Bicycle Mechanics - Deore Octalink Crank coming loose

I have a Deore FC-510 crankset that continually comes loose. Any suggestions?

It is an Octalink and it is probably an '03 or '04. When a square taper comes loose, I realize that you are pretty much out of luck, short of trying to peen the metal back into shape. I have never seen this problem on an Octalink before.

Medium strength loctite (blue). You'll need to degrease the bolt and bb spindle threads before applying. Hopefully the splines on the cranks haven't gotten misshaped because of coming loose--

Are you sure it's the right BB? I believe V2 cranks will fit V1 BB - badly. When you take the cranks off, pull the BB and see what part number is on it.

hmm... I just had the left arm on my xt octalink fall off yesterday. Probably never torqued the thing down hard enough which led to a self extraction. There was some distressed metal on the ends of the crank splines but otherwise it seemed ok; I popped it back on with my emergency wrench to get myself back to the car and just now set tightened it up again with a torque wrench. It's raining a lot here now so I probably won't ride it again for a few. I'll let you know if it's a goner or not...

I'll check the BB. I'd hope it is the correct match as it is stock parts on a Devinci Phantom.

Turd:
Ha! I just saw your callsign. My iPod's name is Turd Ferguson, 'sa funny name.

Update: Those octalink cranks seem to be a little more durable than I initially anticipated. The left arm that shook itself loose has performed about six hours of off-road riding time with not apparent trouble.

My crank arms(Deore Octalink) worked themselves loose while I was on tour in sweden this summer. Got them retightened twice at bike shops, the third time it happened I went to a car mechanic and tightened the heck out of them myself and they have stayed tight since. No issues after 1000km of riding. Never took them off to inspect, figured I'd just run on hope and replace them if it got too bad.

Yeah, oddly enough, I retorqued my cranks, they came a bit loose after some riding, so I torqued them down again and they just held up to four laps of a 24hr race without coming loose.