful outside of the bike world. $20 for a heat gun is probably cheaper than having your LBS extract this.
Anyway, use these techniques in combination: longer lever arm, penetrating oil, time, percussion, heat/cold, and just keep at it.
This is what the LBS is going to do. There isn’t like, a secret to this. Just keep trying.
Lots of good info here. It can also be helpful to zip tie the crank to the chainstay so you’re not fighting the rotation of the bottom bracket.
More oil, a thin walled socket and the longest breaker bar you can find might work; the bar is just a non-ratcheting socket holder. If the bar handle is long enough, you can safely place a long section of pipe over it for max leverage. Be paranoid and wear
safety glasses.
Heat means a small propane torch, the heating pad won’t work. Conventional wisdom is that the bolt expands, but the nut expands more because its diameter is slightly larger than the bolt. I have used a torch to loosen stubborn threads several times.
It’s always possible someone incorrectly used red Loctite on this, in which case you _must_ use heat to free it.
I am concerned that an impact wrench might break something; try the local bike shop before you resort to power tools.
It helps that you have applied the penetrating oil, I think you’re on second base or at least the shortstop, keep flooding it in there. What’s left is a matter of breaking the locked threads.
This is an axel nut not an axel bolt, so much care should be taken with the initial force applied. This design is more susceptible to getting rounded on the hex corners, as the threads are aboutdouble the diameter of the threads being turned with the more common bolt.
Get a racheting socket wrench with a long of an extension handle that you can get, and extend it with a pipe. Apply pressure over the socket end while impacting the extension pipe on the wrench, with judicious (not max) force, counter-clockwise; ball peen or deadhead mallets are good for this. Get a feel for the level of impact force required to loosen this, even by an increment of a turn it might take 3-4 careful taps, afer which it should more easily the rest of the way off.
Spit on that thang
Not oils are the same.
Artic Hayes crack it freezing oil or similar is best in my experience for this type of thing
Wait! Could it be a left hand thread? LEftie tighty / Righty Loosey?
Tighten it a bit first, then undo. Breaker bar will get the job done though.
A new bike. 😎
Need to eat some Wheaties.