Daboo

I've partially stripped the nuts on two(!) Park tool crank pullers trying to get a stubborn crank arm off. The left one came off with more effort than I think should be necessary. All the guides I read said that the arm should pretty much fall off without much effort. The crankset is a Sugino XD 600 (I'm pretty sure - stock on a 2008 surly LHT). There is no washer inside. I threaded the nut in by hand until it stopped (separated from the inner bolt completely). I screwed in the inner piece, tightened it as far as it would go and the arm wouldn't budge. Any suggestions? I'm going to give WD-40 a shot as mentioned in another thread. Can I use a partially stripped nut to still try and get it off or do I need to start with a fresh one?

HillRider

You stripped the hardened steel threads on the crank puller but didn't damage the threads inside the aluminum crank arm????

rhenning

Take the washers out of the holes after you remove the bolts on the spindle. Roger

dperreno

Well, he said there were no washers, and the picture confirms that. I would ask if you are using the right tool? Park makes two versions of their crank pullers: one for square taper cranks and one for octalink and ISIS cranks. They are not interchangeable. Is the center section of your tool narrow enough to fit through the square hole in the crank and contact the spindle? If not, then you are just pushing against the crank instead of the spindle.

cbchess

if you go ride your bike around the street for a few minutes the crank will fall off

JohnDThompson 

That doesn't look like you've stripped the threads on the puller; rather it's shards of aluminum from the threads in the crank arm. I'll bet if you took a small nail or other pointy object you could clean them out of the puller threads and see that they're not damaged.

The bad news is that your crank's threads are being destroyed. Once you've cleaned the puller threads you can try it again, but you'll need to thread it past the damaged section on the arm. You may need to use a wrench to get it fully threaded down. If it still strips, you'll have to use one of the Fred Flintstone methods of removing crank arms and either replace the arm or get it rethreaded to a larger size. VAR used to make a kit for this; I don't know if they still do.

jtarver

Funny, I had a similar prob pulling the stock Andel cranks off my LHT, I thought it was just me. I found I had to thread the puller in with a wrench until it bottomed out and used a cheater bar. I guess the same gorilla must have gotten to yours as well. I heard throwing some ice water or spraying some computer cleaner on it will work sometimes.

Panthers007

The newest crank-puller from Park Tool - CWP-7 - is beefier and stronger (thicker rotating tips) than their other, older offerings. The smaller diameter tip is also longer - it measures 11.38mm around and 9.15mm tall. I recently had occasion to remove my Campagnolo Super Record crankset. And it was like it was seized. I suspect my LBS had a hand, but that's another story. Any ways, it wouldn't budge for the Park CWP-6 - even using my 12 inch wrench. But the CWP-7 did it quite nicely - employing a ton of torque (almost) - and handled both crank-arms within moments whereas the CWP-6 simply refused to go there.

I'sd suggest every bike-mechanic actually purchase the new tool. It actually DOES make a difference. I, too, was skeptical at first.

Daboo

Yeah, it's hard to tell from the bad pic, but believe it or not it's actually the nut that stripped, not the crank arm threads. I gave it another go, and ended up further stripping the nut, and getting some of the nut thread squished in between the crank threads. The crank threads still look OK though. The first nut I stripped was off a CWP-6, and the 2nd off a CCP-22 (one with attached handle, which I believe has the same exact nut). I have to make a trip to the LBS today anyway, so I'm just going to bring it in and see what they say about it. This is my first time doing this too, so it really threw me for a loop Thanks for the help guys.

operator

That's impossible. I'm willing to bet a large sum of money that your crank extractor threads ARE stripped. There is onen critical error you made when employing the tool.

You need to thread this in by hand, then complete torquing it with a wrench - this is how most people strip their crank extractor threads.

You need to do this for *all* crank extraction attempts.

dperreno

I, too, find this hard to believe. The crank arm is made of aluminum, which is MUCH softer than tool steel. I'd be willing to bet that if you took a steel brush to your crank tool, you'd find that the threads are fine, but the grooves have been filled in with the stripped aluminum from the crank. Your tools should be good.

Daboo

Actually I did tighten the extractor nut as tight as I could on a previous attempt (before stripping the nut), but I wasn't getting anywhere. That's when I tried backing off a bit. Sheldon's site said it's bad for it to be either too loose or too tight, so I was afraid of tightening it too much.

operator

No such thing. Of course use your senses. 99.9% problems always come from having it too loose, not too tight. I don't understand why Sheldon would say such a thing.

Daboo

Here's some macro action for a closer look. I can also pick up the the shards of thread coming off the extractor nut with a magnet.

HillRider

Wow, something did indeed damaged those threads on the puller but I don't see how it could possibly be the aluminum crank threads.

FBinNY 

As someone mentioned, often a stubborn crank will work loose simply from riding. If you try that, be sure to install the crank arm bolt backed off about 1/2 turn, so the crank can pop loose, but not fall off. Afterwards try sprinting a steep hill in a big gear.

Definitely something besides the crank caused the remover threads to strip that way. If it was the result of the pulling force all the engaged threads would have to shear together, as there can't be a higher deflection in individual threads. I suspect an overhardened part that simply fractured & I'd replace it before trying again.

If the crank is indeed super hard to remove, don't damage it by using excessive torque of the puller bolt. Stubborn cranks can safely be removed with a pair of drill chuck removal wedges fitted behind the arm and pushing it away from the BB face. PM me if you need more info on that option.

Panthers007

Are you certain you deployed the correct (11.3mm tip) on the CWP-6?

Daboo

Yup, I had the correct tip on. LBS said the crank arm threads are stripped too, so I'm out of luck. The whole purpose for disassembly was to rustproof the frame. Since the crank is still fine, I just framesaved it with the crank and bottom bracket still in. I guess I must have crossthreaded the extractor nut or something...what kills me is not knowing what I did wrong

LWaB

Possibly the steel has been over-hardened and the threading has acted as a crack initiator. Still difficult to believe that it is the result of the aluminium thread but seeing is... etc.