Our county transportation mechanics have been very forthcoming when I visit (bring donuts) and probe for details about Freddy D. Maybe the mechanics who have been working on yours for the past decade could provide details.
Your drawings are a terrific communication tool, so any school bus maintenance facility will understand your question. It may be a standard repair.
Keep us posted, I'm sure you are not the only one who wants to know.
"If there is no struggle, there is no progress."