EnsitMike

Trying to get a crank lock nut off that is completely rusted on. Soaked in liquid wrench then went and bought PB blaster and let soak for 12 hours followed by cheater bar and it didn't budge. Anything else I can do?

rpenmanparker 

Instead of the cheater did you try to squeeze the crank arm and wrench between you palm and fingers? Lots of torque generated that way. Otherwise an impact wrench might be necessary.

RoadTire 

My boys moved from LR and PBBlaster to 1/2 ATF and acetone, and haven't gone back. Also they can remove bolts with a impact wrench. I guess it's not so much the overall torque it's the constant hammering that breaks those bolts without twisting the head off. You might be able to get a local small shop to do that for you.

SJX426 

Kroil would be another option. I found it very effective along with heat or freeze.

peterw_diy

CRC Freeze Off worked for me where PB Blaster failed.

Kopsis

+1

Back in my days of rebuilding air-cooled VW engines, getting the nuts off the exhaust manifold studs was always an adventure. The nuts were invariably seized, and often rusted away so bad that you couldn't get a wrench or socket to fit. I learned that putting a small cold chisel on the flat, angling it about 45deg clockwise, and whacking repeatedly with a BFH would often be enough to break the nut loose. I wasn't generating that much torque this way, but combined with soaking in penetrating oil and heating with a propane torch, the shock from the hammer blows was enough to break the rust.

In this case, since you can get a socket on the nut, take the bike and a box of donuts to the nearest auto shop (or LBS if you're confident that they have a set of air tools) first thing in the morning and they'll likely have the nut off in under 5 minutes.

Slash5

Every workshop should have a manual impact driver. Cheap and work great.
Impact Screwdriver | eBay

FBinNY 

Often an air impact wrench will free bolts that don't move otherwise. Buy a 14mm socket, and bring it to your auto mechanic. Remind him to wear goggles because the socket may explode if the bolt doesn't move.

JOHNinIL

Here read this over for ideas 10 Tricks to remove that Stuck, Seized, or Stripped Bolt/Nut | Eastwood Blog

my goto at this point would be a propane torch

leob1

Any competent mechanic will use a socket designed for use with an impact wrench. And those are usually six point instead of twelve point sockets. There is no need to bring your own.
Be prepared for the head to shear off the bolt. If that happens you'll need to buy a new BB.

reptilezs

impact sockets do not fit in the crank arm. they are too fat

FBinNY 

Yes, any competant mechanic will prfer to use an impact socket,but they don't fit. The reason why I suggested buying your own, is because that same mechanic won't want to sacrifice a standard socket to the job.

There is the risk that the bolt snaps, but I've never seen that happen. However, if the bolt does snap, it will allow the crank to be removed and get past that hurdle.

If the BB is otherwise in good shape the bolt can be drilled through and the last of it removed with a tap. This usually isn't warranted because BBs aren't that dear, but I've done it to save a vintage Campy track BB spindle.

So the OP has a choice, continue to struggle, or risk the price of a 14mm socket, and possibly a BB that wouldn't have been usable anyway. Doesn't seem to too tough to decide, but that's just me.

davidad

I use a 4 pound maul for those types of fasteners. Boilermaker habits die hard. You will need a way to immobilize the crank.

Reynolds 

A 6 point 1/2" drive socket + sturdy handle + cheater bar will take out the bolt or shear it.

FBinNY 

Don't forget that this will call for two cheater bars, the second one slipped over the crank, or the opposite one.

A 2' wrench or cheater bar won't do you any good if you're holding onto a 7" crank to keep it from turning.

The beauty of an impact wrench is that it works against the crank's inertia.

Reynolds 

^ That's right, you should remove the pedal and slip a pipe over the crank arm.

EnsitMike

Update: Thanks for all the help guys. I ended up using some mapp gas with a small sand filled sledge and it worked. I had to heat the bolt and then douse it in water for it to work though-- straight heat didn't do the trick. The idea was rapid expansion changes may crack that seal.


The downside is I stripped the threads on the driveside using the crank puller. Project for another day I guess

loimpact

Out of curiosity......Was this one of the bikes you have listed?? (Hopefully not that SuperSix)

Amazing how some fasteners can just lock up like that.

EnsitMike

Oh no, it was my girlfriends neglected schwinn le tour.

3alarmer 

....has worked here in a number of hopeless situations. Worth trying for sure.

dscheidt

the OD of my snap-on sockets is less than that of many cheap sockets. They're thicker than my Snap-on plain sockets, of course, but not a whole lot. Safety googles are good idea, regardless.

Impact wrenches are under-appreciated by bike mechanics. They're exactly the right tool for removing things like free wheels, for instance.

reptilezs

i use my impact daily. my main gun is a milwaukee 12v. it is great for removal and stripping stuff down. i do not use it for install unless it is a larger fastener. also have air powered in 3/8 and 1/2 but those do not get used often

OldsCOOL

Especially if the bike is layed down on a big vise and clamping far side crank arm in to completely secure it. Yup that cranky bolt will come loose.

rootboy 

+1