Removing Broken and Stuck Head Bolts
One head bolt had been twisted off flush with the head some time
in the past. The job at hand was to remove it without damaging the
block. Here’s how I did it.
First step... find the exact center of the remaining stub. I used the
head for a drilling guide, clamped in place by a couple bolts. I used
a drill bit the exact size of the hole in the head, which is letter
size X, .397".
The result was a dimple in what should be very close to the center of
the stub.
Next, the drill guide is set in place by feeling for the center of the
dimple with the end of a drill shank that just fits the guide. Then
the guide is clamped in place. Next the same drill is used to drill a
pilot hole down the center of the stub. The drill guide will assure
that it is drilled in the center and perpendicular to the block.
The hole can be step drilled in increasing sizes using a similar
guide up to the tap drill size, and a tap used for final cleaning of
the threads.
So here’s the final result… SUCCESS!
