Final Drive repair and adding two extra fasteners.

Woe unto you that bought the first model year of a major remake, perhaps this section can help address any 2014 and later model Ural "imperfections". Here's a special section for folks with the latest rigs to discuss 2014 and later model-related topics such fuel injection, 3-wheel disc brakes, hydraulic steering dampers, spin-on oil filters and other anomalies that don't belong on true Russsian motorcycle ;-P We've gone from using big hammers and greasy wrenches to needing computers and Ouija boards in order to fix our rigs.
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Please keep this section specific to issues pertaining to 2014 and later models such as fuel injection, sidecar and rear disc brakes and so forth. Ask general or non-2014 and later specific questions in the main Hammerin' & Wrenchin' section.
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rebelrider
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Final Drive repair and adding two extra fasteners.

Post by rebelrider » Sun May 06, 2018 8:00 pm

I've been sharing this on the Facebook group, but I thought I'd share here too so it doesn't dissappear. I heard there was another thread about adding two extra fasteners to bolt the FD to the swing arm, but I can't find it. I'd love to read it if anyone could share the link!

So this started with getting the speedometer drive gears replaced a while back, and the mechanic showed me that the FD bolts weren't torquing properly. I decided to approach the problem from two directions. Modifying and repairing the existing cover, and ordering a new cover.

Well starting out, I was under the impression that the fasteners in the cover were studs that were threaded into the FD cover. With them not torquing right, that implied that the threads inside were bad. But it turns out these are "special bolts" not threaded studs, and what has happened is that the head or flange of each bolt has sheared off and the bolts have pulled right through the cover without even spinning. I would have thought a dealer mechanic would know that. Also, I could have sworn my mechanic was attempting to torque the bolts to 35 ft-lbs, and it turns out it's supposed to be 35 NM.

Anyway, here's some pictures of my progress:
Image
The whole reason extra bolts are possible, is that there are these structural bosses (or whatever they're called) from back when Ural used to do 4 bolts, as I've heard.

Image
I picked up a drill and tap set and managed to drill the holes pretty darn close to the center of the bosses, and got it threaded for some steel inserts. I have some stuff like red lock tight and some Permatex stuff to keep them in place and from leaking oil.

Image
The holes in the swing arm were significantly more difficult. Not only because it is steel, but also none of my drills and bits were short enough to fit either side for a straight hole. In the end, I did manage to get them to line up by making them slightly oversized, and a lot of filing.

Image
Finally got all four fasteners in place.

Image
With the cover bolted in place, I was able to look at how the special bolts were behaving. At the time, I didn't know they were supposed to have flanges on the inside. At this point I saw that they were pulling straight out as I tightened the bolts on the other side. So I went ahead and pulled them all the way out.

Image
Here are the bolts removed. When I opened up the FD earlier, two metal rings fell out, and I wonder where they came from. Now I know they are the flanges from the bolts and at some point they sheared right off. Over-torqued at the shop I guess.

Image
Here's just a reference pic of some of the torque specs on my rig. This may differ from other Urals, as I've got an M70, and not a GearUp.

Still trying to decide how I will finish this.
Keep the modified cover and put two new special bolts in it, or make all four with threaded steel inserts?
Or drill the new cover I've got on order and put 4 special bolts in?

My confidence in these special bolts is pretty low right now. Anyone know if these hold up well when they're torqued properly?
I've heard of FD covers cracking, but mine is not damaged at all.
Mike
Image2014 Ural M70 "Trogdor"
1987 Honda CMX250C "Rebel"
1979 Puch Moped "Wasp"
1971 Honda SL100

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VWK75S
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Re: Final Drive repair and adding two extra fasteners.

Post by VWK75S » Mon May 07, 2018 5:28 am

Good thread :thumbsup:
Would replacing the original bolts with a stud that has an anti-rotation tab work? :?
John
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Re: Final Drive repair and adding two extra fasteners.

Post by Lokiboy » Mon May 07, 2018 6:55 am

Tomcatfixer did the same modification. Read his thread for comparison. He’s been riding for nearly a year with positive results.

It’s a long post, start around page 7
http://www.sovietsteeds.com/forums/view ... g&start=90

Nice job, BTY.
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Re: Final Drive repair and adding two extra fasteners.

Post by rebelrider » Tue May 08, 2018 12:21 am

Vwk75s: I don't think so. My issue isn't rotation, but the stud heads shearing off and pulling through.

Lokiboy: Thanks for the link. That thread made me think about the oversized holes I drilled into the swing arm. I hadn't thought about the whole FD rotating against the swing arm, but I think I'll have a way to fix that.

I think I'm gonna try putting 4 of the factory bolts in the new cover and see how that works out. I'll save my original cover and put 4 threaded inserts in it, but set it aside for in case the first attempt doesn't work.

From reading the other thread, It looks like a 13/32" drill bit will make a snug fit for the factory bolts. I'll have to go see if I can find one...
Mike
Image2014 Ural M70 "Trogdor"
1987 Honda CMX250C "Rebel"
1979 Puch Moped "Wasp"
1971 Honda SL100

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Tomcatfixer
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Re: Final Drive repair and adding two extra fasteners.

Post by Tomcatfixer » Tue May 08, 2018 5:05 am

There are many different ways to skin this cat.
I'm interested to see which approach you select.
:lurker:
- Chad

Virginia Beach, Virginia, USA

Current rides:
2015 Ural cT "Mobile Chernobyl", 1999 Ural Tourist "Desert DisGrace: the Iron (Oxide) Curtain", 1994 Honda VFR750F, 1986 Yamaha FZX700S Fazer

Previous rides:
2007 Honda VTR1000 FireStorm (Super Hawk in U.S.)
2001 Buell Blast! - - - - - - - 2005 Yamaha FJR1300
1993 Honda CBR600F2 - -1984 Yamaha FJ1100
1986 Yamaha FZX700S (a different one than above)

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Re: Final Drive repair and adding two extra fasteners.

Post by hotflash44 » Tue May 08, 2018 9:06 am

rebelrider i was wondering why you chose the 8.8 bolt over the 10.9 or 12.9 just curious. isn't stronger rate always better? :? :cheers:
drive a 2016 gear up asphalt grey .Air America CIA circa 1967/8 Vung Tau Viet Nam USS Tutuila ARG-4 (AND JUST A TOUCH OF AGENT ORANGE!)

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Re: Final Drive repair and adding two extra fasteners.

Post by Lmo » Tue May 08, 2018 12:11 pm

My $.02USD.

* Order four new "special bolts",
* drill the new cover for the extra two bolt (note the hole size BEFORE you drill the two extra holes (the special bolts are a 'press fit)),
* install the new special bolts and torque to spec.
* spring for the trick two-piece, wedge type Nord-lock locking washer ( Thanks for finding those BTW, Chad).

The addition of the two extra bolts will significantly reduce the stress on the existing two bolts and stabilize the final drive.

Why TF Ural doesn't do this in beyond me... two extra holes in the swing arm, two extra holes in the FD cover, and two extra bolts. Com'on, maybe $3USD in parts/labor = MAJOR product improvement.
Lew Morris
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rebelrider
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Re: Final Drive repair and adding two extra fasteners.

Post by rebelrider » Tue May 08, 2018 6:42 pm

I measured both the bolts and the original holes in the FD cover, and ignoring the splines, both measured to about 10.5mm. This works out to about 0.41 inches which is about what 13/32 works out to. I don't have a 13/32" bit so I'll have to get me one.

To answer your question Hotflash, I picked 8.8 bolts because they were what the hardware store had. Highly scientific, I know. :lol:

I wonder how much damage these broken bits of bolt would have caused if I hadn't decided to go ahead and open this thing up.
Image
Mike
Image2014 Ural M70 "Trogdor"
1987 Honda CMX250C "Rebel"
1979 Puch Moped "Wasp"
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Re: Final Drive repair and adding two extra fasteners.

Post by Snakeoil » Thu May 10, 2018 6:12 pm

You could check NAPA for metric wheel studs of the correct diameter and length. Then, you could machine the head down to the thickness of the original studs so it clears. I think quality studs would have a much reduced chance of head failure like you found with Ivan's studs.

I applaud your ingenuity on the threaded insert design. But, I suspect that they will not stay tight or last since the aluminum has been described by others as "yak cheese". I think having the stud compressing the FD housing rather than a bolt pulling on it via threads is a better idea. Just my 2 cents worth.
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Re: Final Drive repair and adding two extra fasteners.

Post by rebelrider » Sun May 27, 2018 8:30 pm

Finally got my part in. A new cover, bolts, and gasket from my dealer, and 4 bolts and some extra gaskets from russiangarage.com.
Image

The Russian bolts were M10x1 instead of M10x1.25. I decided to use the four in the new cover as a matched set. I also noticed the splash guard is twice as big as the original, so I had to drill a hole in that too. The 13/32" drill bit worked perfect.
Image

Here it is all assembled.
Image
Image

Fit perfect on the swing arm, and I even put some grease in the zerk fitting on the u-joint before I reinstalled it. Took me a few extra minutes to get the brake caliper back on. I took it off a while ago and forgot how things went back together. :lol: But there were no extra parts, and I took it for a test ride and it worked great.

The old cover with the steel inserts, I will finish up later and save as a spare.
Mike
Image2014 Ural M70 "Trogdor"
1987 Honda CMX250C "Rebel"
1979 Puch Moped "Wasp"
1971 Honda SL100

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Re: Final Drive repair and adding two extra fasteners.

Post by Tomcatfixer » Sun May 27, 2018 9:27 pm

Glad it worked out for you.
- Chad

Virginia Beach, Virginia, USA

Current rides:
2015 Ural cT "Mobile Chernobyl", 1999 Ural Tourist "Desert DisGrace: the Iron (Oxide) Curtain", 1994 Honda VFR750F, 1986 Yamaha FZX700S Fazer

Previous rides:
2007 Honda VTR1000 FireStorm (Super Hawk in U.S.)
2001 Buell Blast! - - - - - - - 2005 Yamaha FJR1300
1993 Honda CBR600F2 - -1984 Yamaha FJ1100
1986 Yamaha FZX700S (a different one than above)

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Re: Final Drive repair and adding two extra fasteners.

Post by chaos2 » Sun May 27, 2018 9:57 pm

and people say the 2wd needs more maintenance :D At least they used 4 bolts to hold it to the swingarm :cheers:
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