Shimano Crank problem

[lumpy]

Hi all,

I have a new Shimano crank with a problem. After my LBS installed it along with a new BB, the drive side got loose on a ride. I tightened it up as soon as I got home but it now doesn't seem to stay tight. It gets loose after about 10 miles no matter how tight I make it.
It has the "Octalink" splined interface by the way.
Anyway, I've been told that once they get loose and you ride, the aluminum gets pounded and there is no way to save it. Too much play develops and you can't eliminate the slack.
Needless to say, I'm a bit ****** at the prospect of having to buy another crank arm.
One shop told me to use "Loctite" on the threads as that may help. (It seems Shimano says to use grease on installation, but Campy insists on thread locking compound).
I'm thinking of trying some "JB WELD" or other similar viscous epoxy to take up the slack before I chase down another crank arm.

Anyone ever face this problem and have any advice?

Thanks,
Tim

 

[Duckwah]

if its a new crank then it should be a warranty issue

i'd avoid any epoxy since it will make it imposible to repair later

get your LBS to fix it

 

[GuyStevens]

Did the crank arm become completely loose on the bottom bracket? If so, your LBS is at fault. Shimano splined bottom brackets and cranks need to be carefully aligned and then fully engaged before tightening the crank bolts.

If the aluminium splines on the crank are shredded there is nothing you can do. Get your LBS to replace free of charge (and a freebie for the hassle!)

 

[lumpy]

Thanks for the replies,

It is a new crank, a hard to find XT with 172.5 length. It came pretty loose to where there was side to side wobble - so the octalink splines are damaged I'm sure.
The problem is I doubt my LBS will help even if I back them up against the wall. Yeah I know it's their fault, but they won't get me a new crank. They'll surely do free labor but like I want that?

I knew I should have done it myself - I'm a machinist by trade ... argh!

I'll pull the arm today and see how much damage there is and my next step.

I suspect I'll use the "JB Weld" and medium "Loctite". The JB won't act as a glue, instead it will fill in the gaps and hopefully eliminate the slack. Nashbar still has some cranks left so I may place an order. We'll see what things look like.

Thanks again for the replies,
Tim

 

[drewski]

Originally posted by lumpy
I suspect I'll use the "JB Weld" and medium "Loctite". The JB won't act as a glue, instead it will fill in the gaps and hopefully eliminate the slack.

You sure that it won't act as glue? I've use JB Weld to repair some automotive stuff and there's a reason it's called Weld

 

[boudreaux]

Originally posted by lumpy
Thanks for the replies,


The problem is I doubt my LBS will help even if I back them up against the wall. Yeah I know it's their fault, but they won't get me a new crank. They'll surely do free labor but like I want that?



I suspect I'll use the "JB Weld" and medium "Loctite". The JB won't act as a glue, instead it will fill in the gaps and hopefully eliminate the slack. Nashbar still has some cranks left so I may place an order. We'll see what things look like.

You are giving up too easy of the LBS being responsible and likely kidding yourself about the JB weld and any satisfaactory permanent fix.

 

[lumpy]

Went for another ride before doing a teardown. The locking allen nut comes loose and allows the movement between the splines where the wear took place.
I'm trying just blue loctite first to see if that does the trick. I've also got the red if it looks like I'm on the right track.

I don't want to go toe to toe with my LBS yet until I've investigated all my options. He's a friend and I don't want to sour things that are more important than a crank. That's why I posted here to see if anyone has faced the same problem.

As for the JB Weld, the trick is to use extra hardener - about 2X - to diminish the sticking strength.

Thanks guys,
Tim

 

[Roadant]

I am experiencing the same thing with an old Dura Ace crank arm that I bought on Ebay. Maddening, isn't it?

 

[boudreaux]

Originally posted by Roadant
I am experiencing the same thing with an old Dura Ace crank arm that I bought on Ebay. Maddening, isn't it?

If the spindle holes in the arms are trashed,they never will stay tight. On square tapers,a beer can shim is often a temp fix.

 

[BaCardi]

Originally posted by boudreaux
If the spindle holes in the arms are trashed,they never will stay tight. On square tapers,a beer can shim is often a temp fix.

A beer can shim, however temporary a fix, is a poor solution and never a good idea in this case. Did you even bother to read the entire thread? Didn't think so.

 

[boudreaux]

Originally posted by BaCardi
A beer can shim, however temporary a fix, is a poor solution and never a good idea in this case. Did you even bother to read the entire thread? Didn't think so.

If you read the entire thread you would see a second crank with square tapers being mentioned. Admittedly an assumption based on it being 'old'. A shim can work, often for a long time depending on how bad the problem is, free and beats just tossing a crankset......You are wasting your time rying to get over on me.You don't have the stuff upstairs.

 

[BaCardi]

Originally posted by boudreaux
If you read the entire thread you would see a second crank with square tapers being mentioned. Admittedly an assumption based on it being 'old'. A shim can work, often for a long time depending on how bad the problem is, free and beats just tossing a crankset......You are wasting your time rying to get over on me.You don't have the stuff upstairs.

WRONG! Don't listen to this guy.

A beer chan shim is a temporary fix at best and is never recommended for usage for a long time.

 

[boudreaux]

Originally posted by BaCardi
WRONG! Don't listen to this guy.

A beer chan shim is a temporary fix at best and is never recommended for usage for a long time.

Why? Catastrophic failure?

 

[lumpy]

Update:

Took it back to my LBS and he took it all apart including the BB and reinstalled it. The kid who initially put it together used so much grease that it looks like the grease kept things from seating properly. The splines are a bit rounded but there is no detectable play and so far it's staying tight.

Tim

 

[boudreaux]

Originally posted by lumpy
Update:

Took it back to my LBS and he took it all apart including the BB and reinstalled it. The kid who initially put it together used so much grease that it looks like the grease kept things from seating properly. The splines are a bit rounded but there is no detectable play and so far it's staying tight.

Tim

That business about too much grease is just total hooey. The grease squeezes out when the crank is seated on the spindle. the idiot kid put it on wrong and likely did not have the splines lined up right, or did not torque it properly. You may still have trouble.

 

[lumpy]

Originally posted by boudreaux
That business about too much grease is just total hooey. The grease squeezes out when the crank is seated on the spindle. the idiot kid put it on wrong and likely did not have the splines lined up right, or did not torque it properly. You may still have trouble.

That's fine assuming the grease has a way to go to get out. If it doesn't then it can't be compressed. I think it was initially tight and almost fully seated but up against just enough grease to prevent full seating, then the grease slowly worked out and that allowed it to loosen up. There is no way he didn't have the splines lined up - the drive side would have been sticking out over 1/2"

Regardless, now that all the grease is out of there, it torques up just fine and stays tight.

Tim

 

[boudreaux]

Originally posted by lumpy
That's fine assuming the grease has a way to go to get out. If it doesn't then it can't be compressed. I think it was initially tight and almost fully seated but up against just enough grease to prevent full seating, then the grease slowly worked out and that allowed it to loosen up. There is no way he didn't have the splines lined up - the drive side would have been sticking out over 1/2"

Regardless, now that all the grease is out of there, it torques up just fine and stays tight.

Tim

With all due respect,if you knew anything and had ever even looked at one you would know it has a 'way out'.You just had a bunch of smoke blown in you.Enjoy.

 

[drewski]

Originally posted by boudreaux
With all due respect,if you knew anything and had ever even looked at one you would know it has a 'way out'.You just had a bunch of smoke blown in you.Enjoy.

though a bit harshly worded, i have to agree.

maybe they realized they f****d up and put in a new crank-arm sans spline wear and to save face they gave the ole "grease excuse".

 

[BaCardi]

Originally posted by boudreaux
With all due respect,if you knew anything and had ever even looked at one you would know it has a 'way out'.You just had a bunch of smoke blown in you.Enjoy.

Look at this comment. What a f-ing asshole. Just say they screwed up and quit acting like you know it all, which by the way you certainly do not.

 

[boudreaux]

Originally posted by BaCardi
Look at this comment. What a f-ing asshole. Just say they screwed up and quit acting like you know it all, which by the way you certainly do not.

What a 14 year old potty mouth. Peter sure did call it right.