I was installing a hitch on said vehicle... what should be an easy function. Anyway... there are 6 bolts holding rear rupport to the frame. 8mm (about 5/16 thick) not very thick at all.
Anyway.... not rusted, I applied normal torque, the head snapped off on one. Removed a couple.... head snapped off on another.... removed another and the head snapped off of the third.
Okay.. I'm used to car manufacturers building their products so they can't be disassembled. However the bolts were not rusted, absolutely no reason why they should snapped... (except for some paint overspray).
My speculation is that these bolts have a low shear strenth as they seemed to have a gray powdered appearance. Any reason why...
Second, even though they have a low shear strength, the remaining stud is difficult to remove. I've tried the usual vise grips., easy outs, stud removers and other devices. studs will not turn. I'm planning on drilling them out, but the material seems to be too hard for regular steel twist drills.
So, anyone know what the story is on the type of bolts used to hold the rear bumper assembly in place.... why so weak ?? Is this to make it difficult to remove and replace the rear bumper in case of an accident... thus isnuring replacement. (Between the auto manufacturers and the government, I'm beginning to sound like a conspiracy nut !!)
Second, what's a good type of drill bit to use to drill these puppies out... what type of tip material would be hard enough ??
Thanks !!
Peter