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Repeatedly breaking jackshaft bolt

A
Aug 17, 2014
40
5
8
Hi,

I have a 2014 M8000. Since the beginning of the season I've broken 2 jackshaft bolts... the one that hold the secondary in place. After the first one broke, I replaced it with a 10.8 graded bolt and this one has broken off too!

I have a SSI proshift clutch kit with a torsion spring but it's been installed since 2015. I've thighten the adjustment to the 5th hole only since this season though, but it feels a little better adjusted that way.
http://www.bd-xtreme.com/index.php?id_product=605&controller=product

Anyone had any problems breaking this bolt repeatedly?

I'm not sure what to do at this point...
 

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cadeskii

Member
Lifetime Membership
Jan 19, 2012
86
12
8
Northern Mn
Does the clutch fit tight on the shaft? Don’t wobble?

Are you putting loctite on the bolt? I’ve had them come loose a few times and either had the bolt fall out or bend it some.
 
A
Aug 17, 2014
40
5
8
Does the clutch fit tight on the shaft? Don’t wobble?

Are you putting loctite on the bolt? I’ve had them come loose a few times and either had the bolt fall out or bend it some.

Yeah, that might be the issue. I neglect to reapply loctite whenever I remove this bolt.

I'll try to measure the broken bolt and determine if the bolt broke after backing off or when it was tight.

I've never had a bolt fall out so I though the lockwasher was doing a good enough job that I didn't really need loctite.

Thanks!
 

daknapp

Member
Premium Member
Aug 29, 2013
33
6
8
Adirondacks, Northern NY
Just had this happen on my '14 High Country during week one of a two week trip to Wyoming. To make matters worst I broke a drill bit off in the bolt in an effort to get the bolt out. Ordered a new jack shaft and had it shipped on to Alpine for our second week (as we were at Albany Lodge) only to discover that the upgraded shaft was no longer drilled and tapped at the gear end...and because I was running a TKI belt drive then had to have the (hardened) shaft drilled and tapped. Many thanks to Troy & Rich at Lincoln County Customs for getting me back underway by doing the drilling & tapping !!! Fortunately we had a spare Summit to ride.
 

boondocker97

Well-known member
Lifetime Membership
Oct 30, 2008
4,053
2,764
113
Billings MT
Plenty of blue Loctite and a good lock washer (not squished flat without pressure on it) are required to keep that bolt tight in my experience. I carry a spare in the tool kit in case it does come loose and bend.
 
F
Nov 5, 2017
136
54
28
Nevada
Over stretching the bolt or shearing it off.
Putting anything on the threads will make your torque reading inaccurate. Bolts clamping force is measured by the amount of stretch in the fastener. Since you are not going to be tightening it to x amount of length they give you an estimate of the torque reading. Less resistance to tighten it if it's lubricated but the max effective clamping force is achieved. Hence arp only gives torque readings using SPECIFIC things on the threads. Their own torque lube and loctite.

Shearing it, clutch wobbly, loose splines, ect.

Ultimate setup would be a stud hand tighten into the shaft. A spacer pushing on the belt deflection setup and then a lock nut. The spacer is to give you just a little bit more of the stud to increase your clamping range.

Im probably over thinking this.

buy a stronger bolt, dont tighten it that much, and make sure the clutch isn't wobbling on the shaft.
 

Teth-Air

Well-known member
Lifetime Membership
Premium Member
Nov 27, 2007
4,548
2,776
113
Calgary AB/Nelson BC
www.specified.ca
Hi,

I have a 2014 M8000. Since the beginning of the season I've broken 2 jackshaft bolts... the one that hold the secondary in place. After the first one broke, I replaced it with a 10.8 graded bolt and this one has broken off too!

I have a SSI proshift clutch kit with a torsion spring but it's been installed since 2015. I've thighten the adjustment to the 5th hole only since this season though, but it feels a little better adjusted that way.
http://www.bd-xtreme.com/index.php?id_product=605&controller=product

Anyone had any problems breaking this bolt repeatedly?

I'm not sure what to do at this point...

Do you have room for a bigger bolt? On my Proride driveshaft I drilled and tapped larger and put a stud in with 2 nuts to lock. No problems.
 
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