[mizunole]

Any suggestions on removing an over tightend crank arm bolt off an ISIS crankset?

 

[flipnidaho]

If the bolt head is not stripping

Try using a long lever to give you extra leverage. I have a 3 foot length steel pipe that I slip over the handle of whatever tool I need leverage on. Just make sure you are turning it the correct way....

 

[mizunole]

Try using a long lever to give you extra leverage. I have a 3 foot length steel pipe that I slip over the handle of whatever tool I need leverage on. Just make sure you are turning it the correct way....

Bolt head is stripped (good idea though)

 

[Gevorg]

Did you try a bolt extractor? It comes as set of drill bits and extractors.
You need to drill a small hole in the center of the bolt and use bolt extractor (basically self tapping left hand big screw) to remove it. I used it to remove bolts with stripped and broken heads. Most hardware stores should have it (True Value, Ace Hardware etc).

 

[mizunole]

thanks

the bolt extractor thingie worked

 

[FrankinMich]

Crank bolts

the bolt extractor thingie worked

When you remount the crank arm with a new bolt I hope you grease the threads and use a torque wrench!

 

[hugh088]

Crank bolts

When you reinstall use copper based thread compound. Grease is for bearings, thread compound is for ,,,well you figure it out.

 

[mizunole]

yup

 

[FrankinMich]

When you reinstall use copper based thread compound. Grease is for bearings, thread compound is for ,,,well you figure it out.

In every bicycle maintenance book I have ever read (I currently own three such books, all by different, expert authors) they instruct you to grease the threads on cartridge bottom brackets or external bearing cups. One book suggested teflon plumber's tape as an alternative. None of them mentioned anything about using thread compound. All metal parts tend to "bond" over time, especially when water gets into the joint. The use of grease mitigates this effect and makes it easier to disassemble things. That is why the pros recommend its use on most threaded joints on a bicycle (notable exception: disc brake rotor mounting bolts). Properly torqued, a joint with greased threads will not loosen.

My concern with using thread compound would be when you try to remove the bottom bracket. The thread compound will make this process much more difficult. You could quite possibly damage your bottom bracket, external bearings, or even your frame while you are "wrenching" on things.

 

[hugh088]

Thread compound

First notice I said copper based thread coumpond not loctite or a thread locking compound. What is the copper based thread compound, grease with copper flakes in it. There are other similar compounds that use other metals but copper is the most comon for most uses but you can get lead, zinc, and if you happen to have a atomic power plant nickel is popular. Why is that better the grease? Because the microscopic copper flakes are compressed between the threads and form layers of soft flakes between the harder metals of the threads. One of the problems of just using grease is that the grease is extruded as the threads are compressed together. Someone might jump in and say the grease keeps the balls in bearings from touching the races so it should not be extruded. That's true in the dynamic nature of a bearing but is not the case in the static nature of a threaded connection. This copper does several things, one of which is to make a metal to metal seal the keeps water out. A much stronger seal then grease, The most important feature is that when you remove the thread the compressed flakes shear rather then the metal of the threads galling on each other. You mention that some books recomend using grease, true grease is better then nothing as it fills the roots of the threads and can help prevent water getting in but the thread compounds do that and more. You mentioned plumbers tape. Great, it works just like the copper in that it forms a microscopic layer between the surfaces of the threads that will shear and fills the roots. To tell the truth I have also used it on the bottom bracket of my bike, mainly because it's a little neater. I have also used teflon tape on seat rails to quiet squeaks. Bottom brackets and most other threaded connection will do better with the copper based thread compounds rather then grease. There are exceptions suchs as bolts that must resist a rotational dynamic fouce such as suspension pivot bolts here the manufacturer will often call for blue loctite.

Chris

 

[FrankinMich]

Thanks

First notice I said copper based thread coumpond not loctite or a thread locking compound. What is the copper based thread compound, grease with copper flakes in it. There are other similar compounds that use other metals but copper is the most comon for most uses but you can get lead, zinc, and if you happen to have a atomic power plant nickel is popular. Why is that better the grease? Because the microscopic copper flakes are compressed between the threads and form layers of soft flakes between the harder metals of the threads. One of the problems of just using grease is that the grease is extruded as the threads are compressed together. Someone might jump in and say the grease keeps the balls in bearings from touching the races so it should not be extruded. That's true in the dynamic nature of a bearing but is not the case in the static nature of a threaded connection. This copper does several things, one of which is to make a metal to metal seal the keeps water out. A much stronger seal then grease, The most important feature is that when you remove the thread the compressed flakes shear rather then the metal of the threads galling on each other. You mention that some books recomend using grease, true grease is better then nothing as it fills the roots of the threads and can help prevent water getting in but the thread compounds do that and more. You mentioned plumbers tape. Great, it works just like the copper in that it forms a microscopic layer between the surfaces of the threads that will shear and fills the roots. To tell the truth I have also used it on the bottom bracket of my bike, mainly because it's a little neater. I have also used teflon tape on seat rails to quiet squeaks. Bottom brackets and most other threaded connection will do better with the copper based thread compounds rather then grease. There are exceptions suchs as bolts that must resist a rotational dynamic fouce such as suspension pivot bolts here the manufacturer will often call for blue loctite.

Chris

Chris,

Thanks for the lengthy, but very informative, response. I learned something new and useful today! Can you suggest any brands of copper based thread compound that I might buy? Also, where can you usually purchase this stuff?

Thanks!

 

[hugh088]

Thread compound

Never sieze or copper-cote. While I mentioned I was not talking about Loctite I believe they also make copper base thread compound. The local auto parts store will have one of these or something similar. I have had a tube for the last 15 years.
Chris

Chris,

Thanks for the lengthy, but very informative, response. I learned something new and useful today! Can you suggest any brands of copper based thread compound that I might buy? Also, where can you usually purchase this stuff?

Thanks!