Final drive breakdown - repair or replace help

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Re: Final drive breakdown - repair or replace help

Post by wildhair523 » Sat Jul 06, 2019 9:20 pm

Yep, I couldn't believe there wasn't more damage with all the hardware flinging around in there.
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Re: Final drive breakdown - repair or replace help

Post by jaybird » Sat Jul 06, 2019 10:35 pm

By the looks of those bolts, that thing had to be "clunking" for quite some time.
I don't see any broken teeth pieces in that swarf, what does the ring and pinion gear look like?
So far it looks fixable for a local or off road rig, or as a spare. If the gears are not missing any full teeth and just chipped or not damaged at all, with a tube of JB Quick and some new bolts, you could be back on the road tomorrow. :cheers:

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Re: Final drive breakdown - repair or replace help

Post by VWK75S » Sun Jul 07, 2019 5:44 am

Wonder what happened :?
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Re: Final drive breakdown - repair or replace help

Post by harryball » Sun Jul 07, 2019 6:30 am

Wow. Looks like the bolts were never torqued and they all came out! I'm surprised the teeth are not all damaged too.
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Re: Final drive breakdown - repair or replace help

Post by wildhair523 » Sun Jul 07, 2019 7:02 am

jaybird wrote:
Sat Jul 06, 2019 10:35 pm
By the looks of those bolts, that thing had to be "clunking" for quite some time.
I don't see any broken teeth pieces in that swarf, what does the ring and pinion gear look like?
So far it looks fixable for a local or off road rig, or as a spare. If the gears are not missing any full teeth and just chipped or not damaged at all, with a tube of JB Quick and some new bolts, you could be back on the road tomorrow. :cheers:

Happy trails,
Jaybird
Nope - there was no clunking prior to the first metal grinding noise, no noticeable change in shifting, power, etc. The first noise occurred after climbing a long hill - when I backed off the gas and started downhill. A loud BAM followed by several second of metallic grinding. Then it ran fine again until there was a 2nd loud BANG, a minor lurch (like you were running out of gas), I felt something hit my right leg, then an odd hissing noise (I now suspect was fluid from the final drive hitting the exhaust) - then it was quiet again. I sped up and slowed down - no more noise. I was doing 55 mph as I came into town. Got all the way thru town and when I tried to pull away from a light - then it sounded horrible - like bolts in a blender.

None of the teeth are damaged on the ring or pinion gear, but 7 of the 8 bolt holes are stripped out of the ring gear, so I won't be using that again. Pinion gear is fine, needle bearing are fine. I intend to fix it as a spare. Most of the swarf is aluminum from the case - I went over it with a magnet. There are a LOT of pieces from inside the case broken of - that needs to be replaced, too.
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Re: Final drive breakdown - repair or replace help

Post by rivers » Sun Jul 07, 2019 1:22 pm

wildhair523 wrote:
Sun Jul 07, 2019 7:02 am

None of the teeth are damaged on the ring or pinion gear, but 7 of the 8 bolt holes are stripped out of the ring gear, so I won't be using that again. Pinion gear is fine, needle bearing are fine. I intend to fix it as a spare.
If the ring gear is toast you'll also need to replace the pinion. They're a matched set and wear in together. Mixing used R&P pieces or even new with used is a recipe for failure.
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Re: Final drive breakdown - repair or replace help

Post by Lokiboy » Sun Jul 07, 2019 3:40 pm

harryball wrote:
Sun Jul 07, 2019 6:30 am
Wow. Looks like the bolts were never torqued and they all came out! I'm surprised the teeth are not all damaged too.
An alternate theory, mine, is that sometimes the bolts are torqued too much. Absolutely no flexibility which causes too much stress on the heads thus causing them to shear off.

I didn’t stay at a Holiday Inn so I may be way off base

I’ll find out, because when I put my FD back together I just did a snug and about a half turn using blue Loctite.
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Re: Final drive breakdown - repair or replace help

Post by wildhair523 » Mon Jul 08, 2019 6:46 am

rivers wrote:
Sun Jul 07, 2019 1:22 pm
If the ring gear is toast you'll also need to replace the pinion. They're a matched set and wear in together. Mixing used R&P pieces or even new with used is a recipe for failure.
I hadn't heard that before, but it makes some sense. I'll ask Terry Crawford about that today. Thanks.
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Re: Final drive breakdown - repair or replace help

Post by Msblu79 » Mon Jul 08, 2019 9:21 am

The bolts should be torqued until they are stretched and cannot move/flex under load. I torqued mine to 25lb/ft and used red loctite. To little torque and the bolts will "work" until the heads snap off, stretch the shank of the bolt to prevent failure. Use 12.9 grade hardware as well for best results. :)
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Re: Final drive breakdown - repair or replace help

Post by wildhair523 » Fri Jul 12, 2019 10:59 am

7/12/19 - Update - rather than start a new thread.
The new final drive is in and it comes with a new donut, new driveshaft and new brake shoes. The donut on mines is worn (holes elongated) and should be replaced, so I'll do that and may as well put in the new driveshaft as long as it's apart.

Trying to do my homework and reading thru previous posts, I could not find much on driveshaft replacement. REGARDING donut replacement for a 2013 - looks like I need to remove the swingarm and shocks to replace the donut & the driveshaft.
(viewtopic.php?f=12&t=49808&hilit=swinga ... 3&start=45 )
I printed out post from page 3 with a detailed step-by-step.

Is that correct? Any tips or tricks to pulling the swingarm? I read using silicone or dish soap will help the tabs or fingers go into the new donut easier.

I also read about "driveshaft alignment and phasing" and I want to make sure I got this right. To correctly phase the driveshaft - Are the "fingers" on the donut (transmission) end of the driveshaft aligned with the yoke on the splined end of the final drive u-joint? I've slipped the driveshaft into the splined yoke and I cannot get them aligned. However, I can align the phalange with the fingers (donut) with the u-joint attached to the FD.

There doesn't appear to be anyway to adjust the alignment that I can see.
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Re: Final drive breakdown - repair or replace help

Post by Mr Wazzock » Fri Jul 12, 2019 11:08 am

Yes when I needed new speedo drive, meant replacing the gearbox output yoke so FD & shaft had to come out as well, so we had to shift the swingarm back to make room. Easiest was to remove the pivot bolts then slide it back, leaving the shocks in situ. Only thing about that tho, they need compressing a bit (e.g. ratchet straps) because otherwise the swingarm fouls on the stop rubbers on the frame and is difficult to move.
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Re: Final drive breakdown - repair or replace help

Post by Mr Wazzock » Fri Jul 12, 2019 11:12 am

"This is the best alignment I can get"
It's not unusual that the yoke "fingers" and UJ fork don't line up exactly, so yes you just have do the best you can. I presume you've tried it both ways i.e. turned 180 degrees?
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Re: Final drive breakdown - repair or replace help

Post by Msblu79 » Fri Jul 12, 2019 11:22 am

Mr Wazzock wrote:
Fri Jul 12, 2019 11:08 am
Yes when I needed new speedo drive, meant replacing the gearbox output yoke so FD & shaft had to come out as well, so we had to shift the swingarm back to make room. Easiest was to remove the pivot bolts then slide it back, leaving the shocks in situ. Only thing about that tho, they need compressing a bit (e.g. ratchet straps) because otherwise the swingarm fouls on the stop rubbers on the frame and is difficult to move.
I have found that if I rotate the shock spring preload collars to minimum setting that it helps reduce the drag on the swingarm bumpers. :)
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Re: Final drive breakdown - repair or replace help

Post by wildhair523 » Fri Jul 12, 2019 11:29 am

Mr Wazzock wrote:
Fri Jul 12, 2019 11:12 am
"This is the best alignment I can get"
It's not unusual that the yoke "fingers" and UJ fork don't line up exactly, so yes you just have do the best you can. I presume you've tried it both ways i.e. turned 180 degrees?
Yes, flipped it 180 - it's slighted canted and not in alignment with the yoke at the other end.
So - just get it as close as I can? It does align with the U-joint attached to the FD, but then it's almost perpendicular to the yoke. Which I read somewhere is not good.

Thanks for the advice on the shock pre-load.
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Re: Final drive breakdown - repair or replace help

Post by Mr Wazzock » Fri Jul 12, 2019 12:02 pm

No it must align with the fork on the end of the driveshaft, not the one on the FD input shaft. Or as close as you can get it.
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