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Hi
Can anyone tell me why the left front wheel on a '36 senior car had a brake shoe lining narrower than the other three wheels?
Thanks

To compensate for the effect of the movement allowed by the trunnion block on the braking geometry. The narrower lining on the front left is particular to models with the trunnion hlock.

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Can you elaborate a bit on what a trunion block is and why it would cause this effect?

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That's probably the most counterintuitive answer I ever heard

I believe the trunnion block was part of a "kick shackle" arrangement designed to reduce road shock transmitted to the steering wheel when the front wheels hit a bump. It allowed the left front spring to move backward slightly when a bump was encountered.

For an illustration of the trunnion block see the lower left corner of this page from the 6th Series Mechanical Features brochure. The trunnion was discontinued on the Senior cars after 1936 with the adoption of independent front suspension and hydraulic brakes for the 15th Series.

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Interesting. What's the reason in particular for left front for this feature?

I think the left side location was due to the steering drag link being on that side. The device reduced road shock transmitted to the steering wheel and probably reduced bump steer in some situations. Some Dodge and Chrysler cars used a related device. The front suspensions on many 1960s cars had a lot of compliance built into them, and many cars used a "torque box" frame to add even more "give". This gave a very smooth ride at some cost in handling precision.