Make sure no existing constraints are preventing the movement (suppress or delete those that do), then use a 40 deg constraint, preferably with the (3rd) option for explicit reference vector to make sure it turns in the direction needed:
Make sure no existing constraints are preventing the movement (suppress or delete those that do), then use a 40 deg constraint, preferably with the (3rd) option for explicit reference vector to make sure it turns in the direction needed:
