Clutch snapped the crank

[Steelhead Slayer]

I just had a shop install a new primary clutch put on my 2012 pro. Went to the cabin for our annual family Christmas/ New Years outing and Bang! Sled went less than 5 minutes with my 11 year old son on it. Crank shaft snapped off right flush with the clutch. Bolt was falling out, I was able to remove it with my fingers. Any ideas why this could have happened? Installing a clutch is pretty basic work. Could the shop have over/under torqued the bolt? This has been a perfectly reliable sled with under 1500 miles on it. How could this happen?

 

[Sheetmetalfab]

I just had a shop install a new primary clutch put on my 2012 pro. Went to the cabin for our annual family Christmas/ New Years outing and Bang! Sled went less than 5 minutes with my 11 year old son on it. Crank shaft snapped off right flush with the clutch. Bolt was falling out, I was able to remove it with my fingers. Any ideas why this could have happened? Installing a clutch is pretty basic work. Could the shop have over/under torqued the bolt? This has been a perfectly reliable sled with under 1500 miles on it. How could this happen?

If it was way out of balance it could do that.
See if the clutch was assembled out of phase?

 

[MountainRider05]

I had my 12 do the same thing snapped the clutch off right at the shaft. I think its to do with under torqued. I have heard a lot of 12s that hav had that happen

 

[Murph]

If someone used an impact on removal or installation of clutch-- that could lead to failure.

Running an out of balance clutch for an extended period of time could have weakened the crank snub.

As soon as the crank broke the bolt would come loose, even if it was properly torqued.

Not a common failure, but not unheard of either, sorry it happened to you.

 

[rmlineman]

Rmlineman

Just broke my crank at the clutch on a 2011 800 pro hit a big rock under full power . Hit so hard it stopped the track for a second then snapped the crank right at the clutch. Too many rocks for this time of year down in the snowies

 

[pfi572]

Maybe damage was done before new clutch was installed if being it was replaced with new one?

 

[bigchevrolet]

There were two different cranks available on the early pros....most likely had the first model crank tolerances not would they should have been...I had one snap off and then received the new crank under warranty...about 3 months after warranty ended kudos to my dealer. This was with a balanced primary and weights dialed in within 1/10 of a gram

 

[ripnit]

Clutch out of balance or corrosion on the crank snout and or in the clutch tapper. Both need to be perfectly clean.

 

[mountainhorse]

The OP has not checked in on this thread since posting it up...
So lets give him a chance to answer some questions so we can help out.

Steelhead.... As you can see... there are lots of variables that could have caused your problem.

Could have been caused by previous damage to the clutch and/or crank snout.

Could have been caused by bad crank or bearings.

Could have been caused by removal of old clutch.

Could have been caused by poor fit or improper installation.

Could have been caused by an impact, blown belt, failed motor mount, poor alignment, or poor balance and many others.


Questions:

1) Why did the original clutch need to be replaced?

2) Did the original clutch break on the shaft (leaving the shaft and hub intact)

3) Did you buy a brand new Polaris Clutch or a used one? If used, what was the build date laser engraved on the clutch?
If new, was it a part the shop had to order in or did they have it "in stock"?

4) Did you ever blow a clutch belt on this sled?

5) Did you ever hit anything in the clutch area of the sled?

6) Did you re-torque the bolt, per factory installation instructions, once you had run the sled a short distance (mile or so)?

7) When it went "Bang" did the belt break at the same time?






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[AdrenalineAddict]

I'm convinced that the 80 ft/lbs. requested by Polaris makes the pro clutches nearly impossible to pull when the time comes to service them. I've seen a few failures since 2011 that have all come within 100 miles of either installing a new clutch or servicing a worn out clutch. I don't believe the stub can withstand the 700 to 1000 ft/lbs needed to pull one of those mothers off.

 

[mountainhorse]

Some come off easily, some do not... the 900's were spec'd out at 96 ft. lbs., and also came off with difficulty.

I no longer use the typical puller to remove the clutches and now use the hydraulic method.

I have, and use, the Perks "no wrench" clutch puller with water...some people are successful with a bolt. Hand force on the tool is all that I've needed on my machines. (I prefer Cascade Clutch Performance or Indy for Balancing and will only use them)

I also only fill the cavity by tipping sled on its side so no air is in the cavity.

http://perksbalance.com/products.html

This hydraulic method is more friendly to the crank and clutch as hydraulic pressure pushes on the entire pto snout... rather than just inside the bore of the bolt hole.

But... if the clutch hub is cracked or otherwise compromised prior to pulling... you can still break the clutch... but, IMO, better now than on the hill.

<iframe width="560" height="315" src="https://www.youtube.com/embed/Fp0aOxMU0W8?rel=0" frameborder="0" allowfullscreen></iframe>



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[sno*jet]

most guys who dont do there own maintnence and you ask them why, they tell you they want the dealer to make it right if theres a problem...
good luck!

ive always thought the removal process looked harsh.. its not a simple task sometimes, they often whack the puller with a big sledge..

I like the TRA for this reason.

 

[rags319]

Never did hydraulic method. Can you use clutch bolt or you need a longer bolt.

 

[B&M Fabrications]

We use a convention clutch tool that I seem to have splintered out the end of using it like I'm supposed to, and just shorten in up 3/4 of an inch or so. Tip the sled on its side and fill it into the threaded area for the puller, seal the puller with Teflon tape and install, use it just like you would normally. Works awesome and isn't nearly as hard on the clutch or crank.

Bryan

Sent from my SM-G928V using Tapatalk

 

[Vincenthdfan]

Some come off easily, some do not... the 900's were spec'd out at 96 ft. lbs., and also came off with difficulty.

I no longer use the typical puller to remove the clutches and now use the hydraulic method.

I have, and use, the Perks "no wrench" clutch puller with water...some people are successful with a bolt. Hand force on the tool is all that I've needed on my machines. (I prefer Cascade Clutch Performance or Indy for Balancing and will only use them)

I also only fill the cavity by tipping sled on its side so no air is in the cavity.

http://perksbalance.com/products.html

This hydraulic method is more friendly to the crank and clutch as hydraulic pressure pushes on the entire pto snout... rather than just inside the bore of the bolt hole.

But... if the clutch hub is cracked or otherwise compromised prior to pulling... you can still break the clutch... but, IMO, better now than on the hill.

<iframe width="560" height="315" src="https://www.youtube.com/embed/Fp0aOxMU0W8?rel=0" frameborder="0" allowfullscreen></iframe>



.

I never heard of doing it this way...what a great idea.

If it keeps from shocking and fatiguing the metal components more I am all for it....these machines need any advantage you can give them to keep from failing and stranding you out in the hills!!

 

[mountainhorse]

If using an old school puller as a "donor" bolt for the hydraulic method, I'd prefer to cut off most of the old puller pintle, allows for more fluid in the cavity... more fluid would give more even pressure on the entire snout... IMO.

On a really snug clutch... I've used the hydraulic method... and then heated the circumference of the clutch barrel (the part that the belt rests on when the primary is open and at rest)... with a MAPP gas torch... evenly... usually pops off in a couple of seconds...even the difficult ones.. this helps the clutch barrel to expand a bit and release easier.

I've also used some stout rubber truckers bungies to hold the clutch from "blowing off"... and I use a tie-down strap keep the clutch from turning... rather than a bar through the clutch... I want to be as gentle as possible.





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[mountainhorse]

Never did hydraulic method. Can you use clutch bolt or you need a longer bolt.

a
Can't use a clutch bolt as it screws into the crank... not the clutch.