Bulkhead corrosion = charging issue

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fstfsh

fstfsh

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I've been grappling with a charging problem on my 1968 Barracuda notchback, 340 six-barrel. I thought it might be the voltage regulator, because testing showed it was not keeping up enough power. I replaced it. I eliminated the battery or alternator as the cause.

Now I believe the weak charging is a result of corrosion on bulkhead wire terminals. I am having difficulty removing the terminals from the bulkhead so I can replace them. I've use a needle nose pliers on the males. No use.. Suggestions?
 
use a small flat head screwdriver and shove it up the connector to press the little tab and then remove...
 
fstfsh said:
I've been grappling with a charging problem on my 1968 Barracuda notchback, 340 six-barrel. I thought it might be the voltage regulator, because testing showed it was not keeping up enough power. I replaced it. I eliminated the battery or alternator as the cause.

Now I believe the weak charging is a result of corrosion on bulkhead wire terminals. I am having difficulty removing the terminals from the bulkhead so I can replace them. I've use a needle nose pliers on the males. No use.. Suggestions?
Click to expand...

There has been hundreds of threads on this. No, I'm not kidding.

Here's an excellent starting place:

http://www.madelectrical.com/electricaltech/amp-gauges.shtml

Here's the simplified diagram on that page

amp-ga18.jpg



I take these problems as a "total package" but I divide the problem into sections

Generally this amounts to...........

1...Individual components, alternator, VR, battery

2...The output circuit of the alternator, or "charging line" that part going from the output stud, through the bulkhead, ammeter, back out the bulkhead, fuse link, to battery

3...The Field / VR part of the circuit. This is where the bulk of OVER charging comes from because you can have VOLTAGE DROP in the harness. The "path" and the main points of trouble are:

From battery, through fuse link..........through bulkhead (red wire)..........to and through ammeter..........welded splice..........back out bulkhead (black wire)........back to ammeter

The path to the VR is Battery........fuse link........through bulkhead (red)......to and through ammeter......(black)......through welded splice..........to ignition switch connector, through switch and back out switch connector.........(on blue IGN 1 wire)........back through bulkhead..........and feeding VR, ignition loads

THIS LAST above is very troublesome. You typically develop bad connections in all of those points, the bulkhead connector, the ignition switch connector or switch, and SOMEtimes the welded splice!!!!

What this does is create a VOLTAGE DROP which feeds lower voltage to the VR. The VR "thinks" the voltage is low and so cranks it up. It starts to maintain 14V at the VR sense point, but because of the drop, the battery now becomes HIGH -------by the amount of this drop



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To test for ignition harness voltage drop, get your meter "clipped" to as close as you can to the VR IGN terminal. This might be the ballast, the closest you can get. With the key in run but with engine stopped, find the highest voltage at the ballast. Now move your ground meter probe to the battery POSitive post, on low DC volts. You are hoping for a very low reading, the lower the better. If this reading is more than .3V (3/10 of one volt) you have troubles in the harness

================

The GROUND circuit can do the same thing but more rare. The VR MUST be grounded to the same potential (voltage) as the battery ground.

you can test the ground in a similar manner. Get the engine running fast idle, battery warm and "normalized." "Stab" one probe of your meter onto the metal flange of the VR. Be sure to stab through paint, etc. Stab the other probe onto the battery NEG post. As the test above, you are hoping for a very low reading, zero would be perfect. Make the test with all accessories off, and again with lights, heater, etc, turned on. As with above more than .2--.3V is too much.
 
My 72 Charger and the 75 Duster have both been guilty of this issue. I removed the terminal connectors for the main power and ground and drilled out the bulkhead connector and passed a section of 10gage wire through as mentioned in some of the other threads on this. You can leave enough wire for several cut and splice sessions or use new push connectors.
 
thanks, 67dart273. i have seen that diagram and did the checks. what i was saying is that i have narrowed it down to the bulkhead. and am having trouble disconnecting the male tabs from the bulkhead. i am not interested in modifying at this point, though. i just want to be able to drive with the headlights on! i think i am going to clean them first: vinegar and salt, and then a bath of baking soda and water. and then dry. thoughts?
 
Doubt it, at least for the two main charging terminals. If you don't want to modify, at least buy some terminals and replace them

I've said this before. "In a previous life" I worked at HVAC / R service. I've worked on a LOT of heat pumps, and "around here" the go to system includes a hot air electric furnace for an air handler and backup heat. Those use that same type 1/4" blade connector, and they fail a fair amount of the time.

A TYPICAL "standard" HEATING ELEMENT draws nominally 20A (5KW) off a 240V line, and they used to fail. Now imagine that same terminal carrying 40-60A from a larger alternator. It should have been no surprise to "Ma" that they fail, and, it turns out "it wasn't" (a surprise.)

If you look around for "fleet taxi" wiring, this is a modification of the wiring where the main alternator wires bypass the bulkhead. These were on some cars with optional 60-65A alternators

Inside an electric furnace controls box, these are about 20A circuits

melted-furnace-wire.jpg


hqdefault.jpg
 
fstfsh said:
thanks, 67dart273. i have seen that diagram and did the checks. what i was saying is that i have narrowed it down to the bulkhead. and am having trouble disconnecting the male tabs from the bulkhead. i am not interested in modifying at this point, though. i just want to be able to drive with the headlights on! i think i am going to clean them first: vinegar and salt, and then a bath of baking soda and water. and then dry. thoughts?
Click to expand...
It might or might not work. The corrosion can work down into the wires and the cleaning won't fix that. So look at the wire ends going into the terminals. And if you get a lot of that stuff into the wire ends, it may accelerate corrosion in the wires. I would only use sandpaper or other mechanical cleaning or burnishing. You might also consider some silver conductive grease to help out.
 
At one time I could actually hear my amp meter wire sizzling at the bulkhead connector. A couple of guys on here helped me through the "fleet bypass" to stop the pending meltdown!! Thanks Mark and Pete!!

Its not as involved as the MAD upgrade and makes me feel better about avoiding a fire!!!

At the same time I cleaned up all the connectors on the bulkhead with a file and sandpaper and filled them with dielectric grease. Like nm9stheham said, get yourself the Packard 56 connectors. The old ones should come out like KrazyKuda described, with a very small screwdriver.
 
To answer the OP's question, you release the male terminals by squeezing longitudinally at the base. It may help to remove the felt in the bottom of the connector housing. Search ebay for "56 terminal" or "Packard 56" or link in post #5. That will give photos and make it obvious. I use needle-nose w/ curved ends or some special little pliers I found that have rails on the tips that sit well on the terminals. Once you remove them, you can sand them to remove corrosion. Pack w/ silicone grease when you re-assemble. Pretty sure I posted photos years ago on my modernized wiring.

Re the infamous "melted bulkhead" problem. Mopar did have a solid design in 1963, using bus bars for the high current leads. They dropped it in 1964, brought back in 1965, then dropped in 1966 when they went to 3 connectors (wiper motor moved to engine bay). I put one from a 1965 Fury in my 1964 Valiant to get that feature, and that freed up 2 terminals for other things.

I 2nd post #8 on melted HVAC terminals. When my ~5 yr old AC compressor stopped working in Atlanta (AC/gas heat packaged unit), I went all thru the controls circuits and couldn't find anything wrong. Finally, I looked at the compressor itself and found a vaporized terminal. A little corrosion and things heat up fast. Apparently 5 cents of silicone grease would have hurt Carrier's bottom line. Fortunately, there was enough copper stub left coming out of the sealed compressor to solder to, which is what the factory should have done. Many cars have melted fuse-holders and such on the higher current circuits, like cabin blower.
 
thank you bill. your answer has helped much. i wonder whether i can install a '65 bulkhead in my '68. i also did a bit of poking around on the so-called fleet wiring. why can't i run the power line through the firewall with heavier gauge wire, fusible link and its own grommet?
 
fstfsh said:
i wonder whether i can install a '65 bulkhead in my '68. i also did a bit of poking around on the so-called fleet wiring. why can't i run the power line through the firewall with heavier gauge wire, fusible link and its own grommet?
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Nope. 1966+ moved the wiper to the engine bay, requiring a 3rd connector (wiper plus a few misc. functions).

You can run a wire thru the firewall, aka "fleet wiring". You can even find large stud feed-thrus (usually for trunk battery). But, do you need such high current in the cabin? The main high current is from alternator to battery. It was only run into the cabin to pass thru the ammeter. The "MAD Bypass" (search) keeps that path in the engine bay, but disables your ammeter. I designed a simple "diode shunt bypass" that keeps the ammeter active without going off-scale, but too techy for most here.

Some replace the ammeter with a cluster voltmeter (requires a bit of design work), or you can use a cigarette lighter voltmeter, or "fly blind on charging" like modern cars. The "factory indicator" when my 2002 T&C isn't charging is that the car goes bonkers when the voltage gets too low - windshield wipers actuate, tranny shows all gears lit, chimes go off, hence the cig lighter voltmeter.

Ideally, BATT+ is in direct series w/ the ammeter, so it shows net flow in/out of the battery. The factory did tap off a few transient circuits that don't go thru the ammeter (spot-light, convertible motor, engine bay loads - horn, starter, Vreg). I like my ammeter functional, but all manufacturers dropped them due to cost and since most drivers were clueless about electricity anyway (my dad learned from his neighbor who learned the mis-information from his grandad, ...).
 
thanks bill. that is good information. i guess i am confused, though: i simply want to make a connection that does not melt again. so i thought that i could isolate the power wire from the plastic bulkhead. this would not change how the ammeter works, though. would it?
 
I've moved those wires off the bulkhead on a couple of cars, after the resistance caused those ports in the bulkhead connector to melt. And it won't cause a problem or issues with the way the ammeter works. I don't know why a lot of guys do away with the ammeter as the needle is only driven by the movement of juice through the brass strip that those two heavy red and black wires connect to on the ammeter gauge. Sometimes there are open ports in the bulkhead connectors you can move the alt and battery wires to; other times I've drilled new holes in the firewall and used grommets, sort of like what the factory did on police and taxi applications. If you keep the connectors clean and greased up you should have no further problems, unless you upgrade the alternator to one putting out more amps - then I would definitely bypass the bulkhead.
 
I'll 3rd "yes", the "fleet wiring" (search). If you keep the ammeter, clean the pads well and insure tight. Any resistance there can melt the dash circuit board. If you go to a higher output alternator, you would peg the ammeter. Might not damage it, but could melt the wire to it (14 awg?). I use a large diode to shunt high current thru the engine bay as current increases. Search "Modernized Engine Wiring".
 
I redid the wiring on mine per the MAD mod and the advice of 67Dart273. Really not that bad of a swap and the end result is a much better than factory setup. To get the male terminals out I just insert a 90 degree pick and bent the tab back then they pull right out of the bulkhead once you take the tape off the inside loom. Clearly if they have melted in there you will have a bigger issue...

It is worth the time and effort to remove the packard terminals and drill the hole for your primary red wire with a #2 drill to pass a solid 10 gauge wire through. If yours is an issue on the headlights you may be chasing additonal terminals. The over / undercharging issue is a result of a voltage drop as 67Dart273 explains in his many posts.
 
airgrabber said:
I don't know why a lot of guys do away with the ammeter as the needle is only driven by the movement of juice through the brass strip that those two heavy red and black wires connect to on the ammeter gauge. .
Click to expand...

There ARE problems with ammeters

Firstly, many of these cars, the studs are not soldered, brazed or even really, riveted to the brass shunt. Bad connections right there can cause problems

If you look on the MAD page, there's a photo of what appears to be a melted PICKUP ammeter. These later clusters were plastic backed!!! and the ammeter studs!!!! went right through this thermoplastic structure!!! and depended!!! on the plastic!!!! to keep the connections on the studs tight!!!!

!!!!OMFG!!!! Before Al Gore invented the internet, LMAO, "up here" we used to have quite a few guys with melted ammeters in pickups WITH SNOW PLOW lifts or winches.

I helped fix a few. In a few cases, the owner opted to install an aftermarket ammeter, and just wire it in. In a couple of cases we bypassed the ammeter, and installed an aftermarket voltmeter, and in yet a couple more, the owner opted to just bypass the ammeter and "do without" LMAO

"I can tell if it's charging, the lights get dim, LOL"

So to sum up the actual ammeter problems per se varies with year / model. Basically, poor connections at the studs, poor connections with the brass shunt, and on some years, a plastic cluster
 
I might be the only owner who believes the OEM engineers did a fine job of keeping melting and fires outside the cabin and away from the occupants. If they hadn't had this goal we would likely find lesser terminals ( like push on ) at the amp gauge.
If there is a fault ( or more likely a combination of faults ) that caused overheating in electrical, relocating the point of meltdown wouldn't be the best plan.
 
not sure on your's, but later cars (my 74' dart for example), have a second wiring harness plug near the back of the engine. another place for a bad connection...



good luck RedFish, I think SlantSixDan has even given up trying to educate those uninterested in doing it right...

yes, ammeters go bad, so do starters, alternators and water pumps. every time an ammeter does I should complain it only lasted 40+ years and the design sucks?
 
kursplat said:
not sure on your's, but later cars (my 74' dart for example), have a second wiring harness plug near the back of the engine. another place for a bad connection...



good luck RedFish, I think SlantSixDan has even given up trying to educate those uninterested in doing it right...

yes, ammeters go bad, so do starters, alternators and water pumps. every time an ammeter does I should complain it only lasted 40+ years and the design sucks?
Click to expand...

Maybe because some of us has seen it different? Those pickup trucks I mentioned didn't last any 40 years..........and as I've mentioned countless times, Ma even knew "her design sucked" because there exists fleet / taxi wiring. So I'll just say this again. If this design is so "solid" why did "we" need "fleet" wiring? AND to top off the argument, the Sea Barges went with remote ammeters sometime along a bout 71? 72? along with Ferd and GM about that time.
 
67Dart273 said:
Maybe because some of us has seen it different? Those pickup trucks I mentioned didn't last any 40 years..........and as I've mentioned countless times, Ma even knew "her design sucked" because there exists fleet / taxi wiring. So I'll just say this again. If this design is so "solid" why did "we" need "fleet" wiring? AND to top off the argument, the Sea Barges went with remote ammeters sometime along a bout 71? 72? along with Ferd and GM about that time.
Click to expand...


that was easy.... :)
 
I trust a solid wire a whole lot more than a spade connector.:violent1:
 
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