On Tue, 11 Apr 2006 17:13:39 -0500, Wayne
wrote:

A friend of mine (really!) went to remove a mirror
from his motorcycle. The mirror mount is steel and
mounts to the front brake master cylinder (aluminum).
There is a recess in the mirror into which an allen
head bolt holds the mirror to the master cylinder.
He broke the allen wrench flush to the top of the
bolt. The head of the bolt is recessed to where
you can't get at the sides of it. The bottom
of the bolt is visible on the underside of the
master cylinder.

The only way I can think of to fix this is to
take the master cylinder off, turn it upside down.
Then drill through the bolt from the bottom side.
Then take a punch and knock out the allen wrench.
Then use an impact to take the bolt out.
We'd have to fill the master cylinder full first
so air doesn't get into the line when flipping
it over.

This sounds like a lot of work. Anyone have any
easier suggestions?

His original problem is the mirror keeps loosening
up on the 'stalk'. The ball on the 'stalk' is ridged.
That sits in a plastic piece. By moving the mirror
you can see where the plastic is falling apart in
the ridges. He's already replaced the mirror several
times. Is there any kind of goop that could be put
in there which would hold the mirror, but still
allow movement?

Wayne D.
As far as the wrench goes I can think of two things. First, use a
punch to mark the center of the wrench. Banging on it may loosen it.
After using the punch drill a hole that's the tap drill size for a
thread size smaller than the wrench, but not by much. Tap the wrench
stub. Even though the wrench stub is hard, a tap is harder. The
tapping process will probably loosen the wrench stub if the drilling
doesn't. Or, after drilling the hole, use an impact screwdriver with a
phillips bit in the hole. Impact screwdrivers, the kind you hit with a
hammer, can be had pretty cheap, like 10 bucks. If you already have
the impact wrench, and it sounds from your post that you do, then
you're set. Before using the impact wrench on the screw itself maybe a
little oil and heat could be used first. I think drilling from the
back side is way too much work. I bet that wrench stub pops out when
you start to work on it.
ERS