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:
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.
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.
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.
Finally got all four fasteners in place.
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.
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.
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.