HH56 wrote:
The book is entitled Auto Air Conditioning for Auto Mechanics by John Sensenig Jr. Published by Liaison Engineering Services and distributed by Remac Corporation of Dallas, Tx. I find no information on publish date but expect it is long out of print.

Here are a couple of photos of the 4 pages on the expansion valve. My scanner decided to be temperamental after the last software update so can't scan them. To make it worse, you probably will struggle to read the pages in the photos. If you can make them out the bit on why the externally sensed valve was needed with large evaporators is detailed fairly well on the third page next to the illustrations. The erratic action and flooding symptom was mentioned in another book's troubleshooting section on expansion valves and I don't remember where exactly that was.

As I said, maybe there was a limitation in the old valves or maybe R134a has different characteristics and that type valve won't be needed.