The former head of Valiant body engineering told us how axles were designed “back in the day” and how they switched to their 1960s-1990s design—and what he would have done differently!
#mopar #axle #valiant #plymouth #dodge #classiccars #rearaxle #autohistory
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hi this is Dave from motels and I'm here
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to build on Pete Do's recent talk about
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axles my story here is actually Al
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Bosley's Story the axle is surprisingly
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one of the items on a car which requires
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the longest lead to set up tooling so
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the Valiant axle was planned before the
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details of the engine or transmission
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were known in early 1957 in fact Al was
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responsible for the rear axle the
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drivetrain and the rear suspension even
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though he was still a pretty young
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engineer new to the company the front
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and rear suspension designs were then at
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different departments at Chrysler this
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is kind of an odd idea since they really
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do have to work together Evan Jones was
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the manager of the axle lab and he had a
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great deal of experience so he would
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sketch the axle out and write down the
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specifications and then the drafting
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Department would convert them into
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drawings for manufacturing and
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purchasing Evan started working on this
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axle with Al Bosley at the start of 1957
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they talked a lot about what would be
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needed but they didn't have a whole lot
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of information about the car that the
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axle was being designed for the length
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of the pinion the vehicle track the
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amount of power or the amount of weight
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they only knew that it would be a light
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small car Al said that uh Evan had
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talked with the people who actually made
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the axles down in Lynch Road and they
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were not happy with the Hotchkiss axles
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used at the time and they included that
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the 7 and 1/4 in axle using a carrier
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tube was the way to go because it
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provided more flexibility on tread it
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was more rigid and it avoided
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manufacturing issues the axles that
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Chrysler traditionally used were
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two-piece drive axle arrangement with
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tapered outer end shafts that fit into a
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separate flange and had a nut and a key
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that held it together and they were very
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hard to get apart if you needed to get
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to the brakes or change axle shafts it
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was Al Bosley proposed using a flanged
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shaft like GM and Ford now at Chrysler
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since the very first Chrysler 1924 they
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always use straight axles with a taper
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and a bolt on flange instead of using a
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hot upset process where the end of a bar
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is heated and then forged back on itself
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to create a larger flange and the people
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at the axle plant said that it would be
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a little more expensive but they could
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still do it and it would be better
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overall for the car the drawings were
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released in mid1 1958 to the Lynch Road
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axle plant and to the purchasing and
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they just started designing the tooling
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they ordered the gear cutting machines
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got the casting patterns done and did
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everything else they needed now Al
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Bosley said that there were two things
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that he wishes that they had done better
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and the first thing is that neither of
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them ever thought anyone would run 300
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brake horsepower through that axle
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that's around 240 horsepower as we talk
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about it now and the differential gears
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in the pin were really too small on the
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Lighter Side the short grip versions did
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hold up better and the other thing that
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he wishes he had done differently was
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something that they did to save so in
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the 8 and 3/4 in shle that do talked
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about a couple of days ago the main
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drive gear pumps oil up to the front
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bearing along a passageway in the top of
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the actual casting there is a little
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void along the bottom of the rear
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bearing so the oil can get back again
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and they left that out on a 7 and a quar
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inch axle that was used on the original
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Valiant it turns out that both bearings
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didn't get enough lubrication so the
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axle ran a little hot Al Bosley later
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said perhaps if we had realized that
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someday we would want to put a 346 pack
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engine in front of it we might have
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thought about it a little bit longer in
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any case most of these things got
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changed later and he said that he
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thought that the waight and cost savings
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for the first 3 or 4 years was a good
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decision now you might be wondering
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about the small five bolt circle that's
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at the end of this axle at either end
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for the wheels to go on by the time that
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that was set up Al Bosley had joined the
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Valiant task force they made a choice to
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use a smaller bolt circle to make the
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axle shaft easier uh to process to make
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the upset process easier to create that
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flange and to save weight so the Valiant
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has a smaller bolt circle than the Chevy
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or Ford did but with five wheel bolts
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instead of four the Falcon and the
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Chevrolet had four wheel bolts on a
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larger Circle the wheelmaker said that
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that would be okay so they were able to
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cut the diameter on the flanged axle
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shaft I would like to thank Al Bosley
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for providing this information and he
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really did provide me with a good amount
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of material which I still haven't
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finished going through and presenting to
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you yet but hopefully I'll have more for
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you at some point soon I would like to
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thank Al Bosley who passed this story on
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to me when he was in his 90s and Peter
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dah who did the recent Mopar Axel
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presentation
#Autos & Vehicles
#Classic Vehicles
#Vehicle Modification & Tuning

