unclepunchy
Well-Known Member
Wait, am I crazy, those terminals look the same as the one in my hand, no? What is the difference?
Fried Blue Fld wire from Alternator
- Thread starter unclepunchy
- Start date
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I would take it right back to the store, and take your multimeter with you. Check the replacement. This is a well known problem on isolated field alternators, AKA either the rebuilder was sloppy and broke or left out the insulators for the brushes, OR THE FIELD itself has a sort to the rotor body. OR they do so on purpose, attempting to sell later units to fit the early applications. This is a dangerous strategy as you just found out.
I WOULD NOT USE a single wire regulator under any conditions. The 70/ later "flat" regulator is far superior.
The blue wire is (obviously) NOT fused, and is simple. It goes back and branches into the "run" circuit coming out of the bulkhead connector, which feeds, depending on year/ model, the ignition ballast, blue field, VR blue IGN terminal, electric choke if used, and a few other doo dads depending.
I WOULD NOT USE a single wire regulator under any conditions. The 70/ later "flat" regulator is far superior.
The blue wire is (obviously) NOT fused, and is simple. It goes back and branches into the "run" circuit coming out of the bulkhead connector, which feeds, depending on year/ model, the ignition ballast, blue field, VR blue IGN terminal, electric choke if used, and a few other doo dads depending.
Missing or broken hardware, or the field itself has an internal short
Hmmm.......Maybe the assembler put the insulating washer between the holder and the alt frame, when it should have been between the mounting screw head and the terminal?? Not sure what to say??
The part number says it is setup for single field wire. Nothing wrong with the alternator
There are subtle difrences.
- The insulated version has a larger diameter hole in the terminal (red).
- The top of the plastic has a built in ring to insulate the terminal from the screw (like this green arrow for the location and the green circle for what it looks like
.
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Would not matter the hole on the terminal is just large enough for the screw. As best I can tell from the photo.
Plus the working end of the terminal is short, normally they are too short to have a connector put on it.
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Who or how was this part number determined
It appears that this company simply moved the black isolation washer from under the screw&lock washer and put it under the holder body, thus grounding that terminal, a quick & easy "conversion". Had You attached the green & blue wires in reverse, the alternator would've full-fielded, & charged 18-19volts boiling the battery.
Move the black isolation washer to under the screw&washer & re-ohm it. BOTH terminals should have read infinity, but the isolated terminal was reading the rotor windings to ground, and of course the other was providing the ground thru' the screw.
Peace..
Mattax
Just the facts, ma'am
Cheat sheet: First picture in post #15 shows the insulators and brushes for isolated field roundback and 1st gen squareback.
Alternator repair, a little show and tell.
Those replacement parts came from this mail order store
CHRYSLER ALTERNATOR PARTS (early)
Premium quality alternators, alternator parts & alternator repair kits forearly chrysler alternators at wholesale.
www.aspwholesale.com
Mattax
Just the facts, ma'am
Assuming its the correct pulley and rotor, simplest route is to buy a new brush insulator and insulating washers.
or if the parts store selected the alternator for you, then you could have them get you a correct one. Whatever is easier for you.
Blue wires.
Look at how they are connect for '73.
Follow the wire segments back from the alternator field terminal that was grounded. Go all the way to the key switch if neccessary. With any luck the segment from the welded splice to the alternator was smaller gage than the wires further back.
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So start with wire J2 F at the alternator connection and work back to connector CE37.
That might be the Engine harness connector.
Then from that to the welded splice. Hopefully the J2C going back to the bulkhead connector is not damged because its 16 gage. I would check at the bulkhead connector too. Remove the terminal from cavity N and check it out visually.
Then pop its mate out and go under the dash and check it out.
And finally to be sure. check the J2 wire terminals in the column connector.
or if the parts store selected the alternator for you, then you could have them get you a correct one. Whatever is easier for you.
Blue wires.
Look at how they are connect for '73.
Follow the wire segments back from the alternator field terminal that was grounded. Go all the way to the key switch if neccessary. With any luck the segment from the welded splice to the alternator was smaller gage than the wires further back.
edit
So start with wire J2 F at the alternator connection and work back to connector CE37.
That might be the Engine harness connector.
Then from that to the welded splice. Hopefully the J2C going back to the bulkhead connector is not damged because its 16 gage. I would check at the bulkhead connector too. Remove the terminal from cavity N and check it out visually.
Then pop its mate out and go under the dash and check it out.
And finally to be sure. check the J2 wire terminals in the column connector.
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EXACTLY!
red circle is the insulating post
blue circle is the larger hole that fits AROUND the insulating Post
Green circle is the FULL terminal end
OPs photo...
red arrow is where the insulating post MIGHT be (we have not seen a photo yet)
blue circle MIGHT be a larger hole (LOOKS Small in the photo) that fits AROUND the insulating Post
Green circle is the cut off terminal end
IF and ONLY IF the Blue and Red are as in the upper photo you might be able to move the black washer to just under the bolt head BUT it might need to be where it is also as a spacer SEE THE LAST PHOTOS. BUT with the shorter terminal you stand a good chance of the connector touching the bolt head and shorting out.
SAVE yourself a headache and replace the brush, holder, screw and washers with a new correct ones.
I dug out a recently rebuilt ( in this case it is a revised square back).
It's application is 67 Dart. It should have been a round back with only 1 field terminal but the cores are hard to come by so the rebuilders make a modification to a square back.
Note no insulating washer under the screw head. Screw head touches the terminal and the case of the alt GROUNDING that terminal.
Note the terminal is cut off and too short to fit a connector
Note the insulating ring has been broken off red arrow.
You MUST have the insulating ring or the terminal WILL move and short the terminal to ground.
As for the fiber washer UNDER the plastic insulator. I suspect it is a spacer
With out fiber washer under plastic insulator. (Note: you can not see the brush)
With fiber washer under plastic insulator (Note: you can just see the brush)
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I'd say Dana's correct, that's a grounding style holder, going back to the 1st pics. There would be the same terminal retention hole in the tab as the other brush if it were meant to have one attached , and the holder body is narrow, so even tho' We can't see the insulating ring's presence I'd say it's not there. Get the '73 brush kit... it's really poor form to manufacture a dedicated grounding brush with a tab large enough to actually attach a terminal to, what could go wrong there???...oh, YOU found out, glad Your car didn't catch fire.
Peace.
you said a mouth full there.
all the recent 1 field wire Squareback alternators had the 2nd (now grounded) field terminal OVIOUSLY cut (not enough in my opinion)
they should be cut off flush with the insulator
REQUIRED watching
69 and older
70 and newer
69 and older
70 and newer
unclepunchy
Well-Known Member
Ya, looks like the part of the post broke off. Here is a shot if both terminals.
Disagree. The customer cannot know what the part number means. The second terminal should have been REMOVED or modified to prevent this very problem
EDIT. Look carefully at the top brush. The screw appears that it will contact the electrical tab directly. There needs to be an insulator UNDER the screw head and on top of th electrical terminal, AND that insulator MUST have a shoulder to center the screw inside the terminal to keep it from contacting.
You have to use your head on these because many are aftermarket, and ARE NOT MADE exactly like OEM "was"
The last time I needed a set of isolated brush/ holders, I bought them from NAPA and they were wrong/ boxed wrong. I ended up with THREE boxes of brushes from them, all same part number, and mixed and matched pieced to make one useable brush set, then turn two of them back to NAPA for "defective or mis boxed." To this day I do not understand it. I sold auto parts decades ago, for over 15 years
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Customer better start knowing what parts he / she is ordering.
I agree, the reman guys need to do a better job of removing the extra terminal, BUT there is still nothing wrong with the alternator for the cars it is specked for. I could bolt it into my 67 Dart and I would have only one field wire to attach to the one un modified field terminal
we have gone over that already several times.
Yep new holder and maybe another insulator washer for under the head of the bolt
brush holder
39-3201 - Brush Holder
insulator washer
WASHERS - Alternator & Starter Parts Wholesale
round or square back brush
38-301 - Brush
Revised Square back Brush
38-303 - Brush
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Where did you buy the alternator?
who and how was the part number chosen?
who and how was the part number chosen?
Mattax
Just the facts, ma'am
That horizontal brush holder is for a revised squareback.
I wouldn't use that if I could help it for reasons posted in the '69 replacement thread and elsewhere.
unclepunchy
Well-Known Member
It's totally my bad here guys. I ordered this for a 69 instead of a 73. I had no idea about 1 and 2 fields/terminals but now I do with your help. I will order new brushes or just get a 73 alternator, they are not that expensive.
I am also going to take the advice of going back through the blue wire/bulkhead etc and make sure everything else is in good order.
I am also going to take the advice of going back through the blue wire/bulkhead etc and make sure everything else is in good order.
what if the alt is a revised? we still have never seen the entire alternator?
in a nut shell what's the issue with that holder? (just curious and too lazy to look it up)
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