Pittsburgh-based Rockwell International posted record sales and earnings for the firm's 1986 fiscal year that ended Sept. 30, including earnings increases by its aerospace and electronics businesses. However, automotive and general industries earnings were lower than a year ago, principally due to market weaknesses, the company said. Full year results benefited from vigorous cost-reduction actions throughout the company, a spokesman added. The 1986 year marks the 11th consecutive period in which Rockwell earnings have increased and the third consecutive year in which the company exceeded a 20% return on average stockholders' equity. These results are particularly encouraging, the spokesman said, considering the fourth quarter included the adverse effect of approximately $40 million before taxes for plant and product-line restructuring.