ElGecko, I want to disagree with you - look at the last picture posted.
If the cross-bolt in the lever is 1/4", it would be 7/16" across the flats. I reference that since it would be in the same plane as the shaft. Using my untrained eye, I am guessing the shaft is 3/8" dia, not 1/4"
I've read elsewhere it is common to use 1/4" threaded rod then cover the rod with 3/8" tubing. That would apply to the ones that run parallel to the cl of the car.
How 'bout it Kris. Can you throw a tape measure across some of the parts and solve this mystery?
Enquiring minds want to know
Thanks
Paul