Crank puller tool has threaded the inside of the crank
#1
Newbie
Thread Starter
Join Date: Nov 2006
Posts: 3
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Crank puller tool has threaded the inside of the crank
Completly taking apart my mongoose front and rear suspension mountain bike I came accross no real problems except getting the chain wheel crank off on my two-peiece crank set.
I got the opposing side's lock-nut and everything else out fine but upon screwing the crank-pulling tool into the inside of the crank and then turning the bolt inwards resulting in griping onto the thread and de-attatching it from the axle it gripped onto the thread -and pulled it out.
Lots of metal shavings later I can't even screw the tool into the crank now, there's that little thread.
Now without having to buy specialised tools or whatever else what's the best way to get the crank off? Any help greatly appreciated.
I got the opposing side's lock-nut and everything else out fine but upon screwing the crank-pulling tool into the inside of the crank and then turning the bolt inwards resulting in griping onto the thread and de-attatching it from the axle it gripped onto the thread -and pulled it out.
Lots of metal shavings later I can't even screw the tool into the crank now, there's that little thread.
Now without having to buy specialised tools or whatever else what's the best way to get the crank off? Any help greatly appreciated.
#2
Boomer
Join Date: Nov 2003
Posts: 7,214
Bikes: Diamondback Clarity II frame homebuilt.
Mentioned: 106 Post(s)
Tagged: 0 Thread(s)
Quoted: 16098 Post(s)
Liked 1,457 Times
in
1,064 Posts
Was this a hollow pipe bottom bracket? Is it possible that there was a crank bolt washer left in the bottom of the hole. This will result in the crank puller both pushing on and pulling on the crank, thus stripped out threads. If the threads are already stripped, then you might as well just pound the crank off with a hammer and replace it with a new one. Be patient and work at it slowly, you do not want to strip out the bottom bracket shell as well.
#3
Senior Member
Take it to a bike shop and pay them to remove the crank. No tools needed!
There are (rare) specialised tools to rethread the crank and a ball joint remover or a bearing puller will probably let you remove the crank. Search the archive for details.
There are (rare) specialised tools to rethread the crank and a ball joint remover or a bearing puller will probably let you remove the crank. Search the archive for details.
#4
Boomer
Join Date: Nov 2003
Posts: 7,214
Bikes: Diamondback Clarity II frame homebuilt.
Mentioned: 106 Post(s)
Tagged: 0 Thread(s)
Quoted: 16098 Post(s)
Liked 1,457 Times
in
1,064 Posts
Once the crank is rethreaded, will a new larger crank extractor be required. As I read this post it appears that the threads have been pulled out the front of the crank and the hole is now too large to rethread at the current size? Sounds like the new threaded hole will have to be larger.
#6
Senior Member
Join Date: Aug 2004
Posts: 736
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Originally Posted by The Great Stonk
if its a 2 piece external BB unit you dont use a crank puller to remove the cranks. unless you have cranks im not familiar with.
The suggestion of re-boring + threading the crank-arm assumes that the cost of this operation plus a new, custom crank puller to service this now-unique crank-arm is cheaper than a new crank-arm.
2 reasonable options:
1. Put the now problematic crankarm back in place, and assume that your ability to service the BB will be quite limited from now on (which may be ok for a while), or
2. Replace the crank arm.
You can do #1 for a long while, and then later #2.
#7
Senior Member
Sometimes this happens if you don't screw the puller far enough into the arm. This happened to me the first time I removed a crank arm- the screw that torques the arm off in the end was keeping me from screwing the puller far enough in, and when I went to pull it, out came the threading. Really stinks.
#8
Elitist Troglodyte
Join Date: Jun 2006
Location: Dallas
Posts: 6,925
Bikes: 03 Raleigh Professional (steel)
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Likes: 0
Liked 1 Time
in
1 Post
They can helicoil the threads which brings them back to the same size, so you'd use the same puller.
__________________
Stupidity got us into this mess - why can't it get us out?
- Will Rogers
Stupidity got us into this mess - why can't it get us out?
- Will Rogers
#9
Newbie
Thread Starter
Join Date: Nov 2006
Posts: 3
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Thanks for your help. As I wasn't sure of the mechanics I'm a little more clea on what I'm trying to do now.
Hah, thankfully I'm not alone.
Well basically I've already had to replace the other crank and due to other advice tried to "bash" this crank off using a mallet, hitting against the chainwheel (yes this crank is now totally ruined and I'm willing to replace).
To those who asked, yes the end of the axle is square to which the crank is pushed onto, really hard. I have tried levering it and have hit the chainwheel so hard it's bent out on not far from a 45 degree angle.
Should this require this much force? It's kind of frustrating to be pounding the absoloute **** out of this and not be getting anywhere. I'm not just smacking the chainwheel either, the way I'm hitting it I'm still applying a huge ammount of out-ward force.
So what's the best advice when you have no regard for the condition of the crank? Is persistance the key, because I'm not sure if I've even moved it, I'm just trying to get a benchmark for how much force this is actually going to take.
Originally Posted by matimeo
Sometimes this happens if you don't screw the puller far enough into the arm. This happened to me the first time I removed a crank arm- the screw that torques the arm off in the end was keeping me from screwing the puller far enough in, and when I went to pull it, out came the threading. Really stinks.
Well basically I've already had to replace the other crank and due to other advice tried to "bash" this crank off using a mallet, hitting against the chainwheel (yes this crank is now totally ruined and I'm willing to replace).
To those who asked, yes the end of the axle is square to which the crank is pushed onto, really hard. I have tried levering it and have hit the chainwheel so hard it's bent out on not far from a 45 degree angle.
Should this require this much force? It's kind of frustrating to be pounding the absoloute **** out of this and not be getting anywhere. I'm not just smacking the chainwheel either, the way I'm hitting it I'm still applying a huge ammount of out-ward force.
So what's the best advice when you have no regard for the condition of the crank? Is persistance the key, because I'm not sure if I've even moved it, I'm just trying to get a benchmark for how much force this is actually going to take.
#10
Elitist Troglodyte
Join Date: Jun 2006
Location: Dallas
Posts: 6,925
Bikes: 03 Raleigh Professional (steel)
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Likes: 0
Liked 1 Time
in
1 Post
When you hit it you rotate it against the taper and jam it. You may be able to drive it out eventually by hitting it alternately on opposite sides, making it rock on the taper.
But the best way to do it is to use an automotive gear puller.
But the best way to do it is to use an automotive gear puller.
__________________
Stupidity got us into this mess - why can't it get us out?
- Will Rogers
Stupidity got us into this mess - why can't it get us out?
- Will Rogers
#11
Senior Member
Ouch, you've ruined the crank then?
Try this. Find a socket that just fits completely inside the square of the crank arm. Stand the socket on a concrete floor. Position the bike over the socket so the socket is inside the square of the crank arm. Have someone hold the bike in that position.
Use a long flat end punch and a 2.5 lb hammer to hammer the crank off. Be sure to hit the crank arm as close to the axle as you can. If you are worried about cosmetics, put a very large flat washer between the punch and the crank arm to prevent marring.
Try this. Find a socket that just fits completely inside the square of the crank arm. Stand the socket on a concrete floor. Position the bike over the socket so the socket is inside the square of the crank arm. Have someone hold the bike in that position.
Use a long flat end punch and a 2.5 lb hammer to hammer the crank off. Be sure to hit the crank arm as close to the axle as you can. If you are worried about cosmetics, put a very large flat washer between the punch and the crank arm to prevent marring.
__________________
Il faut de l'audace, encore de l'audace, toujours de l'audace
1980 3Rensho-- 1975 Raleigh Sprite 3spd
1990s Raleigh M20 MTB--2007 Windsor Hour (track)
1988 Ducati 750 F1
Il faut de l'audace, encore de l'audace, toujours de l'audace
1980 3Rensho-- 1975 Raleigh Sprite 3spd
1990s Raleigh M20 MTB--2007 Windsor Hour (track)
1988 Ducati 750 F1
#12
got to ride
Join Date: Nov 2006
Location: California
Posts: 8
Bikes: Trek 950, Raleigh Columbia, Motobecane,
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
socket, punch and hammer sound like it would work. I had a fit one time when the threads were worn on one of my crank arms. here is what worked for me. clean both the crank threads and puller threads super good with a solvent like denatured alcohol. apply some epoxy to the threads and turn in the puller body. let it set a few hours. 24 is best. proceed as normal with the removal. gently heat the crank arm with a propane torch, the glue will soften and the puller with turn right out. Gentle is the word of the day. Unlike steel, aluminum doesn't get red hot as a warning before it melts. You shouldn't be getting it anywhere near that hot though. you should be able to hold the crank in your hand with a potholder and get the job done.
#13
Senior Member
Join Date: Jan 2005
Location: Kansas City
Posts: 658
Bikes: Diamondback centurion. Home built tandem
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 6 Times
in
2 Posts
Originally Posted by San Rensho
Ouch, you've ruined the crank then?
Try this. Find a socket that just fits completely inside the square of the crank arm. Stand the socket on a concrete floor. Position the bike over the socket so the socket is inside the square of the crank arm. Have someone hold the bike in that position.
Use a long flat end punch and a 2.5 lb hammer to hammer the crank off. Be sure to hit the crank arm as close to the axle as you can. If you are worried about cosmetics, put a very large flat washer between the punch and the crank arm to prevent marring.
Try this. Find a socket that just fits completely inside the square of the crank arm. Stand the socket on a concrete floor. Position the bike over the socket so the socket is inside the square of the crank arm. Have someone hold the bike in that position.
Use a long flat end punch and a 2.5 lb hammer to hammer the crank off. Be sure to hit the crank arm as close to the axle as you can. If you are worried about cosmetics, put a very large flat washer between the punch and the crank arm to prevent marring.
Back in the day we used to remove the bolt, and hit the crankarm with a hammer to get her it off. Put a towel or something over the crank arm to protect from cosmetic damage.