aener Posted September 16, 2009 Report Share Posted September 16, 2009 Trying to get it off the bottom bracket. Put the extractor in (yes - squarely ) and it was real tight. put a 4' bar over it, and it started moving. Stuck so damned tight it just ripped all the threads out.Tried hammering.Tried crank in the vice, and whack BB with bar+hammer.Trying to avoid heating it if atall possible.Only way I can think of is to cut the BB, and drill/scrape the rest of it out the tapers - though if I can't get it off - I'm not really sure I want to be putting it back on anything.Are stripped threads covered on the warranty, does anyone know?Cheers. Quote Link to comment Share on other sites More sharing options...
forteh Posted September 16, 2009 Report Share Posted September 16, 2009 Trying to get it off the bottom bracket. Put the extractor in (yes - squarely ) and it was real tight. put a 4' bar over it, and it started moving. Stuck so damned tight it just ripped all the threads out.Tried hammering.Tried crank in the vice, and whack BB with bar+hammer.Trying to avoid heating it if atall possible.Only way I can think of is to cut the BB, and drill/scrape the rest of it out the tapers - though if I can't get it off - I'm not really sure I want to be putting it back on anything.Are stripped threads covered on the warranty, does anyone know?Cheers.Can you afford to bin the BB?Heating will be fine although youre best cutting the axle and bunging the whole arm/cut axle into the oven till its about 80*C, then mount the arm in a vice and knock the taper out To check the temperature spit on it, if it balls up and runs off then its about right, if it just sits there then it needs more time in the oven. Quote Link to comment Share on other sites More sharing options...
Muel Posted September 16, 2009 Report Share Posted September 16, 2009 See here:http://www.trials-forum.co.uk/wiki/Removin...stripped_threadWorks everytime, although you may need to put a big jubilee clip round it to stop the legs popping off the crank arm. Only works on crank arms with a definate lip though, so may well not work on the middleburn. Quote Link to comment Share on other sites More sharing options...
bollo you ball-bag Posted September 16, 2009 Report Share Posted September 16, 2009 pour a freshly boile kettle full of water over it then hammer. works every time when my old burns got stuck on Quote Link to comment Share on other sites More sharing options...
durkie Posted September 16, 2009 Report Share Posted September 16, 2009 Can you afford to bin the BB?Heating will be fine although youre best cutting the axle and bunging the whole arm/cut axle into the oven till its about 80*C, then mount the arm in a vice and knock the taper out To check the temperature spit on it, if it balls up and runs off then its about right, if it just sits there then it needs more time in the oven.you've tried this? I'm very very surprised that it works.....aluminum expands with temperature close to double what steel does. even if that weren't the case, everything expands with heat in some fashion...seems to me that you'd want to cool it. Quote Link to comment Share on other sites More sharing options...
Muel Posted September 16, 2009 Report Share Posted September 16, 2009 No, if you heat it like mad, the crank arm will expand more than the BB, so the whole crank arm will end up bigger than before, and will come off the bb more easily. Quote Link to comment Share on other sites More sharing options...
forteh Posted September 16, 2009 Report Share Posted September 16, 2009 you've tried this? I'm very very surprised that it works.....aluminum expands with temperature close to double what steel does. even if that weren't the case, everything expands with heat in some fashion...seems to me that you'd want to cool it.Not with a BB no, but the number of engine bearings Ive taken out of aluminium crankcases over the last 20 years sort of indicates that the technique works You cant really heat one component and cool another when disassembling, when putting together you can though, I usually put bearings int eh freezer for a couple of days before coming to fit them to a heated crankcase, that way they drop in by hand and dont need to be driven in. Quote Link to comment Share on other sites More sharing options...
durkie Posted September 18, 2009 Report Share Posted September 18, 2009 No, if you heat it like mad, the crank arm will expand more than the BB, so the whole crank arm will end up bigger than before, and will come off the bb more easily.well to me, expand like mad means that the bb taper/isis spline hole gets smaller with heat cause the aluminum swells in all directions. but if it works, it works.... Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.