ply33

That looks like a different approach to the problem than Mr. Peterson took. Peterson’s regulator fit inside the generator and replaced the third brush for powering the field coils. Nice smooth operation and you use the original cutout or, by cutting a jumper to change the voltage set point, a cutout that has a diode replacing the original contacts. The one linked to looks like it is a replacement cutout that toggles the output on and off based on the system voltage. I guess it would work but the videos show it switching between discharge and charge periodically which would bother me. And I wonder how high the no-current voltage generation inside the generator might get. I am not an expert but I’d want some assurance that the insulation on the armature and field coils, etc. can stand up to that abuse. If @AB-Buff can successfully reverse engineer Peterson’s design I think will will be a nicer solution.

I don't think the 3rd brush setup was a much of a problem back in the day as you were driving the car daily on a pretty regular schedule, say to & from work, so the charging requirements were much the same from day to day and only needed adjusting with the seasons (colder & more headlight use in winter needed a different setting that summer, etc.). But for a collector car that is not doing the same drive every day the situation is different. If you are planning on driving the vehicle a lot in a mix of local and road trips, that hidden electronic voltage regulator that Peterson made is a really great change. For short local trips you want a fairly high charge rate to replenish the charge lost when cranking. For road trips you want a much lower charge rate. Except at night when you want a higher output. With a straight 3rd brush setup for current regulation you end up having to adjust it all the time and/or play with the headlights to keep the battery charging about right. With that regulator you just get in and drive. Assuming he is still around making them, I highly recommend getting one. It is one of the two modifications away from stock on my old car, completely reversible, that I am really glad I did it about 20 or 25 years ago. The other modification from stock for me is getting quartz-halogen bulbs for my headlights, again totally reversible. I'd do LED headlight “bulbs” but I am not aware of any that properly focus in my bulb & reflector style headlight.

This may be totally off the wall, but there are voltage converters made for golf carts that can take anything from 12v up 48v on the input and give you regulated 12v out. They are used to provide 12v power for lights and other things on the cart that use regular automotive voltages. A quick search turns up this one: https://www.amazon.com/Cllena-Automatic-Converter-Regulator-Waterproof/dp/B08KZS81Y1 (I have no opinion on how good this one is or if there are better ones available). If you can find 12v bulbs that will work in your headlights then maybe one of these converters could then be used to power them.

Parts book only shows front and rear and indicated two each are needed per car, so the left & right are the same.

Chrysler part 657449 is the front brake backing plate for Plymouth passenger cars from 1936 through 1942. Plymouth commercial cars (trucks) used a different part. I don't have a Dodge parts book but it would not surprise me if they were the same. edit: PS, the 1936-48 Plymouth parts book calls them “Wheel Brake Support and Adjusting PIN Assembly”. Backing plate is definitely less of a mouthful.

Not sure about the PJ, but new shoes are not available for the earlier PC, PD, PE & PF. A brake and friction shop, the place local garages send stuff to be rebuilt, to get them rebuilt will be your best bet for relining the shoes. There are Internet and mail order places that can do that too, but I prefer to work with people I can talk to over the counter. The hoses and cylinder rubber parts should be still available. Most you can get from your local auto supply but the usual vintage Mopar suppliers can help if your local shops require things to be in their computer. I don't have a '35 PJ parts book so that is a bit of a hole in my cross reference database but if the part is the same for '34 and '36 it is likely to good for '35. My cross reference data is available at https://www.ply33.com/Parts/numeric and might help you find modern numbers for your old parts. You will not get good brake performance unless the curvature of the shoes matches the curvature of the drums. In the old days repair shops had brake shoe arcing equipment to do this. With the hazard of dust from that operation and the advent of disc brakes that day is long gone. I found I could get a pretty good job done by using a roll of sticky backed sandpaper. Stick some around the inside of a drum then rub the shoes that will be used with that drum unit there is smooth continuous contact. Important: Each shoe needs to be arced or fitted to the drum it will be used in, especially if the drums have been turned. With new or relined shoes you will need to do a "major adjustment". The best way to do that is with some specialized tools. The original factory tools were from Miller and those seem to be very rare. AAMCO made a different tool that can still be found but the prices are now astronomical. If you are not trying to make money on shop rates (i.e. doing it yourself and time is no problem) you can get close using an iterative procedure as written up at https://www.ply33.com/Repair/brakes edit: p.s. I found that a home made pressure bleeder makes a big difference in getting the brakes bled properly. I've done it with the two person operation but that is slower. Some people have luck with the vacuum bleeder kits but I have not had as much luck with those. p.p.s. Getting a factory service manual will be a big help. I don't have one for '35 but they should be available. If not the 1936-42 factory service manual should be available and the cars are mechanically very similar so it should be okay to use that.

I have a cousin who, at least years ago, was very good at getting the driver behind to dim their lights using that technique. I was never able to get the aim right to use that technique.

Are you, like me, waiting for the US rules to change so we can get adaptive driving beam (ADB) headlights?

While there are things beyond our current comprehension, a solar eclipse isn't one. The first successful prediction of one in written history is over 2000 years old. For much of the time since then those who studied these things could state when one would occur but not exactly where. Since Newton figured out classical rules for gravitation, the predictions started getting better and better with regards to exactly where especially now that the heavy number crunching is done with computers..

In that era Plymouth used right hand threaded wheel hub bolts (as the parts book called lug bolts) on all wheels, original Chrysler part number 393984. The left hand threaded fasteners were used on some earlier cars and then again later starting in 1940. That Chrysler part 393984 is still available: Check out Napa 6411554 or Dorman 610-018 Your best bet for the wiper motor(s) would be to have them rebuilt.

Is James Peterson still around and making these? If so that is great news. For what it is worth, I installed one of his electronic voltage regulators in my '33 Plymouth nearly 25 years ago and it is still working perfectly. Totally hidden and the modification is totally reversible if you decide to go back to stock 3rd brush operation. It makes the charging system work just like that of a car from the later era equipped with electronic regulators. You still have to mind the maximum output of the generator but if you are otherwise stock that is not an issue.

Chrysler seems to have moved the location on the frame from time to time and maybe from make to make. On my '33 Plymouth the engine number is stamped between the running board supports on the driver side.

This may, or may not help: https://www.ply33.com/Repair/tempgauge There are also professional repair shops that can do the job. Or do you need the entire assembly including the dash unit?

Back of the napkin math: In an early post you showed the diameter to be 11 inches. Assuming the flange around the outside is 1/2 inch, you have 10 inches of working diameter or 78.6 square inches of area. Assume you apply 15” of vacuum or around 7.3 psi. That pressure differential will result in about 575 pounds of force on the rod. I am not surprised you couldn’t hold it back with both hands.

505 is a plausible trim code for Plymouths in the 1930s. Unfortunately, I have never seen a list of paint and trim codes for the 1933 Plymouths so I can't say for sure.