Neil,
You just need to bite the bullet , or in your case SPRING. Just undo those bolts & let it fly.
JUST A THOUGHT .You could make up a board with two blocks of wood screwed to the board with the gap the same width as the shaft or a bit wider , secure the housing to the board then undo the screws. That way the spring can only expand as far as the blocks, then the will be less tension on the spring.
Wayne
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