[Scarebird]

I ran into that sort of thing all the time researching brake conversions. Mopar was especially bad using multiple sizes differing little when one size would do the task fine.

I always thought that a good assembly engineer would design a setup that drunk idiots could assemble easily. Then we have the 1970-73 Firebird front bumper...

[Shiny]

Originally Posted by Scarebird

I ran into that sort of thing all the time researching brake conversions. Mopar was especially bad using multiple sizes differing little when one size would do the task fine.

I always thought that a good assembly engineer would design a setup that drunk idiots could assemble easily. Then we have the 1970-73 Firebird front bumper...

I never worked in automotive but respect what they accomplished and like to imagine their world. I really enjoy the manual drafting and hand-written revisions.

My guess: Some development/design engineer picked a short bolt because it was "right". It fit the assembly and saved money on the BOM cost. Then some manufacturing and/or quality engineer got tired of managing two part numbers and watching the line workers waste time sorting and getting told the bolts had been installed wrong. Then some purchasing guy negotiated a lower price on the long bolts by promising more volume to the supplier if the short one could be eliminated.

What I'm guessing didn't happen well was the manufacturing review of the new design. They probably didn't have time to deep dive every fastener and relied on early manufacturing experience to disclose issues and opportunities. The manufacturing team was probably under serious stress just to get a new design running at all. Once they saw the bolts were dog point where misalignment was probable, they may not have questioned the length. As you say, the line worker could get it done.

It's amazing in today's world to think they could ship a car that didn't 100% conform to a known design revision. Then again, vertical integration was pretty good at cutting corners and getting stuff done fast. A lot easier to have a revision discussion by walking to the line than hopping on a plane to visit an overseas supplier and dancing around proprietary information.