Mountain Biking - Chain ring bolt issues

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kg4kpg
01-20-09, 11:23 AM
Got some frozen and can't get them out. I've used several penetrating sprays but they still won't budge and the holes are just about to thew point where my hex key won't bite. I've got some new bolts to replace these with. This is an older Specialized crank set I'm giving new life to.
TIA

Chris

sirtigersalot
01-21-09, 11:11 AM
try heating and getting the back side of the bolts with a big flathead screwdriver (since the inside is almost stripped) if you can put alot of pressure toward the screw with the screwdriver and use a wrench to turn it. If you have trouble and you have the tools pull the crankarm off
sscyco
01-21-09, 12:41 PM
If the heat does not work take a drill to it - just slightly larger than the hex key hole

frankenmike
01-21-09, 03:36 PM
Two methods I've used: 1.) grind some flats into the side of the nut, grip with a vise; 2.) completely grind off the lip of the nut. Both require removing the cranks and a dremel with a grinding or cutoff wheel. BTW lube the new bolts liberally before installing to prevent a huge PITA in the future.
sirtigersalot
01-21-09, 07:55 PM
If the heat does not work take a drill to it - just slightly larger than the hex key hole

what u really want is a left hand drill or a screw remover, that way it actually spins the unscrew direction and can lock into the metal and just unscrew it, destroys the bolts but meh u've got more
kg4kpg
01-21-09, 08:11 PM
Thanks guys, good info. I do have new bolt so they will gladely sacrifice their lives for the cause. Arms are off so I'll give all ideas a try.
ed
01-21-09, 09:45 PM
They got those "broken bolt/screw extractor thingys now'a'days that work well.
http://moodle.student.cnwl.ac.uk/moodledata_shared/CDX%20eTextbook/dswmedia/images/useScrewextract.jpghttp://www.asseenontvguys.com/productimages/grabit_demo.gif
mcoomer
01-21-09, 10:17 PM
Yeah, use a drill motor with an easy out extractor or simply drill out the bolts. If you drill the bolts out be sure to use a drill that's slightly undersized so you don't damage the chainrings or the spider.

Mike