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EFV-8 Club Forum / General Ford Discussion / 12 volt system

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Posted By Discussion Topic: 12 volt system -- page: 1 2     Ramblin Reck 07-14-2021 @ 5:01 AM reply profile send p.m. Member Posts: 9 Joined: Jun 2021 I am new to the forum. I am now the proud owner of a 1939 Ford Deluxe Vert with Rumble Seat. It runs but doesn't stop well so I am replacing all of the brake system from the master cylinder to the wheel cylinders. Parts are on the way. If that doesn't fix it, I will look then at the shoes and drums. But my question is about the electrical system on my Pride and Joy. I used a volt meter to see what voltage the battery reads and it says 12 Volts. So I assume that all operating systems that use electrical current are 12 volt: ie the starter, alternator, lights, windshield wiper, etc. Hope I am correct in that assumption. I was told that the flat head engine in my car is not the original but a 1946 or 1947 engine. Could that account for the change to a 12 volt system? I was under the assumption that the original 1939 Ford was a six volt system. I guess you could say I was mildly shocked (pun intended) when I saw the positive terminal lead bolted to the fire wall! My first experience with Henry's take on electrical matters. ******I learned from the original long term owner of this vehicle that he did change from 6 volt to 12 volt. Now we move on to the braking system. Thanks for everyone's help and advice. I have learned some important information in my first week of being an Early V8 owner. ******* This message was edited by Ramblin Reck on 7-17-21 @ 7:16 AM Kens 36 07-14-2021 @ 7:08 AM reply profile send p.m. Member Posts: 352 Joined: Oct 2009 Congratulations on your "new" car and welcome to the forum! Starting with the brakes is not a bad idea. Properly set up, the original braking system should stop your car just fine. All Early Ford V-8's were 6-volt, positive ground. This continued through 1955, so a prior owner of your car must have had a reason to change. Once you get your car to stop, going through the entire electrical system is a good next step. Be especially aware of the condition of the wiring. Good luck! Ken trjford8 07-14-2021 @ 7:39 AM reply profile send p.m. Senior Posts: 4232 Joined: Oct 2009 Many people go to the 12 volt system due to failing to bring the 6 volt system up to stock standards. Failure to use the proper size battery cables and properly grounding the system causes most of the problems. Next is making sure the charging system is up to the job of keeping the battery in good shape. Definitely fix the brakes first and then move to the electrical. I might also suggest that you purchase the V-8 Club's 38-39 book as it will help you with facts and figures of your new purchase. In addition join the Early Ford V-8 Club if you haven't already. The bi-monthly magazine, the V-8 Times, is well worth the price of admission. You also get a roster of members, some of who may live near you and can give you some great advice. Welcome to the forum therunwaybehind 07-14-2021 @ 11:12 AM reply profile send p.m. New Member Posts: 180 Joined: May 2019 The generator output on this system needs to be about 13.2 volts to charge the battery where each cell voltage at full charge is 2.2 volts. The cell resistance in discharge takes that down more and more as the battery ages. The reason why the different views of ground is that electrons that flow in the wires were discovered to have a negative charge and the ions in the sulphuric acid that migrate between the plates have positive charges. CharlieStephens 07-14-2021 @ 11:46 AM reply profile send p.m. Senior Posts: 894 Joined: Oct 2009 Now is the time to look at the shoes and drums when everything is apart. If the shoes have oil or grease on them replace them. Be sure to have the new ones arced to match the drums. Call the local chapter of the club and see who does it in your area, only a few shops do it anymore but it is an important step. If the drums have grooves in them have them turned. Have them measured. If they are over 12.060 replace them. If the car has has been together and running for a while you are probably ok with the electrical. If it just went together and has never been run you might have some knowledgeable on the electrical look at it. It is amazing how bad some of the conversions are. The one thing that scares me, although it will work, is the fact that it is positive ground. Most good electrical people go to negative so modern electronics can be used in the car. Ford went to 12 volts in the mid sixties so the engine change didn't drive the change. Welcome to the forum and how about posting some pictures? Charlie Stephens woodiewagon46 07-14-2021 @ 12:33 PM reply profile send p.m. Senior Posts: 705 Joined: Nov 2012 Forgive me for questioning you, but why wouldn't you check the shoes and drum's first? You are replacing everything but the two things that are designed to wear out and easily serviced. 42wagon 07-14-2021 @ 2:01 PM reply profile send p.m. Senior Posts: 586 Joined: Oct 2009 I'm not sure what you mean by "the car doesn't stop well". Don't expect that car to stop the way a modern car with power brakes does. I hope you aren't disappointed after doing all that work. As for the electrical system you should be able to tell whether the battery is 6 volt or 12 volt. 12 volt systems are negative ground. Not sure what happens if you hook it up backwards. And I also wonder what the other major electrical components are. JayChicago 07-14-2021 @ 2:19 PM reply profile send p.m. Member Posts: 492 Joined: Jan 2016 Another thought for what its worth: You have an unusual 12 volt positive ground. Usually (but not always) when an old car is converted to 12 volt it is also converted to the modern standard of negative ground. Do you know the seller, and the recent history of the car? Could it still be a 6 volt system? Could someone have put a handy 12 volt battery in there to complete the sale / get the car gone? I agree with the advice above that you should join your local chapter of the club, and get some experienced guys to help you figure out what you have, and where you need to start working. sarahcecelia 07-14-2021 @ 6:08 PM reply profile send p.m. Senior Posts: 1194 Joined: Mar 2013 I did many brake jobs" back in the day" and that is an "Old Wives Tale" and a "money maker," that brake shoes that have grease or brake fluid on them need to be replaced. I just washed them with gasoline, sanded any glaze on them off , and they worked like new! I did it on customers cars at the dealership that I worked for, and never got a "Come back!" The grease or brake fluid won't penetrate those hard linings, it's only on the surface! Regards, Steve Lee Ramblin Reck 07-15-2021 @ 6:52 AM reply profile send p.m. Member Posts: 9 Joined: Jun 2021 The master cylinder is easy to get to and I have a younger friend who knows how to bleed brakes. We filled the master cylinder and he opened the bleed screw on the starboard rear wheel while I pumped the brakes. Not necessary to jack up the car. Nothing came out of the bleed screw so we assume that the lines have collapsed from extremely long periods of sitting idle in a garage somewhere. The car will stop so we must be getting brake fluid to the front wheels. The brakes are real squishy if that 's a word. The fluid in the master cylinder was dark and there were pieces of matter (looked like cork?) floating up in the master cylinder. So there you have my deductive reasoning. No need to apologize. The only dumb question is the one that is not asked. Thanks to everyone who replied to my post. I really do appreciate it and need all the help I can get. I have paid my dues to the Early V8 club and look forward to my new hobby. And I will get some pictures posted.

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