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Here's an indirect indication that the bushings are a tight threaded fit in the control arms: The 444-544-210 chassis design dates from the 1940s and the designers at Volvo were veterans of designing the US auto industry. The Volvo front suspension allegedly emulated Plymouth's of the same era, which a look at Motor's Manual covering 1953 Plymouths tends to confirm. (US cars went to ball joints and press-in rubber upper bushes in the mid-50s, about when the Amazon appeared with some of those features.)
The Motor's Manual on installing upper arm bushes on pre-'57 Plymouths parallels Volvo's Service Manual, including use of a special fixture tool, and notes, as to the bushes, "Lubricate them with light engine oil or cutting oil to allow them to cut their own threads in the control arm without scoring. Thread the bushings onto the control arms until the shoulders of the bushings contact surface of control arm. Use a torque wrench to tighten bushings to [an impressive figure.]"
It seems important that the bushings in use not turn or wiggle in the control arms, but rotate easily on the pin that bolts to the crossmember. Endwise location of the pin is fixed by its threading into the bushings, so the initial positions of the bushings on the pin before they screw into the control arms matters.
The Volvo instruction doesn't reveal the purpose of the special fixture, but for the Plymouth, it is to spread the control arm ends 1/16 inch from the relaxed position, while the bushings are installed. I guess this leaves an axial preload on the pin threads to avoid play and clunking noise in use.
Hope this helps a little.
Charles Greenlaw, Sacramento CA
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