Bloo

Tighten 'er up. Looks like threaded sleeve. It's probably fine.

For starters, there is a recurring and confusing issue with the dash indicators on 53-54 Pontiacs, Chevrolets, and probably other GM cars. I highly recommend that you ignore those dash indicators entirely until the system is mostly working. If you have separate indicators on the dash for left and right, there is a good chance the 53-54 issue applies to your 51 car as well. I'll have more advice about that later if the dash indicators still malfucntion after you solve the main problem. What I would do: I would make a jumper wire with a couple of spade lugs, pull out the flasher, and jump 2 of the terminals on the flasher plug of the wire harness. Ignore the terminal that normally goes to flasher terminal "P", jump the other two terminals together. Now, if everything was working you would be able to turn on the signals solid (no flash). Turn a side on. Start by testing the front because the front is simpler and does not involve sharing a bulb filament with the brake lights. On the signal light on the side you turned on, try another bulb. Also check the bulb number. I suspect it should be 1154, but don't have a 1951 shop manual handy. If another bulb doesn't help, try grounding the socket shell. Attach a temporary jumper wire to any good ground. The (-) battery terminal is best, but any solid ground will do. Poke the other end to the outside (metal shell) of the bulb socket. 1) Does the bulb light? 2) If not, does grounding the shell of the socket make the bulb light? 3) If that made it light, which filament in the bulb lights when you ground the shell? It should be the biggest heaviest filament. Is it? Let us know what you find out. EDIT: Are these factory signal lights with a factory signal light switch? If it is an aftermarket switch on a car that was built without signal lights, that changes things slightly.

I don't know. On my 1936 208, I found paint marks indicating clocking. That implies that at least those 2 parts were probably balanced together, and that replacing the pressure plate would require re-balancing the flywheel at the very least. Worst case would be that Pontiac put the crank, balancer, flywheel, and pressure plate all in the balancer together, and you would have to have all those parts back out of the car. Ugh. I hope not. "External Balance" is not out of the question on a straight six, but it is highly unlikely in my opinion. Straight sixes are naturally in first order balance, and so it is just a question of balancing all the parts. There is typically no need for off center counterweights so large that they would not fit inside the engine, as sometimes occurs with V8s and other engine configurations. The 200s are old enough that balancing was not done by every manufacturer. I don't know exactly when Pontiac started. Even if the engine was in balance when it left the factory, the rods were still babbitted on the 200s, and it was common in those days to replace just one rod (or piston) from a parts store after some failure. You could easily have parts that no longer match in weight. There is normally no issue of "total weight" of a rod and piston assembly vs crank balancing on straight sixes. All that has to be done to pistons and rods is make sure the weights of all the piston and pin assemblies match, and the weights of all the rods match. For best results you would match and balance the big ends and the small ends of the rods separately. I would start by balancing the pressure plate and flywheel separately, and see if it helps. I'd have the balance shop check them together before starting to see if balance is likely to solve any problems, but then balance them separately.

The fuse only cares about amps. Just use a fuse with a voltage rating higher than the voltage of the system. A 32 volt fuse is fine on any 6 or 12 volt system. So is a 250v fuse. Just don't use something with a voltage rating too low. Don't use that 32 volt fuse on 120VAC house power. Most commonly 250v fuses are used on 120V appliances etc. The issue is all about actually disconnecting the circuit and stopping current flow when the fuse blows. When a fuse blows, a plasma cloud can form, plasma is much more conductive than air, and current might not disconnect, you are just left with an electrical arc where the fuse was. Since the whole purpose of the fuse was to shut the current down, this is bad. Also, things tend to blow apart. At 6 volts or 12 volts in a car, this is completely a non-issue, and you can use the cheesiest fuse you can find, though it might be hard to find anything cheesier than a 32 volt rated glass fuse. On 120V though, bad things could happen if you use an under-rated fuse. On 240V, there's a really good chance of something bad happening. On 480v, there is an extremely high probability of some sort of explosion if the fuse is not up to the task.

Checker

The Pontiac most likely has a "threaded sleeve" connection to the gauge on steel Bundy tubing. I don't believe there should be any rubber line under the dash at all. "Threaded sleeve" fittings are uncommon today, but available at Blackhawk Supply, and maybe a few other places online. I doubt you would find them at an auto parts store. Steel Bundy tubing in that size is completely extinct in the North America. If it needs replacing, and you are in the US, you'll have to use copper refrigeration tubing. It works fine. I think you'll have to get a look up under there. and see what it really has, and if someone has replaced it with inappropriate parts as @marcapra suggested. It is also possible that the bourdon tube inside the gauge has popped and the gauge itself leaks. You don't usually see that though. I wonder if the fitting is just loose? The Threaded sleeve nut becomes part of the tubing after the first tightening, just like a ferrule does in a plumbing fitting. The threaded sleeve nut once attached to the line is reusable practically forever unless damaged. You shouldn't need one unless you are replacing tubing, and in that case you definitely need a couple as they are not removable from tubing. They are sold by tubing size. Post pics of what you find, and we will try to help you figure it out. https://blackhawksupply.com/collections/plumbing-brass-fittings-double-compression Threaded sleeve nuts look like this:

Yes, people have done it. I've done it temporarily to get home decades ago, but never tried to get the capacitance spot on. There have been discussions on other forums by people who have. I believe I read over on Fordbarn Model A section about someone making Model A replacements with modern capacitors inside. I'd rather have 600V or more. I don't think 250V is enough. "Film and Foil" construction is far preferable to "Metalized Film", but that makes the capacitor physically larger. "Metalized Film" self-heals when it arcs over internally, but loses plate area every time it happens. Capacitance would probably go down over time. It might be OK at first, and transfer metal on the points later. Pay attention to temperature. It's hot in a distributor. Some kinds of film cannot take much heat (polypropylene etc.) while others can take more (mylar, polyester etc.). Anything even remotely close to the right capacitance with a high enough working voltage should run. I'm not sure what polycarbonate is in this context. I think I have heard of it but can't remember. If it's a film capacitor, ceramic, or anything else like that it should run. How close you need to be on capacitance to not burn points if you drive regularly I don't know. 0.22 is a standard value in electronics so is easy to buy. Tolerance for capacitance in Film Capacitors is typically rated +-5%, +-10% or +-20%. Whether 0.22 microfarads is close enough to not transfer metal on the points for your car, I have no idea. Try it and see. Don't use any polarized capacitor (with a dedicated positive or negative lead), so no electrolytic, or aluminum polymer, hybrid polymer, tantalum, or anything like that. Mind the decimal point (0.22). I've heard "22 microfarads" thrown about in other forums, and it most definitely isn't 22 microfarads.

I agree with all of that. They are high reliability parts, and there are applications where they perform better than film. By "not ideal" I was more thinking that they are further away from ideal capacitors than a lot of film capacitors, like for instance capacitance changes with applied voltage, and may drift quite a bit with temperature, etc. depending on what dielectric they are made with. That is splitting hairs for the mid 50s when they seem to have appeared. They were so much better the Paper Capacitors that came before it is hard to even draw a comparison. In their favor, as an ignition capacitor, high voltage ratings are readily available, as is C0G dielectric with almost no drift. C0G and high voltage makes for a huge disc though, but I am not sure if any of that matters. I suspect none of it does. Maybe the disc could be smaller. It's probably a little harder to package as a replacement than a film capacitor that is naturally the same cylindrical shape as a paper one and smaller.

No. There is no easy way to test one. Well, not outside of a dedicated and very old test fixture few of us own. The reasons why are complicated. This post will probably be long. Sorry about that. A traditional "condenser" for a car is a Paper Capacitor. Like anything, there are exceptions, but the little silver cans we are mostly talking about in this thread were traditionally Paper Capacitors. Paper Capacitors were used in radios too, and have a known unavoidable failure mode. Around 1929-1930, so I'm told, there was a tariff placed on the Japanese paper used in Paper Capacitors. At the time, these were huge capacitors used for power supply filtering in the recently popular radios designed for house power instead of batteries. The Japanese paper became expensive at about the same time as the depression was underway, and electrolytic capacitors, an unrelated technology, were introduced for use as power supply filters replacing paper. This made possible small cheap radios at a time when you probably couldn't really sell big expensive radios anymore. Small capacitors for the rest of the radio (not the power supply) needed to be inexpensive, and paper was the technology to do that, but the price of appropriate Japanese paper was through the roof. A US made substitute paper was found. Acid was used in the process. The acid remains in the paper and rots it over time. Every paper capacitor made from about 1930 on, and not just in the US, is destined to fail. The paper I am talking about is so thin you can see through it. It looks like plastic. A Paper Capacitor is just 2 pieces of foil with a piece of this thin clear paper in-between. The whole mess is rolled up in such a way that the pieces of foil do not touch. One lead hooks to one plate, and the other hooks to the other lead, or, in the case of an automotive condenser, the can. By the late 50s electronics had mostly abandoned Paper Capacitors due to reliability issues, replacing them first with ceramic capacitors, which are not perfect, and later "film" (plastic) of various types. "Film" is the default technology to replace Paper Capacitors today. Reliability is much higher. The last common Paper Capacitors in consumer electronics were mains filters in the 80s, intended to keep electrical noise on the power line contained. These "Rifa" capacitors are infamous for exploding and or catching on fire in recent years. Why? Because they are connected right to the power cord. Once they leak enough current between the plates.. BANG! Now this "leakage" between the plates sounds just like resistance doesn't it? As if there were a resistor connected in parallel with the capacitor? Why do we call it "leakage"? If it's resistance, why don't we just call it that and check it with an ohmmeter or ohms function of a DMM? The answer is because it is not constant. It is voltage dependent. The higher the voltage goes, the worse the leakage gets. As the voltage goes up, the resistance goes down. Pure resistance does not do that. Since ohmmeters and DMMs check resistance using a low voltage, like maybe 9 volts. A Paper Capacitor can check perfectly fine at 9 volts and still be really, really bad. An ohmmeter or DMM ohms function in no way tells you what happens at a few hundred volts. If a capacitor fails an ohmmeter test it is a bad capacitor for sure, but with Paper Capacitors, you will get mostly false positives with an ohmmeter or DMM. In electronics repair, if you are going to work on anything remotely old, and want to be able to test any capacitors you might run into, you need 3 kinds of capacitor testers. They are: 1) ESR meter. You have probably heard of these. ESR is effective series resistance. It is a controversial property that may or may not exist depending on who you ask. The tool itself is extremely useful for troubleshooting circuit boards full of small electrolytic capacitors, as it indicates the most common failure on those. It is not useful for automotive "condensers" at all, so that is all I am going to say about it. 2) A Digital Capacitance Meter or the capacitance function of a DMM. This will read the capacitance value of the capacitor, typically in microfarads or some other small portions of Farads. If these see leakage they usually just read too high. They may not see leakage at all because they are a low voltage device. These are useful to read actual capacitance, but only on a capacitor that you know is not leaky, and they cannot test for that. That's why you need... 3) A Capacitance Bridge. You probably can't buy this new. In the heyday of Paper Capacitors from the 1930s to the 1960s, these were in many radio/tv shops. These check for leakage at high voltage. The also check for capacitance with a method that is not fooled into reading high by leakage. Examples of top tier ones are the Sprague Tel-Ohmike TO-5, the Heathkit IT-28 and the Eico 950B. Prices are through the roof for these and a few other similar popular models, supply and demand you know, but Capacitance Bridges were made in a zillion brands and models from the late 30s through 1970 or so. There could be some bargains out there. They probably need restoration. These are the right tool for Paper Capacitors, because they test for the most common failure, leakage. You first test for leakage, which is typically read on a meter, possibly as resistance, possibly as current. Once you have established that the leakage is sufficiently low, you check capacitance by moving the dial and watching for a magic eye tube to close. When it does, you read the capacitance from the dial. If the Capacitance Bridge is out of calibration, and it well might be because it is over 40 years old, then you can check with a digital capacitance meter to get the exact capacitance value, having already checked for leakage with the Capacitance Bridge. Exact values may matter. If the capacitance is too far off, metal will transfer on the points from one side to the other, ruining them. So as you can see, you really need the last two testers to do any meaningful testing on automotive "condensers" aka capacitors. Additionally, you need to know the correct capacitance value for the car, and that may not be easy to find. A lot of cars use around 0.22 microfarads, but there is no guarantee of that and you might burn up a few sets of points figuring it out. New production "condensers" are most likely Film Capacitors, as that is the superior technology that has replaced paper. I don't think anyone makes Paper Capacitors anymore, at least not in volume. The fact that new "condensers" are not holding up, and are doing worse than decades old NOS Paper Capacitors that will definitely fail due to the acid in the paper illustrates just how bad current production ignition parts are. There are plenty of threads about it here on the forum. It should be nearly impossible for these new "condensers" to fail, and yet they do fail, and early.

I've rebuilt or repaired rather a lot of those old GM solenoids over the years, and 99% of the time the only thing needed is a copper bolt. If the mini starter is working for you, great. I do think they are a little bit more durable than the old GM starters, as the old GM starters usually needed a little attention sometime between 80K and 100K miles. As few miles as people drove back then, that's 8 years or so. It really isn't terrible. As little as people drive their antiques these days it is probably more like 80 years. The Japanese mini starters can sometimes go 200K miles or more, though I think 150K miles is more typical. Parts to do a whole starter rebuild are probably less than $60 even now, assuming no bad windings, for either a GM starter or a Japanese one. I'd be surprised if it is over $100. It was usually less than $20 in the 90s when I was last doing a lot of it. That was going to an auto electric shop to buy the parts, not an auto parts store. The auto parts stores really held you up on price on internal parts, and they weren't particularly good at sourcing them either. The copper bolt for the solenoid was about $2 then, and more often than not, it was the only thing wrong. Those bolts have probably gone up a disproportionate amount as copper is expensive now.

That wire from the breaker plate to the case really shouldn't burn unless it was already broken and only had only a strand or two left. I've seen a lot of them barely hanging on. Failure of the wire is a super common problem. It is the "ground" so all the current to charge the coil goes through it. It's a special wire on most cars, because every time the breaker plate moves with the vacuum advance, that wire bends. Like, every time you step on the throttle it bends. The wire needs to take that bending eleventy ziillion times without breaking. An ordinary copper wire could only take a few cycles. Most of the ones I have looked at closely are mixed extra fine strands of copper and spring steel. That all pretty much applies to the points wire too, or at least the part of it that is inside the distributor.

After spending way too much time down that rabbit hole several years ago, I think the answer is "no". I am going to say "no" and hope to be proven wrong by someone who knows more than I do. On second thought, I notice you said '24 and I may be answering the question wrong. Weren't there still Maxwells in '25? Either way, the rabbit hole questions I was referring to are "Was it possible to get hydraulic brakes on the very last Maxwells?" and "Was it possible to get 4 wheel brakes on the very last Maxwells?". Bigger Chryslers had hydraulic brakes. some of them and maybe all. In Canada rebranding of the 4 cyl Maxwell might not have been done at exactly the same time. Chrysler's engineers were making changes to the 4 cyl Maxwell/Chrysler/Plymouth at breakneck speed during that time. It seems like it should have been possible to get hydraulic brakes on the very last Maxwells, but I have never seen one.

Hose clamp remover. If you need it, you REALLY need it.

The shoebox Ford certainly is an iconic car, and one I like a lot. It certainly did break tradition at Ford, but technologically they were way behind. For me, it's pretty hard to think of it as revolutionary. V8, Hotchkiss drive, parallel springs, independent front suspension, etc. just sounds like they almost caught up to Oldsmobile, about a decade and a half after the fact. That and Kaiser-Frazer had slab sides in 1946.

I vote for automatic headlight dimmer.

Nothing matters as much as voltage at the bulbs. Well, that and the quality of the reflector, but in a sealed beam system there's nothing you can do about a marginal reflector except replace the bulb.

Additionally, you can rule out 1936-37 Buick 80/90, 1936 40, and any earlier Buicks because they are all older "spiral bevel" designs. This one in the pictures is a hypoid design.

Found the guy with vacuum wipers.

An older picture, but one I really like. 1936 Master Six Touring Sedan.

Clean or replace the negative battery cable. The spot that is getting hot has high resistance.

That's not a problem with the roundabout. In my view, if they are single lane, and follow the standard custom that the people in the roundabout always have the right of way, then roundabouts are easier. There is no question of who arrived when and who has the right of way. Traffic moves better too. Diverge from that custom though, and you can have an unbelievable mess. I've seen a few. Bardstown, KY and North Bend, WA come to mind.

It's inside the Pertronix, or something is. You just don't get to change it separately if it fails. A Pertronix grounds, or more accurately completes the circuit back to the spark plug threads, by being connected to the breaker plate in the same way the points and condenser were connected to the breaker plate. If there wasn't a something there like a capacitor to complete the circuit when the coil fires, thousands of volts would blow the poor little Pertronix to smithereens.

Capacitor and condenser are the same thing. Condenser is just an older word, like Mechanician. In the radio and electronics world, "condenser" was pretty much gone by 1934 or so, except for the one with movable plates used in radios, it was sometimes called a "tuning condenser" instead of a "tuning capacitor" as late as the mid 50s. In the electronics world it is well understood that the two are the same. Capacitors, or Condensers if you wish, come in many forms and with many different characteristics. Their value is called "capacitance" (technically not "capacity" though you hear that a lot), and is measured in Farads. Usually not whole Farads, because Farads are so big. Micorfarads (uF) and other small portions are more common.

Here is a grossly oversimplified version. The coil is an autotransformer, meaning it only has one winding, well sort of. The windings that take battery power are bigger wire, but then the winding just continues in smaller wire, a LOT of smaller wire and a lot of turns.That is why there is continuity between all 3 coil terminals. There is no DC isolation between a "primary" winding and a "secondary" winding like there would be in an normal transformer in a power supply for your stereo or computer etc. The end of all the smaller turns is connected to the coil wire. Important: There is no ground terminal on the autotransformer (coil), nor is it grounded to the housing. When the points close, the large wire part of the winding is powered by the battery. The iron core becomes an electromagnet. That electromagnet charges with magnetism, and hopefully it charges to complete saturation. It will if there is time. If the engine is not turning really fast, there is time. When the points open, the magnetic field in the iron core collapses, and it collapses suddenly, much faster than it can be charged with a car battery. This generates a voltage in the winding, the entire winding, both parts. This voltage is in the reverse direction, in other words positive and negative are reversed. If this were any ordinary transformer, you could know what voltage to expect by comparing how many turns of wire in the large wire (battery powered) part of the coil to how many turns are in the whole coil. In this case though, when the points open the magnetic field collapses faster than you can charge it. You get a LOT more voltage than expected across the whole coil. OOPS. There is no ground. More properly stated, there is no path back to complete the circuit. The electrical current must find it's way back to the other end of the coil winding to discharge this high voltage. But, we have opened the points, and that other end of the winding is not connected to anything now. It was connected to the block some microseconds ago, where the spark plugs are grounded, but we opened the points so now it isn't. The voltage rises to absurd levels in the coil. On one end of the winding, it must initiate a spark across the rotor gap and the spark plug gap. On the other end, the only path back is through the positive coil terminal, the ballast resistor, and the battery to get back to the engine block. This is a better path than you might think, as a battery has fairly low internal resistance, but the rise time of the coil voltage is extremely fast, and this path back through the battery is *extremely slow*. In no way can it get the job done, so the coil tries, and probably loses some energy there, but the voltage continues to rise extremely fast, and an unwanted spark initiates across the points to complete the circuit. Some people will tell you a capacitor (or condenser if you wish) passes AC current. That is not quite true, but in practice it APPEARS to be true. It can fake "passing" a pulse by absorbing a bunch of electrons. If we put a capacitor across the points, it completes the circuit, or at least appears to. It can't keep up the act for long, but it doesn't need to. It needs to react fast, and that it can do by collecting a bunch of electrons. Since it reacts fast, the coil does not to need to waste energy trying to get back through the battery, nor does it need to initiate an unwanted spark across the points. This leaves the capacitor charged, but when the points close, they short out the capacitor and discharge it. The capacitor is then ready to do it's job again the next time the points open. If the capacitor is not present, or open circuit, the spark will be extremely weak. More often than not the engine will appear to "have spark" but not run at all. The spark will be weak if it is present. The engine might actually run, but badly.

On older Chrysler products, there was a circuit breaker inside the headlight switch that would trip if there was too much current, then come back on, off, repeat, repeat. Any extra current could do it. The floor mounted dimmer switch @cudaman mentioned was a common spot for a short, as they would get wet, corrode, and leak current to ground. If it has a floor mounted dimmer switch, that is the first place I would look. If it's not the dimmer's fault, look for a pinched wire, oversize headlight bulbs, etc. Anything that would draw more current through the headlight switch than normal could cause it to kick out. I have no idea how a valet could have done it.