Bicycle Mechanics - loctite?

OK I've got some clunks coming from my driveside crank where it interfaces with the bottom bracket. Tightening the retaining bolt gets rid of the clunk but the problem is that the bolt works itself loose. I've read up on it in the barnett's manual and it mentions using loctite to rectify this kind of a problem. I was wondering what you folks thought of this. Should I apply it between the crank and the bottom bracket or should I apply it to the retaining bolt? Most importantly...will I be able to take it all apart again if I ever need to? I want to fix the problem but I don't want to lose the ability to take all the parts apart when needed. By the way it is Shimano 105 splined BB and cranks circa 1999

There are quite a few different strengths of Loctite. Some of them will be just enough to keep your bolt in and still be pretty easy to remove if applied sparingly and others will be permanant. One of the weakest strengths should be enough to keep the bolts in.

Blue loctite = removable
Red loctite = permanent

On square tapered BB If the crank was actually working itself loose enough to clunk, the crankarm will probably be damaged and will continually work itself loose even after being tightened. Don't know if this also applies to splined BB as well.

OK I've got some clunks coming from my driveside crank where it interfaces with the bottom bracket. Tightening the retaining bolt gets rid of the clunk but the problem is that the bolt works itself loose. I've read up on it in the barnett's manual and it mentions using loctite to rectify this kind of a problem. I was wondering what you folks thought of this. Should I apply it between the crank and the bottom bracket or should I apply it to the retaining bolt? Most importantly...will I be able to take it all apart again if I ever need to? I want to fix the problem but I don't want to lose the ability to take all the parts apart when needed. By the way it is Shimano 105 splined BB and cranks circa 1999
Are you applying the correct amount of torque on the crankbolt? 25~35 ft-lbs is quite a bit, and difficult to achieve without a torque wrench. If you don't have access to one maybe a quick trip to your LBS and ask, with big puppy dog eyes, if he would please help you with your problem and properly torque your crankbolts.

If you do use blue Loctite on the crankbolt, do not use it on the splines of the bottom bracket or the crankarms. But again I emphasis the need to have the crankbolts torqued properly. If they aren't, every time the crank works loose, it's destroying the splines in the crankarms, and soon you will need new ones!

Any advice on getting the proper torque quick and dirty without going to the bikeshop?

Any advice on getting the proper torque quick and dirty without going to the bikeshop?
Yes, buy a torque wrench! It will be extremely difficult for you to estimate the necessary torque to apply if you've not done it before. Are you willing to risk the possible harm to your (expensive) crankarms to save a few bucks? Many shops will do it for little or even free because it's easy (for them) to do. And it might even earn them a customer!

I've NEVER had a splined crankarm come loose and I don't use Loctite!

Blue loctite = removable
Red loctite = permanent


Heat will loosen the red loctite.

Heat will loosen the red loctite.
so will more force. only if the head is small on the bolt will the locktite make it impossible to not turn.

Any advice on getting the proper torque quick and dirty without going to the bikeshop?


Simply tighten until your eyes buldge. Without a tourque wrench, the proper amount of pressure is just short of a nosebleed.

You can use blue LocTite on the bolt. Never use LocTite on a tapered fitting, ie bottom bracket / crank.

Jerried up a cheater bar to get more torque in there. After 10 miles things seem to be holding together. Thank you folks! It was not necessary to use loctite. PHEW! I don't like the thought of that stuff on the "good" bike.