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Hi all,

A friend of mine sent me this article which appeared in the Los Angeles Jaguar Club paper. It offers an explanation of the why and where-fore of Positive Ground and does so in such a positive way (sorry, I couldn't resist) that I thought I'd share it.

It says that their images are copyright protected but doesn't say anything about content so hopefully they won't mind.

lajagclub.com/the-argument-for-positive-ground/

Interesting. Don't remember hearing that reason before but as good as any. I thought plastic wiring happened a bit earlier than the 60s though since Packard used it in the early to mid 50s.

Perhaps "Mr. Lucas" wanted to be sure that plastic coated wire was not a "flash in the pan"? Hence the delay into the mid 60's. Sort of like Rolls-Royce and the mechanical combined with hydraulic brake system being used for the rear brakes through the Silver Cloud III. In defense of RR, their main concern with Disc vs Drum brakes was that disk brakes didn't always match their demand for silent operation until RR "perfected disc brakes" which allowed them to be used on the Silver Shadow. What a combined Mechanical/Hydraulic brake system would look like and how it would work is a mystery to me. The emergency brake was a third and separate system and all mechanical. All the RR material is according to Anthony Bird & Ian Hallows in their book "The Rolls-Royce Motor Car.

Perhaps "Mr. Lucas" wanted to be sure that plastic coated wire was not a "flash in the pan"?

Maybe -- but from what I remember and have witnessed first hand, Mr Lucas did not seem to worry much about such things. In many instances the writers comment about Mr Lucas letting the smoke out of wires if displeased was very appropriate. Doubt if he got the nickname "prince of darkness" because he only went out at night.

Didn't Hudson have a combo hydraulic/mechanical brake system too. I think the mechanical linkage was arranged so hydraulics worked all the time but if something happened so pedal wanted to go past a point to the floor the linkage became the active unit. Could be wrong but think Hudson linkage was also only to the rear wheels.

I've heard the corrosion theory before, but another explanation comes from "there is no such thing as negative earth" because the planet supposedly carries a positive charge.

Yet another comes in the form of the electron versus conventional theory of electricity in which conventional says current flows from positive to negative whereas electrons flow from negative to positive.

I have some other engineering papers around here that claim that exhaust flows are ionized and polarize the vehicle. This is similar to those anti-rust gadgets that attach to the vehicle's battery. I don't know if they work.

I have a chart that shows grounding by vehicle. Some brands - Chevy I think - were always negative ground. 6 volt Cadillac was positive ground except for 1937 only. I know where the chart is so if anyone needs to know I can find out.

The RR hydro-mechanical brakes used a mechanical servo powered by the transmission output shaft. Thus, so long and the vehicle was moving there would be boost. Great for a Treadle-Vac backup. Coupled to this was a mechanical override for the rears in case of hydraulic failure. The down side of this was that the vehicle had to be moving to have boost. Almost all of the Silver Clouds I dealt with had smashed up bumpers due to parking lot attendants in New York City. The cars would always lurch before boost and they would smash them up.