It sounds as though you already have the VW switch. Double check the contacts with all but the hot lead removed. If the contacts work properly then just hook up the wires acccordingly.

The original switch had one circuit with the common lead and normally closed going to TL and normally open to the brakes. When pressure applied the contacts reversed. The mechanical has 2 separate switches thus the need for pink wire to both ends. Since it is mounted with button pressed it is now "actuated" in normal operation so the logic is reversed with the normally closed to brakes and normally open to TL.

Thanks for the quick reply. ?, does the mech sw you used have 2 sets of contacts, 1 n/o and the other n/c. It looks like you have the 12v pink supplying power to both sets of contacts. I found Someone had wrapped the dk. green (stop light)around the 12v purple and the brake lights stayed on all of the time indicating the switch is defective or wrong type with no contact between those 2 terms on the switch. however the contacts on the switch do make and break for the LT grn. and the 12v pwr to the T/L. The switch is a replacement, Wells RB402. Apparently the OEM packard had 2 sets of contacts and the wells has only 1 (for the T/L). Ihe Packard shop manual or elect dwgs show the contacts and the parts manual doesn't mention it at all so I"m just guessing as to how the oem sw. worked. I'll try the local parts for the VW SW. you referenced.

Kev, Oops! This site has so much stuff on it I forgot that the manual is already here. I'll have to find another way to help.

I don't doubt that people have had failures of Treadle-Vac units, some perhaps due to incorrect rebuilds or other factors but my own experience over many years and miles is quite the opposite. Many years back I drove a 54 Patrician as an everyday car for 15 years and my current 56 for about 11 with no problems and although I know of folks who have had their units rebuilt for peace of mind, I don't personally know of anyone who has ever had a unit fail to the point of no brakes. Leaking brake fluid into the vacuum section, yes -- but outright failure - no. The same type unit was used on millions of GM and Ford products in that era, perhaps researching their service bulletins might be enlightening.

Well, Gentlemen, you have certainly convinced me that the Treadle-Vac has a potentially serious problem, far worse than any conventional single master cylinder problem such as on all of the non Treadle Vac Packards. There are undoubtably a large number of Packards on the road with Treadle ? Vacs or single cylinder master units.
Do we have a ?duty of care? to warn them?
I think not, because
1. Each Packard is equipped with an emergency cable brake on the rear brake shoes, the system should be in good operating condition.
2. Each Packard has a manual or auto gearbox in which a lower gear may be selected to assist in retardation.
3. Each Packard is equipped with an ignition switch which cuts the engine ignition.

I have had a number of complete brake failures, the most notable was in 1967 on the Sydney Harbour Bridge, in a 1939 Chev Master Deluxe, when I broke an axle which moved out and rendered me brakeless, gearless and speechless. The incident wrecked a good car and a potentially good relationship with my then girlfriend.
Notwithstanding that service records do not exist for over 50 year old vehicles, bad news travels via Service Bulletins, Jungle Telegraph and the Mechanic's grape vine. I have heard many stories about car's weaknesses but I have heard none about the treadle ?vac. I hope that mine continues to give good service in the 56. I am about to fit a remote power booster ( non treadle ?vac) to my 1938 Packard 120 and that may be another thread. Best regards and it has been a very interesting item, once again I am sorry that I unfairly involved Silicone brake fluid. Peter Toet

Jack, the spacer goes in there because the two pulleys won't bottom out together when assembled. Hence the spacer (I used a couple of washers to dial it in) to make it a solid unit. It's been in my Pat for over a year, at speeds over 90 miles an hour several times, with all the load from the supercharger on it, since I don't have the spring loaded idler like the Avanti originally had.

Straight eights are easier than the V8's, by far. All you need is an HEI unit off of a '70s Pontiac, and use the original lower shaft from the stock Packard distributor. You just drive the pin out of the Packard shaft to get the lower part off, then cut the Pontiac shaft to the appropriate length. You'll also need to turn down the lower housing on the Pontiac distributor, then have a sleeve machined to fit into the engine block of the Packard. I used the lower bushing on the discarded piece of lower Pontiac housing to connect the new sleeve to the Pontiac upper housing. The Pontiac is the best way to go, as it's already the correct rotation. If you have any questions, and I'm sure you do, feel free to ask.

"If there is a spacer between the two pulleys, then the outer portion is no longer an interference fit and thus is un-supported. Am concerned the sheet metal might eventually fatigue."

Then use a spacer of the correct thickness.
REGARDLESS, if metal fatigue would be an issue by not being supported then we really have a BIG PROBLEM with the water pump pulley. NO support there!!!!

"Cutting to the chase", has anyone documented a case where the compensator port spring has actually failed in operation? "

How much documentation exists (ever released to public or dealers) about ANYTHING failing prior to ca. 1965 ????
Witness the V8 oil pump. Relatively little documentation compared to the size of the problem as well as most of the documentation that is KNOWN to exist is questionable in relavence to the problem anyway.
It was FIFTY years ago. Not 10 years ago. It was a different world. A 30 day warranty. Not a 5 year warranty.

As for the steering head breaking on the 1907 Trump, i mean what do u want???? How much documentation exists for a 1907 ANYTHING ???? How much did they publish in 1907 anyway???? Probably very little.

One can not use 2007 expectations or analysis to explain something that is 50 to 100 years old.