Advice on removing crank
 

Hi,

I need to get into my bottom bracket, but struggling to remove the crank. I borrowed at Park CCP2 but doesn't fit. Can anyone advise me?

Thanks

http://bikeforums.net/attachment.php...hmentid=273143

Hi Monch07, welcoem to the forums. Why doesn't it fit? It won't screw into the threads on the crank? You did unscrew the center part that pushes against the spinddle before trying to screw it into the crank right?

Are the threads in good shape? Is the crank a "standard" brand like shipmano, SR, Suntour, SRAM?

http://www.bikeforums.net/attachment...3&d=1347804566

It is hard to see but there isn't anything still in there like part of a old plastic dust cap or something?

Thanks for the quick reply. The crank is a EU Bicycle Co crank.

The hole's just way too small. Yeah, took the dust cap off, then unscrewed the bolt with a 6mm Allan key.

This is the crank puller I've got, http://bikeforums.net/attachment.php...hmentid=273144and neither the removable part nor the main part will fit in the hole.

which hole? the larger outer threaded section is meant to thread into the crank arm. then the other part pushes against the spindle to pull or rather push the crank off.

search the park tool website and you tube for videos.

The outer section won't thread into the crank arm, it doesn't fit in. And even the other part doesn't fit in the hole in the crank arm.

It's hard to be sure from your picture but there seems to be an outer ring still in the crank arm now that the fixing bolt has been removed. Maybe it's a dust cap. Can you unthread it or pop it out? Its outer diameter seem to be about right for a standard crank puller.

This might be a "one key" system, which doesn't use a crank puller tool, because the removal "tool" is built in. These were popular for a while.

In this design, the bolt is kept in the arm via the "dust cap" ring. When you back off the bolt far enough, it pushes against the ringpushing the crank arm off the spindle. You're top-off is if when you turn the bolt, it loosens and is free for a turn or two, then jams. That's it jamming against the ring, continue turning it to the left and you'll remove the crank. Note that a decent amount of torque is needed. Also before starting, spray some oil into the gap between the bolt and ring, to eliminate the dry friction when the bolt is backed up into it.

Yeah, that was my first thought too and the 6 mm center bolt is what Suguino used for their "Autex" system but the OP says he removed the fixing bolt so I'm not sure how he got it out without pulling the arm.

It's a mystery to me. I don't know of any standard crank bolt that could hold a crank arm on and still fit out through that hole. Remember, that to hold a crank to a Sq. taper spindle, the head of the bolt would have to be at least 12mm across.

Thanks for the comments.

There's nothing else that seems to be able to come off.

Here are a few more photos. https://plus.google.com/photos/10077...21983168429265

I should have said, the Allen key for the bolt was 6mm, but the bolt is 8mm diameter.

Around here you could get a replacement bike of that quality level for $25, maybe that's the way to go?

But if you really wanna...

If the cranks don't have any make/model/parts numbers stamped on them and the (probably self-extracting) bolt system doesn't seem to work then maybe it's time to try getting a gear puller in there.

Ok I think I an deduce what might be happening. You did have a one key system, but when you removed the bolt, the flanges that push against the ring, sheared off (probably because they were rusted through).

At this point the best approach is to jack the arm off from the back. My tool of preference for this job is a set of Jacob's Chuck #6 removal wedges, (cost under $10.00 in the USA) but You can sometimes simply pry it off with a crowbar. If using a crowbar, you have to get the point all the way to the spindle, then rock back against the face of the BB cup.

Yes, I know. All the bolted square taper bottom brackets i've ever seen use an M8x1.0 threaded bolt. The hex head versions are either 14 or 15 mm. Allen type fixing bolts use either an 8 mm, or more rarely, a 6 mm Allen wrench.

There is still a ring in there that needs to come out to result in a threaded hole in the arm that will fit the removal tool.

Yeah, the dust-cap ring that the one-key release crankarm-bolt pushes against is still in the arm.

Easiest way I've found to remove cranks like these is to use some 18" motorcycle tyre-levers. Wedge the straighter end of the levers between crankarm and BB-cup and pry. >POP< comes off in less than 3-5 seconds most of the time. In some rare cases, I have to pry at a spot 180-degrees opposite the first time and by now, 100% of cranks I've tried this on has come off. Ok, so it took 10-seconds total some of the time. But the crank's undamaged and can be re-used as well.