Have you looked thru the 1939 pictures and model info. Others here are much more knowledgeable in this area, but 1272 indicates a 1939 Super 8 Touring Sedan. If it is a 1939, the data book and owners manual as well as service manual are on site & should answer most of your questions.

And they said things were simple then. Looks like you'd almost need an owners manual to make sure the right combination of lights were on. What does the aux ignition do?

If I correctly decoded that chart you found but not able to download, BPR4ES decodes as
B 14mm
P Projected insulator
R Resistor
4 Heat range 4 from 2=hot to 11=cold
E Thread reach 19mm
S Standard 2.5mm center electrode

How much of the residual fluid would actually remain though? Assuming it was done on a routine basis, doubt it would have crystallized -- so with an inlet and the bleed screw usually above it, would think that the vast majority of the old would be flushed out--

I do see the benefit of removing drums though just to get a look at things and make sure the rubber or something mechanical hasn't fallen apart or hasn't sprung a leak not showing yet.

That is the valve for the optional vacuum antenna. The hoses would all route through a grommet on the front left upper firewall/cowl just below the patent plate--above where the wire loom and other items exit. My 47 has 3 short pipe sections molded in the grommet with hoses on either side. One goes to top, one to bottom of antenna and third to the carb area vacuum source. There should be some kind of port (maybe one capped off) near the base of carb or even intake manifold where the vacuum originates. If you do have the antenna and hook it up, the vacuum source goes to center port on valve, top of antenna to top port and then to lower the antenna, the bottom antenna hose to other one.

The metal tube in question is the heat tube which works the bimetal element in choke. Not really vacuum in true sense but rather a gentle vacuum pulls heated air from a stove in exhaust manifold into choke housing. You appear to have a different carb than I do but if it connects to a fitting on bottom of choke housing and to exhaust manifold where yours appears to, it looks to be OK. Mine comes from a hole on manifold in front of carb, a gentle bend parallels manifold a few inches and then 90's up to choke.

It's a 176K pdf file. If your email can handle that as an attachment, PM me an address and I can send it.

Spring composition is a good point. The spring from Reid is 302 stainless and I believe but can't say for sure the original is also stainless.

Quote: You might want to check out bulletin 56T-14https://www.packardinfo.com/xoops/html/downloads/STB/56T-14.pdf and compare those specs with the ones you gave the mechanic.

There was a mid year revision and slight changes to the curves from those in the original specs. Not sure right now where your spare distributor number fits, but the one on the car looks to be the original without the revision.

The closest spring I ever found was from Reid Supply, their item CX-14.http://www.reidsupply.com/Detail.aspx?itm=CX-14 While not exact with your dimensions, except for length so close I think it might work. Comparing with the original, if the free loops are the same (3) it might be able to stretch -- there is another with slightly larger diameter wire also a possibility.

Agreed, the spring is critical but I am not sure that is the entire problem. From the very few pictures of other units I've seen so far, Packard seems to be the only one who mounted low and at such an angle. Am not totally convinced that the angle doesn't have something to do with issue. To my mind it positions the valve port in the perfect location to have any debris or chunks of congealed fluid float right to it and lodge.

The small diameter has been brought up on occasion and there are threads here with some possibilities. Don't know if anyone has tried one but the theory is good. I think the bigger problem will be volume. With 4 large wheel cylinders having to move, shoe adjustment would be critical. I would be reluctant to depend on much reserve capacity out of a single small master since it again will be limited to a fairly short stroke. If it did turn out that the ratio issue wouldn't be a problem with the small bore, then wonder what would happen if there were a way to gang two small cylinders each feeding a pair of wheels.