What is the diameter of the bolt at the failure point? It's hard to gauge the size in the photos.
The taper fit should keep the bolt from wallowing in the arm, but any load support provided by the shoulder would be lost if the taper locked in first. If the shoulder makes full contact before the taper locks in, the benefits of the taper are lost. In other words, a proper fit would require absolute precision on both the bolt and the steering arm, something that seems almost impossible in a production situation. Once it is assembled, visual inspection isn't very useful, because the failure point will be hidden from view.
I'm not a metallurgist, but my limited experience with stainless hardware has been that the threads tend to gall and seize when torque is applied, and this causes the bolt to fail when disassembly is attempted.
Bill in FtL
Bill, my thoughts too.
If the taper hits first there will be a slight gap under the upper support and likewise if the taper is not met.
My thoughts on this would be, just like most heim joint applications, a through bolt, possibly an Allen grade 8.
I would use a bolt through the heim joint, through the collar support extension and then through the steering arm and fender bracket. Based on the taper in the steering arm, I would turn down a tapered sleeve that would be bolt size ID and then fit the taper. The bolt would just run through the taper sleeve.
The entire assembly could then be torqued down very tightly.
Streetrod, off-road vehicles all use heim joints on the steering and they are all through bolted to the steering arms.
Didn't the "comfort kit" from M3W just use a through bolt in their kit even though the steering arm has the taper? I've not heard of any of them breaking off.
