How to: Repair stripped puller threads on cranks

[Nabeaquam]

I just pack out the gap between the back side of the crank thats stripped and bottom bracket/shell (open ended spanner/s etc) and then pull the bottom bracket from the okay side by first removiong the cup and then pulling the axle by way of large socket/washers slipped over the BB axle and butted upto the BB shell and a long crank bolt (M8 I believe). This works every time for me thus far... essentially you pull the BB axle instead of pulling the crank arm. Takes about 10 mins.

Excellent idea. I’ll use it. But, if both sides are stripped like mine was from the bike shop using the wrong puller then your only recourse is a pickle fork and sometimes added leverage by using pry bars along with the pickle fork. This method gouges up the inside of the alloy crank arms.

 

[bagpuss]

Wonderful idea .I have a pair of Williams AB 77 cotterless cranks with worn out thread on one side.
These been the only period British made c/s. Splined as well ,they are worth saving

 

[bikeworkshop]

The pickle fork works a lot better if you get the crank arm hot. Often you can then lever it off without leaving a mark.
My worry with the jb weld is that it will be no stronger than the alloy threads, which weren't up to the job of pulling the crank off.
Of course if it's torqued right and regreased once a year, it might be fine
- and if you ever feel you're overdoing the force on a tapered crank extractor, a little heat could be your friend and might save the threads in the 1st place.

 

[dinozoiks]

That all sounds sage advice. To be honest, it’s a garage queen now as I retired the poor thing years ago. It definitely earned it. Bought it new in ‘91 and raced / commuted on it for a good 15 years. It’ll probably get the heat and pickle fork treatment next time anyway. So thanks for the tip.

 

[danson67]

For anyone who can't get easily their hands on JB Metallic Epoxy, there's a similar product from Henkel/Loctite that does the same job, PC-3967:

https://next.henkel-adhesives.com/u...cher.html/loctite-pc-3967/BP000000164704.html

And if the thread is completely stripped out, there is a VAR crank thread repair system (PE-11000). This reams out and replaces the damaged thread with a new, larger diameter one. I have this, if anyone needs the job doing.
https://www.vartools.uk/m24x15-repair-kit-for-extractor-thread-in-crank-c2x36007258

All the best,

 

[Woz]

You are all amateurs with your mumbo jumbo glues and special tools. Unfit and forget is my approach.

 

[dinozoiks]

For anyone who can't get easily their hands on JB Metallic Epoxy, there's a similar product from Henkel/Loctite that does the same job, PC-3967:

https://next.henkel-adhesives.com/u...cher.html/loctite-pc-3967/BP000000164704.html

And if the thread is completely stripped out, there is a VAR crank thread repair system (PE-11000). This reams out and replaces the damaged thread with a new, larger diameter one. I have this, if anyone needs the job doing.
https://www.vartools.uk/m24x15-repair-kit-for-extractor-thread-in-crank-c2x36007258
View attachment 828517
All the best,

That VAR tool makes so much sense. But £153 plus £34 postage? Yikes. Glue and bodge it is then…

 

[Ren Rawbor]

You are all amateurs with your mumbo jumbo glues and special tools. Unfit and forget is my approach.

View attachment 828757

This is my preferred option for anything Octalink, stripped thread or not...

 

[Nabeaquam]

The weather guesser musta been stoned, we only got a few cm of slush and the winds have dropped to almost 0. It’s still snowing the wet stuff but the winds only reached 60 km gusts last night. We’ll see hew much we get overnight but it looks like a lotta hype. We sure aren’t getting the predicted 90cm with 100 km/hr winds.

 

[dyna-ti]

Snow is good. great for doing snow angels. But impromptu ones like this are not the way to do it.


To avoid the puller tearing out you really need to make sure its tight when you start to do up the puller bit. Not just hand tight, it needs to be tight as tight can be(obviously without tearing the threads from overtightening) So as tight as you would tighten a pedal.

I'd a nice set of Cooks Bros cranks in purple. And i didnt tighten the puller properly, so that when i started to turn the center bit i felt it begin to tear out. Bloody Blind Panic ensued Stopped, and didnt try to undo it, but took the whole bike down to the bike mechanics who worked his magic on them.
Lesson learned. Tighter than hand tight.