Repairing your own vehicles and machinery

[heavyhorse]

19 hours ago, littlejohn said:




..... parts which might not have needed replacement.

Many, many parts are sold that don't need replacement, as a means of diagnosing a problem.  As in "Try replacing the ******, maybe that will fix it".  If it doesn't, then buy some other part.  So increased revenue? 




Diagnosing an issue is pretty much a lost art, even where computerized aids exist.  One manufacturer that I am a dealer for sends out bulletins every few months warning servicers that their account will NOT be reimbursed when they submit warranty return parts that are not actually defective, that more than HALF of high-dollar parts returned are in good working order (or were before removal).  Implied: "So get your diagnosis correct or eat the bill, boys".