Originally Posted by
robert schlatte
It is okay to use the same eyelets the fenders are on. I did that on my bike to get the rack level.
+1
Originally Posted by
FBinNY
Yes, it's find for racks and fenders to share a mounting bolt. When doing so, the rack goes first so it's load creates the same shear forces on the bolt as otherwise, and the fender which is basically zero load, goes to the outside. Because fender braces can spread, I use a washer between them and the rack, and also under the bolt head.
An old touring friend does it a bit differently, threading a long pan head from the inside out and tightening it to the frame, then the rack held on with it's own nut, followed by the fender with a nut, and finally sawing the rig flush and filing it smooth. The reasoning is that it assures that the frame won't ever be stripped, and the separate nuts, give early warning that things are getting loose while the rack is still secure.
If you go with my friend's belt and suspenders solution, finish by using a center punch on the screw/nut face, to distort the last thread slightly and preventing loosening. You only need a bit for it to be secure (test by trying to back off gently), but the nut can be removed easily enough when desired.
I've done the same, except I used
nyloc nuts and/or blue Loctite.
In a pinch, Krazy glue (cyanoacrylate) works too as threadlocker, but it'll sometimes dissolve plastics and occasionally foul bolt threads to the point where a cleanup with knife edge required.