Disc question

cudamark said

They went from 9" drum brakes on some low level A-bodies to 10" drum brakes as that service bulletin shows, but, the upper ball joints, lower ball joints, wheel bearings, and spindles stayed the same from the beginning of the model year. Just the hub and drum assembly and the backing plate assembly changed. And NOTHING from a '72 and earlier was used except the bolt pattern. This was all changed right at the model year changeover Aug 1st.

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We’ve had this conversation before. What you’re suggesting makes no sense from an engineering or production standpoint, because some of those parts would have needed to have been produced for only a 3 month run.

Never mind that there’s a long, fairly well documented history of Ma Mopar running the previous model years parts until they ran out if they weren’t specifically cosmetic model year changes. Hell my August built ‘72 Challenger has a whole bunch of “1971 only” original parts on it.

Still, if you want to show me a 9” hub and drum assembly that uses large wheel bearings I’m game. Or even a 10x2.25” drum assembly with large wheel bearings. Until then I’m going with logic, documented past practice and the TSB.

***Edit***
Corrected 10" drum dimensions to front drum dimensions