I'll second the heli-coil approach... Unless locktite makes a compound that'll do the job. That green locktite stuff works almost as good as welding a bolt right in there once it cures. Although you may never get it apart again if you need to.
You sure there 1/2 "?
The studs I have seen including mine that hold the side brackets on are 5/8.
The bolts that hold the end case on are 1/2",are we referring to those?
TGP
Edit - thread I.D. mikes 0.470 inch and 1/2-13 tap fits 7 of the 8 holes, but the 8th one is just a bit loose.
5/8 tap is way to big to even enter the hole, much less the threads.
2nd Edit -- LU-4 Manual calls for 9/16-12 double ended studs 2-5/16 long
Dorman 675-046 is 9/16-12 and fits, but is 2-1/2 long. Both stock and Dorman have 3/4" long threaded section.
I just checked my end caps, and the 9/16-12 Dorman does fit.
What am I missing re the 5/8"?