my self extracting bolt is tearing apart the threading .....

[bduc61]

I am trying to undo some old shimano 600 cranks on a old bike
ther are mounted with self extracting bolts

so here am I with my allen key anticlockwise and a tube to have a bit of lever
it moved but after a few seconds, I realized that
the crank is so "glued " to the bottom bracket axis that it is the threading of the crank that is starting to be torn apart :shock: :cry:
and the crank is not getting pulled away :evil:
it is the bolt which is being pushed outside of the crank

what shall I do next ?

I fear that the crank threading is half dead not to say dead already

so If I insist, I am just going to kill it completely ?( unless the self extracting bolt is not very thick so there may stay a bit of it safe in the bottom of the hole ?)

anybody has a next step (not drastic ) at least to undo the crank , even if may not be reused ?

thanks for the tips :idea: ( spraying WD40 was done already but without any result !)

 

[Robbied196]

Re: my self extracting bolt is tearing apart the threading .

You need to remove the cap with a pin spanner, then the bolt. The bolt has a seat on the head which is retained by the cap, it sounds like by undoing the bolt with the cap in place, the bolt is driving the cap out and stripping the threads which is how it is supposed to work but often doesn't! Once the cap and bolt are removed check there is no washer stuck inside, the use a normal crank extractor tool. Hopefully there's enough thread left to get them off

I don't rate these self extractors they always seem to give problems.

 

[bduc61]

Re: my self extracting bolt is tearing apart the threading .

You need to remove the cap with a pin spanner, then the bolt. The bolt has a seat on the head which is retained by the cap, it sounds like by undoing the bolt with the cap in place, the bolt is driving the cap out and stripping the threads. Once the cap and bolt are removed check there is no washer stuck inside, the use a normal crank extractor tool. Hopefully there's enough thread left to get them off

I don't rate these self extractors they always seem to give problems.

the cap needs to be undone clockwise right ?

 

[jonnyboy666]

Re: my self extracting bolt is tearing apart the threading .

2nd that, have seen it before, the cap that the bolt is pushing against is weaker than the crank arm stuck on the axle. it will either break the cap or ruin the thread in the crank arm or axle or worst case both.

remove it all and check the crank arm thread then use a normal extractor, screw the first part into the crank arm as deep as possible before winding in the 2nd part of the extractor.

hopefully that should work, if the thread is dead then find an old school shop that has something called (i think) a steiner tool, it looks light a normal crank extractor but cuts its own thread into the crank arm, it does however mean that you would only ever beable to use that tool to remove the arm at a later date but it does usually save both the arm and the axle.

and, no, the cap undoes anticlockwise

 

[Robbied196]

Re: my self extracting bolt is tearing apart the threading .

the cap undoes anticlockwise

And then throw them in the bin

 

[DA-EVO]

Re: my self extracting bolt is tearing apart the threading .

I think, if you have problems, I have a spare Shimano 600 drive side crank in that style.

Let me know if its of use, its probably 170mm

Its yours for the postage.

(The left hand arm on mine failed at the taper many years ago).

 

[Ian Raleigh]

Re: my self extracting bolt is tearing apart the threading .

Hope the crank comes off after that! Nothing worse and has happened to me too but I fully ripped out my self extractor :cry:

Don't get smashing the fook out of the crank if the normal extractor doesn't work, It'll only cost you more in the long run.

 

[bduc61]

Re: my self extracting bolt is tearing apart the threading .

You need to remove the cap with a pin spanner, then the bolt. The bolt has a seat on the head which is retained by the cap, it sounds like by undoing the bolt with the cap in place, the bolt is driving the cap out and stripping the threads which is how it is supposed to work but often doesn't! Once the cap and bolt are removed check there is no washer stuck inside, the use a normal crank extractor tool. Hopefully there's enough thread left to get them off

I don't rate these self extractors they always seem to give problems.

ok i have got several pin spanners but the bloody pins have a greater diameter than the holes of the cap which are really small !

it not the first time that it happens

and as the cap has torn some threading it is not free anymore to turn easily, and I can put some pliers with very thin tips in them but can't turn with enough force :evil:

will look at the park tool ones and try to check before buying that they have small enough pins :roll:

I think, if you have problems, I have a spare Shimano 600 drive side crank in that style.

Let me know if its of use, its probably 170mm

Its yours for the postage.

(The left hand arm on mine failed at the taper many years ago).

many thanks
I think I ll take your offer immediately

as I pretty sure the threading is dead enough for reuse :idea: :?

the cap undoes anticlockwise

And then throw them in the bin

sure thing I will do that

 

[bduc61]

Re: my self extracting bolt is tearing apart the threading .

Hope the crank comes off after that! Nothing worse and has happened to me too but I fully ripped out my self extractor :cry:

Don't get smashing the fook out of the crank if the normal extractor doesn't work, It'll only cost you more in the long run.

on another bike, same issue of freezed crank, but i had a crank extractor - same result - it exploded under the load :shock:

how come are we still playing with these old bikes that have spent ages outside and we spend ages to try to rejuvenate them

 

[DA-EVO]

Re: my self extracting bolt is tearing apart the threading .

I think, if you have problems, I have a spare Shimano 600 drive side crank in that style.

Let me know if its of use, its probably 170mm

Its yours for the postage.

(The left hand arm on mine failed at the taper many years ago).

many thanks
I think I ll take your offer immediately

as I pretty sure the threading is dead enough for reuse :idea: :?

I will look for it this weekend and let you know that I still have it, but pretty sure I do.