nut size
- Thread starter billyboya
- Start date
They put so much paint on threads sometimes. Easy to mess up if you don't screw it in perfectly straight - best to turn gently anti-clockwise first, until you're certain. If you've got some acetone, soak a bit of cloth, wipe the thread and dissolve the paint... then if you oil the tool and retract the bolt first as much as possible, you may be able to screw it in far enough? Looks like there's lots of internal thread left. On the other hand, you may make matters worse and have to take it to the bike shop anyway.
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Bingo Ive sorted it. it wasnt the BB after all. I just assumed it was silly me. but it was the left pedal arm which seemed to keep getting loose. I tried it again really banged it hard onto the BB spindle, and got these special bolts which arrived today just in time too the pedal arm now is really tight, I think what happened was I didnt put the original bolt back into the BB spindle. as I can remember now not being able to find original bolt, so used what I had at the time, but obviously that had worked loose. sorry all to have mislead you about BB. But least I have the tools if required another time. But as for the chain side, well i would probably have to check whats best on that when the time comes.
just like to thank everyone here, who has helped and suggested things, its most appreciated
regards billyboy
just like to thank everyone here, who has helped and suggested things, its most appreciated
regards billyboy
If you can't screw it in 3 turns (minimum) by hand don't put a spanner on it was the mantra I was taught as an apprentice in the last century. Still holds true for anything mechanical made now.
Whatever side you're wanting to unscrew, you don't unscrew in the same direction you pedal the bike forwards. Pedalling forwards doesn't unscrew what you're trying to unscrew, or it'd unscrew whenever you pedalled forwards.
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Can you show us a picture of the end of the crank extrator - the bit that pushes against the shaft. It looks like you might have the wrong one.
Judging by the witness marks on the crank you are probably correct. Some crank extractors require leaving the bolt in but loose to enable you to apply pressure in the correct place (don't know if that is still the case but was certainly the way mine was in the mid 70's when I bought my first ' cotterless chainset')
I'm kicking myself for never thinking of that. Different tools have different sized pieces that go through to thye crank. Those for Octalink and Bosch motors need to be just the right size. I've had circumstances before, where the crank wouldn't come off. it was absolutely solid with a different feel to normal, then I found out that the big inner piece wasn't pressing on the shaft. It was up against the square hole in the crank.
Look at the weird marks on the side of the square in post #38, though that might have been caused because the tool was cross-threaded.
Excellent, glad you've sorted it.
It seems my accidental off-topic posts weren't off-topic after all!
Saneagle above is concerned that perhaps your tools 'pushing end' is sized and shaped such that it pushes into and not onto the axle end. if so perhaps blutack and a small coin could provide a surface to push against?
Do you mean the end part of that silver piece what has to push against bb spindle
Well I have sorted out the problem about my left pedal arm was too loose but now I have banged it on harder to bb spindle plus used special bolts it’s much better now as before it kept slipping.
Regards to the above what saneagle said I think he means the size of the end part of that silver bit which is suppose to push against bb spindle
I don’t need to remove bb now but this info will help in case I need to do it one day
Yes. If it's too big, it presses on the top of the square of the pedal arm/cranc instead of the spindle.
Well it seems I have spoke too soon about pedal arm is sorted, as today i went out on bike and felt the left pedal arm loose again, obviously by pedalling has unscrewed the bolt which hold pedal arm. I was wondering if to use thread lock liquid. but then if at a later date i need to change the BB how will the nut unscrew after been coated with thread lock glue.
So it seems I either need to really tighten that nut much more. or is it the thread in BB
saneagle here is a picture of that part you asked about
Attachments
Unfortunately the likelihood is the crank arm is damaged if it has been loose for any length of time. If it isn't damaged then torquing it up properly should do it. Clean and degrease the arm and the spindle then tighten it to 40Nm, ride the bike for about 30 miles then re torque. Do it again after another 30 miles, if you find there is any further movement then the arm is damaged
Well Im afraid I dont have a torque wrench, so I guess I will just have to try and tighten it up a bit harder. would it be the BB spindle thread damaged then. as the bolt does go all way in and was very tight
If you can tighten it 'very tight' there is nothing wrong with the threads. The problem is usually that the taper on the (usually) aluminium crank arm gets distorted when there is any movement. This means the tapers aren't the same so won't lock.
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