Stuck crank arm bolt
Moderator: robbosmans
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- Posts: 77
- Joined: Thu Jun 26, 2014 1:42 pm
Hi, i have just bought a bike second hand, and I want to remove the existing chainset for another..
BUT. The left crankarm (two bolts) has one bolt rounded and I cant get it out.
The chainset is a Shimano 105 /5750..
The bolt is a 5mm allen.
How do I get it out?
I have tried the torx method, the 5.5mm allen and i just bought a set of extractors, but I dont want to risk it. <br/>
Help much need and appreciated!
BUT. The left crankarm (two bolts) has one bolt rounded and I cant get it out.
The chainset is a Shimano 105 /5750..
The bolt is a 5mm allen.
How do I get it out?
I have tried the torx method, the 5.5mm allen and i just bought a set of extractors, but I dont want to risk it. <br/>
Help much need and appreciated!
Last edited by Frankie - B on Mon Mar 26, 2018 2:54 pm, edited 1 time in total.
Reason: Removed the shouting from the topic title and cleaned out the non phpbb coding.
Reason: Removed the shouting from the topic title and cleaned out the non phpbb coding.
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I used a torx bit and hammered it in at least 2mm.
Then I greased up and overtorqued the other bolt, to put less pressure on the bad one.
Then with a 1/4 inch socket wrench and a lot of body weight on it, I managed to get the damaged one out.
If that hadn't worked I would just have drilled the bolt out which is not easy.
Because the bolt head is in a recess it limits your options.
Heat is your friend. Alloy (arm) expands more than steel (bolt) so get everything nice and toasty like 80 degrees and try again as mentioned above.
/a
Then I greased up and overtorqued the other bolt, to put less pressure on the bad one.
Then with a 1/4 inch socket wrench and a lot of body weight on it, I managed to get the damaged one out.
If that hadn't worked I would just have drilled the bolt out which is not easy.
Because the bolt head is in a recess it limits your options.
Heat is your friend. Alloy (arm) expands more than steel (bolt) so get everything nice and toasty like 80 degrees and try again as mentioned above.
/a
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- Posts: 77
- Joined: Thu Jun 26, 2014 1:42 pm
thanks for the answer
witch torx bit size did u you on a 5mm?
Can i heat it with a hairdryer?
I dont own a socket wrench, but will a screwdriver work?
witch torx bit size did u you on a 5mm?
Can i heat it with a hairdryer?
I dont own a socket wrench, but will a screwdriver work?
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- Posts: 77
- Joined: Thu Jun 26, 2014 1:42 pm
Also, did you remove the plastic crank arm bolt before doing it?
there are also extractors that are similr to what @alcatraz mentions that are specific to extracting rounded bolts. most hardware places sell them or on Amazon.
- Factor Ostro VAM Disc
- Factor LS Disc
- Specialized Aethos Disc
- Sturdy Ti Allroad Disc
- Guru Praemio R Disc
- Factor LS Disc
- Specialized Aethos Disc
- Sturdy Ti Allroad Disc
- Guru Praemio R Disc
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- Posts: 77
- Joined: Thu Jun 26, 2014 1:42 pm
I have a extractor but it dosent work by itself.. Should i buy a metal drill first and when try to extract it?
The chainset is barely new, so I would like to remove it and reinstall with new grease..
The chainset is barely new, so I would like to remove it and reinstall with new grease..
the extractors have a reverse knurled and sharp edges which 'grabs' the inside where its rounded (on a hex) and digs in to extract it. no drill required.
- Factor Ostro VAM Disc
- Factor LS Disc
- Specialized Aethos Disc
- Sturdy Ti Allroad Disc
- Guru Praemio R Disc
- Factor LS Disc
- Specialized Aethos Disc
- Sturdy Ti Allroad Disc
- Guru Praemio R Disc
Visit starbike.com Online Retailer for HighEnd cycling components
Great Prices ✓ Broad Selection ✓ Worldwide Delivery ✓
www.starbike.com
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- Posts: 77
- Joined: Thu Jun 26, 2014 1:42 pm
I will take it to the LBS. I tried a blacksmith, but he surgested a screwdriver and a hammer.. Didnt work..