I can understand from your 1955 answer what the difficulty is and why fourth year gets so much flack. Prior to 1990, mechanics could engineer many of their jobs themselves by installing ‘good-enough’ replacements. Since then, liability has made it impossible to work with other than factory approvals and code compliance. Common practices of the older time are now not good enough. Prudence dictates that responses be based on code compliance and factory specification, no longer on ‘common practices’ and OJT prior generation practices.
It took me a while to accept this responsibility and I receive flack from DIT’s who do not realize this change. Professionals who have not accepted this imposition on their ‘freedom’ may be doing frequent disservice and the ones who have accepted this change criticize.