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HELP! = stripped crankarm
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don
Jan 21, 04 16:40
Post #1 of 13 (2836 views)
SO I've lurked and lurked and lurked. I haven't posted ( I don't think)since the forum was still in the old format; buuut now I'm stuck. I was taking apart my bike this evening (to get a snazzy new paint job) and apparently stripped out the crank arm (non-drive side, Ironlight, not the cool new compact ones, square-taper BB). I've done it a million times (maybe not that many, but a bunch) and never had a problem. I screwed in the big extractor bolt and then when I screwed in the little one with the handle on it, the whole thing popped out in my hand including a bunch of little metal fragments, thus the "stripped" diagnosis.



SO, Oh bike genius gurus who rule this land, please help me. what can I do, if anything, at this point? Hacksaw off the spindle (and I was seconds from that tonight before coming to the computer). For what it's worth I'm in North Central Vermont with a truckload of MTB shops and little to no road/tri shops (outside of Ian's little shop in Waitsfield). I've even thought of supergluing the big bolt inside the crankarm and sacrificing the tool/crankarm, just to get the damn thing off. Any and all suggestions at this point are game because tomorrow out comes the the hacksaw.

Many, many thanks ahead of time.
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Re: HELP! = stripped crankarm [don] [ In reply to ]
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cerveloguy
Jan 21, 04 17:04
Post #2 of 13 (2831 views)
You might want to repost this on the newsgroup rec.bicycles.tech.

Haven't had this happen but I remember when playing with old cars if I stripped something you could get a tap tool and make new threads the next bolt size up. I'd assume a good bike mechanic should be able to fix this for you.
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Re: HELP! = stripped crankarm [cerveloguy] [ In reply to ]
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toolguy
Jan 21, 04 18:53
Post #3 of 13 (2818 views)
Retapping to a larger size will not help,you will not have a puller to fit the new thread size,right of left side crank? the crank is toast so instead of cutting the spindle,that could be hard to saw,i would saw the crank,the left side would be easyer to do, but both could be done,you could also try prying it off with the correct pry bars and being very careful not to hurt the bottom bracket.If you try to saw it off i would start on the outside sawing toward the bottom bracket and try to parallel the flat on the taper on the bottom bracket,if done right the taper on the spindle will even guide the saw blade,If this sounds to hard go to your auto store that rents pullers and get a bearing plate to go behind the crank then attach a puller to it and pull it off,some times a three leged puller will work.Did you forget to remove the washer???? Hope this helps
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Re: HELP! = stripped crankarm [don] [ In reply to ]
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justaoldroadie
Jan 22, 04 4:12
Post #4 of 13 (2801 views)
try a wheel puller, have heard this works, never did it though. Works like the extractor but it has claws that grab the outside of the crank arm. Have also heard of people using pry bar between the bb and crank arm, don't think I would try this as the possiblity of damage to the bb.

The bike shops might have the wheel puller.

Good luck,
Bob
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Re: HELP! = stripped crankarm [don] [ In reply to ]
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t-t-n
Jan 22, 04 6:04
Post #5 of 13 (2779 views)
this is just one of those lessons you pay for - the best kind. best to just cut your losses. go get some fresh hacksaw blades, make some coffee, put on a killa CD, and cut that mofo off'n there. that puller business might work and it might not. might mung up the frame and might not, any which way it will take time and cost more than you already have spent. just suck it up and get it done. hey, you needed a new spindle and crank anyway, eh?
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Re: HELP! = stripped crankarm [don] [ In reply to ]
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bunnyman
Jan 22, 04 6:20
Post #6 of 13 (2775 views)
I would just saw that mofo off. The crank arm's done. I would try a Demel with a composite disc (the type that is the firmer, harder material, not the thin discs) and try to align the disc with the square of the BB spindle. I wouldn't try to use the puller only from fear that you could muck things up. If you don't get it quite down to the spindle, never fear-that's what the grinder from your Dremel is for. As long as you get one side of the square hole off, you're good to go.
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Re: HELP! = stripped crankarm [bunnyman] [ In reply to ]
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Record10Carbon
Jan 22, 04 6:25
Post #7 of 13 (2771 views)
Things to try



1 - JB Weld a large nut to the crank arm, put a bolt through the nut to get the arm off. (crank still ruined)

2 - tap out with larger threads, install a crank arm extractor with Lock Tight RC680 on the threads (maybe able to be used more than once).

3 - Hack saw? Screw that, get a Dremel as someone said.

4 - Steering wheel puller from a car (can be used over and over again)

5 - Ride the bike on a trainer...trust me, the crank will come off after a bit and it WONT do it so suddenly that you get hurt.

6 - Buy crank arm extractors that are perminant...no issues after that.
----------------------------------------------------------

What if the Hokey Pokey is what it is all about?
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Re: HELP! = stripped crankarm [don] [ In reply to ]
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Frank Day
Jan 22, 04 6:30
Post #8 of 13 (2769 views)
You could just leave the spindle bolt off, put the bike on the trainer and strart riding. Eventually, the crank would work itself loose. I did this inadvertently once ("borrowed" a crank bolt from my bike and forgot to put it back). It took several weeks for the crank to work off, although that was on a Shimano octalink BB.

Frank
--------------
Frank,
An original Ironman and the Inventor of PowerCranks
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Re: HELP! = stripped crankarm [Record10ti] [ In reply to ]
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bunnyman
Jan 22, 04 6:32
Post #9 of 13 (2768 views)
6 - Buy crank arm extractors that are perminant...no issues after that.

That is no joke. Threads in aluminium are not meant to be used over and over again. The material is very soft. Which is why I leave anything that is aluminium alone (well, grease up anything going into aluminium threads with LOTS of grease) for the most part.

I believe that threads should be helicoiled when it comes to anything aluminium, but getting manufacturers to do that is an entirely different story...
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Re: HELP! = stripped crankarm [bunnyman] [ In reply to ]
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don
Jan 23, 04 5:25
Post #10 of 13 (2729 views)
thanks a ton you guys...this forum rules (and so do Dremel/Roto-Zip tools)
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Re: HELP! = stripped crankarm [Record10ti] [ In reply to ]
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toolguy
Jan 23, 04 6:47
Post #11 of 13 (2710 views)
The time you just screwed away trying to JB weld or Dremeling it off i would already have hacksawed it off. Lock tite works by being but into a small aera where air can not get to it,then it hardens,putting in a larger thead then trying to use locktite is a flat waste of time
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Re: HELP! = stripped crankarm [randall t] [ In reply to ]
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Record10Carbon
Jan 23, 04 7:27
Post #12 of 13 (2702 views)
In Reply To:
The time you just screwed away trying to JB weld or Dremeling it off i would already have hacksawed it off. Lock tite works by being but into a small aera where air can not get to it,then it hardens,putting in a larger thead then trying to use locktite is a flat waste of time
That will depend on your frame, BB and your skills. I would much rather wait for JB weld to harden than hit my OCLV frame with a Dremel bit in a hurry. Maybe this is on a Klein where the BB shell is right on the crank arm? There are allot of frames and situations where diffrent things should be done. I have USED LockTite for this very issue in the past and it works quite well....note, when I suggested LockTite - it was RC609, not the blue 242 that is common in cycling. RC609 will fill larger gaps and requres heating of parts for removal...it is tough stuff. Putting on a larger thread, a helicoil and an extractor sure costs allot less than a new crank arm in some cases.
----------------------------------------------------------

What if the Hokey Pokey is what it is all about?
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Re: HELP! = stripped crankarm [don] [ In reply to ]
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SuperDave
Jan 24, 04 18:01
Post #13 of 13 (2663 views)
VAR makes a tool for this application. It slides over the crank arm, from the bottom once the pedal is removed. There is a small "c-clamp" that holds it in place, then there is a tradtional plunger that pushes on the BB spindle just like your Park too does.

A ball joint remover will work also. This is basically a two pronged fork that has tapered tines, tapping the fork on either side of the BB spindle will force the arm off by pushing on it and the BB cup.

If you can get the BB out, you'll be way ahead too. No sense keeping the frame in your way.

If you can take off at least one crank arm, you can just remove the BB and the threads from the BB and the frame will force the crank arm off the spindle as you try to remove it from the frame.

The thermal expansion of Aluminum is much greater than that of the steel BB spindle so getting the thing hot is your friend. No hotter than boiling water. Though as you'll want to avoid temps over 400 degrees F and anything hotter than 212 makes it tough to handle.

I think I've fixed this problem 40 or 50 times in my days as a shop mechanic. Don't resort to a hack saw, you needn't give up the part.

Good Luck,
SuperDave
https://www.kickstarter.com/...bike-for-the-new-era
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