Originally Posted by
maddog34
the screw threads are corroded to the aluminum dropout... that is why the screw broke.
the stub sticking out is buggered up from attempts to do what so many say can be easily done.
the corrosion will need to be broken loose before that screw will ever turn.
drilling and a properly sized easy out is the best course, After more penetrant, and/or heat cycling is applied.
too much heating will damage the paint in a 1 to 2 inch radius... or more.
^^This. With the added comment: Take a hammer and round punch, perhaps 3mm diameter, and hit the bolt (axially) stoutly from each side, in an attempt to drive the bolt across any slack in the threads, to loosen the bolt. Back and forth, alternating hitting from both sides. DON'T use a pointed (center) punch, that will make the bolt ends tighter. Then try to turn it somehow.
I had a bolt break off flush, it was a long rack bolt and probably came loose. Fortunately, using a dental pick, I was able to back out the threaded portion as it was not tight and was lubed with anti-seize. AFTER THAT... I replaced all rack bolts with ones that protruded to the inside by at least a nut thickness. So...
- If the bolt breaks, I can grab the other end to back the bolt out.
- After normally tightening the bolt, I put a nut on the protrusion end and torqued it mildly, to lock the bolt in place. Never comes loose. But if needed to, it is anti-seized to come out easily.
- Use stainless steel bolts.
- Torque to spec with a micro-torque-wrench, if you have one.
- Mark 12 o'clock position of bolt head as easy indicator if bolt is coming loose.
"Go in peace." - Jules, Pulp Fiction