Bicycle Mechanics - Can't remove crank bolt. This is a right hand screw??

I'm trying to remove this Shimano crank bolt of the late 1990's bike and I'm afraid to put too hard.

Question:

I'm assuming this is a regular right hand screw and I turn it counterclockwise to looosen it??

See photo

You are correct. Hit it with a little PB Blaster (http://blasterchemical.com/display.cfm?p=50003&pid=4) if they sell that near you, that stuff is ridiculous.


I'm trying to remove this Shimano crank bolt of the late 1990's bike and I'm afraid to put too hard.

Question:

I'm assuming this is a regular right hand screw and I turn it counterclockwise to looosen it??

See photo

I'm trying to remove this Shimano crank bolt of the late 1990's bike and I'm afraid to push too hard.

Question:

I'm assuming this is a regular right hand screw and I turn it counterclockwise to looosen it??

See photo

Crank fixing bolts are all right-hand threaded.

bigger muscles

I'm trying to remove this Shimano crank bolt of the late 1990's bike and I'm afraid to push too hard.

Question:

I'm assuming this is a regular right hand screw and I turn it counterclockwise to looosen it??

See photo

No photo but not needed...standard threading so if you're using a short handled wrench just try a longer one, or put an extension on your wrench, for more leverage...I can see not pushing too hard when tightening, but loosening?

It is possible to wrench off the top of the bolt, but if so it can be drilled out with some
care and the remnant removed, if the BB is worth it. Probably not. Next assembly be
sure to put a bit of lube on the threads. Now maybe some twit put locktite on the
threads. No way to know, but locktite breaks down at ~400F or so, ie a heat gun, but
the risk to the paint job is extreme. A torch to the bolt head with a tiny flame might
work, but would be better to just torque the d--n thing out and chunk the BB than
risk the paint.

You are correct. Hit it with a little PB Blaster (http://blasterchemical.com/display.cfm?p=50003&pid=4) if they sell that near you, that stuff is ridiculous.

He should also try a good P-handle 8mm, at the appropriate angle to give maximum leverage first.

Now maybe some twit put locktite on the threads. I don't know if even red loctite would lock up such a small thread so thoroughly. I have a bottom bracket sitting on my desk right now, and I had covered most of the thread with red loctite to stop it from clicking, and it came right out, and it's a much larger thread surface for the loctite to stick to. I think seizure is more likely than loctite to be causing such a problem. This is why you should use antiseize compound before installation.

Excessive heat could soften the aluminum crank, and a small amount of heat is not likely to heat anything much because the aluminum is an excellent conductor of heat and offers a large cooling surface.

I think the only solution is to try to put a little Liquid Wrench in through the corners of the inside of the crank arm or through the serrations on the bottom of the bolt head (between bolt and crankarm), then leave it overnight for the stuff to soak in, then ensure you have a well fitting wrench which won't round off the bolt, then use a breaker bar such as a metal tube around the handle of your wrench and another around your crankarm for extra leverage. Then, as they say, shoot or get off the toilet, there's nothing else to do except drill it out if you can't unscrew it, so go for it with all the leverage you can manage.

the only tough crank bolts that i have had to crack were from isis cranks. these were from bikes built in a factory. bolts were greased from the factory so no prob there. just needed a big wrench and muscle. cracked that bolt right out.

He should also try a good P-handle 8mm, at the appropriate angle to give maximum leverage first.

A cheater-bar (hunk of pipe that fits over the handle of the wrench and extends it for greater leverage) can work wonders. If it breaks? It may have been cross-threaded or such.

+1 for the PB Blaster. Let it soak overnight. :thumb:

Panthers007's suggestion of a cheater-bar will work. Most Allen keys are too short. You can put a long adjustable wrench on the end of your allen key. It will work.

The hole in the end of the handle of an adjustable wrench is the go, I find

Make sure you tap the center of the head of the bolt with a punch(hit by a hammer) or a nail first-tap it pretty hard-then wait a few minutes. Spray it with your penetrating oil first.

Once you decide to actually wrench it off, hit the end of the wrench with a hammer, or a 2 x4 or whatever. -with the socket preloaded firmly in place-The sharp blows will jerk it loose. Just trying to power it out is more likely to snap it off.
1)Penetrating oil
2)Hit it with a sharp series of metal to metal raps-supposed to loosen the corrosion etc binding the threads
3)Hit the end of the wrench with a series of sharp blows until it loosens.
4) Could use a hand impact to get the same sharp rise in force as "whapping" your wrench.

Charlie

Make sure you tap the center of the head of the bolt with a punch(hit by a hammer) or a nail first-tap it pretty hard-then wait a few minutes. Spray it with your penetrating oil first.

Once you decide to actually wrench it off, hit the end of the wrench with a hammer, or a 2 x4 or whatever. -with the socket preloaded firmly in place-The sharp blows will jerk it loose. Just trying to power it out is more likely to snap it off.
1)Penertaing out
2)Hit it with a sharp series of metal to metal raps-supposed to loosen the corrosion etc binding the threads
3)Hit the end of the wrench with a series of sharp blows until it loosens.
4) Could use a hand impact to get the same sharp rise in force as "whapping" your wrench.

Charlie

Banging on a wrench is not a good way to remove a nut or bolt. If you have to do that, you really need a longer wrench to get more leverage.

The proper way to use a wrench to tighten or loosen nuts or bolts is to use both hands - one on the handle and one on the head. Pull with one hand and push with the other hand with equal and even pressure. This minimizes the side forces on the nut or bolt, and maximizes the torque twisting the nut or bolt tighter or looser. Minimizing the side forces makes the nut or bolt easier to install or remove, and reduces the chances of damaging the threads.

Banging on a wrench does none of that, and also is all too likely to twist the wrench around the axis of the handle which could easily round off the bolt head or the nut.

+1 concentrate on making all the force in the right direction.

Try an impact driver. This can remove the most stubborn of corroded bolts. Sears sells for a modest price. I use these when working on old motorcycles that have been out in the elements and neglected for decades.

http://www.toolnet.co.za/images/47641.jpg

Achoo- hitting the handle of the wrench is a poor man's impact wrench-like I mentioned in #4-and as MikeWinVa pictured. Of course, you have to support the head of the wrench-I assumed the OP had the experience to not just wang away.I specifically mentioned preloading the wrench so it wouldn't round the head.
A longer WRENCH IS NOT THE ANSWER for a small bolt like that-it will twist it right off. You need a very sharp, short rise in force-a hand impact wrench-which most folks don't have-works ok-a pneumatic impact is usually too much for too long and it will snap the head off just like your longer wrench.

He needs a very sharp, very short twist-an impact wrench of hitting the handle of his wrench while supporting the head and preloading(making sure the socket is in firm contact) the wrench before hitting it. A helper-3 hands- sure helps-

A longer wrench on a small bolt IS NOT THE ANSWER-TAP THE HEAD OF THE BOLT(metal to metal to vibrate the corrosion and crack it)-USE PENETRATING OIL, AND USE A HAND IMPACT OR THE HIT THE WRENCH METHOD.

The longer wrench will snap it off.
Charlie
PS He needs to crack/loosen the binding corrosion-hence the emphasis in setting up a vibration,and the penetrating oil allows the gunk to slide around once it is cracked.Always hit the center of the head -(metal to metal--punch is good)- of an old bolt before wrenching it
PSS I use an EBAY Snap On hand impact for this purpose, but occasionally I still use the hit the wrench method.

The longer wrench will snap it off.

You don't even know what size wrench he is using. What a ridiculous statement. He could be using a 6" long allen key for all we know. Ideally, he'd get an 8mm hex bit socket and use it with a 12" or larger ratchet. He'll need something of the sort to retorque the crank arm properly anyway. A poor man's hex bit socket can be made by cutting a short section of an 8mm allen key with a Dremel tool and sticking it in an 8mm socket.

There are very few instances where an impact wrench/driver will remove a bolt that would otherwise break using standard methods for removal. Situations like that are rare to non-existant on a bike.

To the OP, my personal recommendation is again to use a hex bit socket. Set the bit in the bolt head and whack it firmly a few times with a hammer to set the bit (important if there is any corrosion or dirt)and "wake up" the threads. Now, using an appropriately sized ratchet, loosen the bolt. Use gloves on your hands to prevent sacrificing some blood to the chainring gods when that sucker finally breaks free.

Yeah, I bet he's using an itty-bitty L-shaped allen-key. The crankbolts are one of the tightest ones on the entire bike and needs the proper tool to remove and install:

http://i42.photobucket.com/albums/e346/DannoXYZ/Cycling/AllenSocketBreakerBar.jpg

Needs at least a 12" handle. Will easily overcome red Loctite without any problems. In the case of severe corrosion, it can even snap the head off the bolt if necessary.

The suspense is killing me...OP, what did you end up doing? What tools were you using? You've got just about everything possible covered so far (other than just using high explosives:D) in the thread now...

joejack-I see you are singing my song-"hit it with a hammer to set the bit and "wake up" the threads-info I gave him in my first post.Hey, glad I taught you something-you can have full credit-along with the credit for snapping it off with a bigger wrench!!

I know that I can put 100 lbs-ft of torque on a 6" wrench-waaay more than it needs or can safely take. That bolt is placed so you can get your whole weight on it.


Occasionally, very very occasionally a really tough bolt will respond to a hand impact if you give it a couple of GENTLE raps in the wrong direction before going back to the right direction with full power hammer hits.Once again, you are breaking the corrosion binding the threads. This takes a bit of feel/practice,so pass on it, but keep it in mind.

If someone posts that he is scared he will snap the head off a bolt,I naturally assume that he has already given it a pretty stout effort. The "get a longer wrench" advice is just telling him to pull harder-we're telling him to pull smarter.

PENETRATING OIL-RAP, RAP RAP ON THE HEAD-HAND IMPACT OR HIT YOUR WRENCH-out it comes.
Or longer wrench, and out it comes, or off it comes.

joejack-I see you are singing my song-"hit it with a hammer to set the bit and "wake up" the threads-info I gave him in my first post.Hey, glad I taught you something-you can have full credit-along with the credit for snapping it off with a bigger wrench!!

Well, you suggested using a nail in the bolt recess. Using the bit itself accomplishes two things at once as I described.

How often do you hear about people snapping the heads off crank bolts? If it was truly a big concern, I would offer some different advice than "try a bigger wrench" but IME and based on what I've read online, it just doesn't happen. I can list for you several bolts (not on bikes but on cars) where you do need to take precaution to avoid snapping heads off. Most of them are in areas where it would be difficult to remove the remaining bolt and where corrosion is very likely. Crank bolts on a bike posess neither of those qualities though.


I know that I can put 100 lbs of torque on a 6" wrench-waaay more than it needs or can safely take. That bolt is placed so you can get your whole weight on it.

I'm assuming you mean ft.*lbs. of torque. Or did you mean 100 lbs. of force? Either way, you are way stronger and have much tougher hands than me. You cannot put your whole weight into a crank bolt because you also must resist any input torque with a counter-torque otherwise the crank will simply spin. A bottom bracket allows one to put all of their weight into it though.



Occasionally, very very occasionally a really tough bolt will respond to a hand impact if you give it a couple of GENTLE raps in the wrong direction before going back to the right direction with full power hammer hits.Once again, you are breaking the corrosion binding the threads. This takes a bit of feel/practice,so pass on it, but keep it in mind.

I would never do this unless it was a thru-bolted assembly or if I didn't care at all about the bolt or the part it was threaded into. Terrible advice, especially for a square taper crank (not that we even know what type of crank we are discussing).


If someone posts that he is scared he will snap the head off a bolt,I naturally assume that he has already given it a pretty stout effort. The "get a longer wrench" advice is just telling him to pull harder-we're telling him to pull smarter.

PENETRATING OIL-RAP, RAP RAP ON THE HEAD-HAND IMPACT OR HIT YOUR WRENCH-out it comes.
Or longer wrench, and out it comes, or off it comes.

Most people don't own good quality tools. That's a fact. The most common 8mm hex wrench that would be owned by a cyclist is either on a mini-tool or part of an allen key set. Neither is sufficient for removing a crank bolt, especially a stubbornly tight one. Crank bolts are unlikely to be severely corroded in place as they are typically steel in steel and the threads are pretty well sealed from the environment. Attempting to use impacts to remove a crank bolt is way more likely to strip the hex recess as the bit becomes angled in the bolt head compared to the chances of torquing the head off the bolt using more leverage. Even if the head did break off, you have very easy access to get at the remains which will likely spin right out by hand. I obviously feel that you are suggested a misguided approach to getting that bolt out.

Joejack- I usually perform the raps on the head with a punch initially, them spray penetrating oil, then re-rap. I want a little time for the oil to penetrate the "cracks" that the raps have created.
If you make sure the socket or allen is in contact with the faces of the bolt, the hand impact, or wrench rap is less likely to round the edges than a long slow high force pull.A biggish allen head like that with good quality steel-Shimano- won't round very readily.

Yes,I can put 200 lb of force or -100 lb ft on a 6" wrench end(but I sure wouldn't in this case). I block the crank arm with anything handy-so it won't move. I weigh 200 with a slight bounce I could get an instant force of 200+ on it. For tricky jobs like that I enlist my son, so the wrench head can be supported and I can get my weight into it.Of course,I never do that because putting 100lb ft might snap the head off. Besides, if I thought brute torque was the answer, I would put a pipe on the wrench or use a breaker bar.

Patience, penetrating oil mixed with raps on the head-repeat,repeat,repeat then a hand impact is the way to go(no hand impact, then the wrench rap with a 3rd hand).Patience...we don't know what tools he has-but my way will work with whatever he has-the oil,rap head, repeat,repeat is more important than the actual rap that breaks it loose-take your time-maybe an hour waiting for the raps and oil to work will get you your best shot.
95/100 the longer wrench will work-the other 5, broken bolt.

We disagree on this one.
Charlie

I'd go for more leverage before hammering your bike to pieces, but if you do I hope you support the other end of the spindle so the force of the hammering doesn't go through the frame. Same for if you use an impact wrench.

You learn something new every day, I guess. I didn't realize there was room for a hammer in a bike tool kit. Somehow I've been struggling along without taking a hammer to my bikes. Not many snapped bolts either.

You do tap a part to get liquid wrench or PB to penetrate but I don't think there has to be a lot of force involved.

+1 for the hammer and impact driver. just removed original DS BB cup from '76 Le Tour.
Hit it on the face 5 or 6 times with hammer. Came out easily with open end HS wrench.

A hand impact-you can get a Snap On-used on Ebay-for $30- is a great tool.The Sears one is fine-works just fine-but the Snap On "feels better" in your hand.Granted it sure as heck doesn't feel $200 good which is what Snap On probably wants for their little hand impact kit.

I doubt the OP has a hand impact, hence my cheapo advice .Of course the right tool is always better, but most folks have to work with what they have. A length of pipe over his wrench is a "longer wrench"- not my first choice in dealing with a bolt in place for 12-15 years.
Patience to let the penetrating oil get in the cracks, and to repeat the oil, tap the head,, oil tap the head, and-getting another set of hands to help-go a long way on stuck fasteners.
The OP was having doubts about applying more force-the little voice in his head was telling him " careful not too hard." I used to ignore that voice and twist away.$30 for a hand impact is a good purchase.

If you're gonna use a hammer, I'd recommend putting the allen-socket into the bolt and tapping on that. Or using an impact-driver. Both methods will spread out the load.

However, using a nail or punch will concentrate the force on a single off-centre spot on the bolt-head. This will create a divot. Where did the metal that used to be in this hole go???

I don't see how the use of a hammer is in any way "better" than using the proper tool (long ratchet wrench). In my 10-years at a shop, I've never ever had to use a hammer on the crank of the tens of thousands of bikes I've worked on. Is the OP going to use a hammer to re-install the crank? Is the hammer going to generate the proper amount of torque? Whatever tool he's going to use to re-install that crankarm bolt properly might as well be used to remove it.

The hammer/metal to metal sharp rap is to send a sharp vibration thru the bolt to crack up the corrosion that is holding it in place and to allow the penetrating oil to penetrate thru the cracks-this is why patience is such a virtue.

I mentioned using a punch or nail because I was thinking in terms of a standard bolt head, not an Allen head.For an Allen just use your allen socket.Some bolt heads are hard to get to-hence the punch or nail.

I'm not from the "get a longer wrench and eat your Wheaties" school of stuck fastener removal.

There is/was a famous motorcycle tuner-Yoshimura-he threatened to fire any mechanic if they snapped off a bolt head and it didn't have a hammer ding on it. He had them hit the head directly with the hammer if possible.

PS Maybe I have reacted a bit too harshly to criticism, if so, my apology.We all tend to think that what worked for us is the best and only way. Sure a longer wrench is easier to modulate even if you don't use it to apply more torque. The OP seemed a bit reluctant to put more ooommmmph into it, so I suggested non ooommmph ways. Hitting the end of a wrench is a bit tricky-blow can sideslip and hit frame etc.But, if you don't have a hand impact, it is a useful technique.