walkinfool

Bad crimps

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A few months back I wrote to ask for help diagnosing an intermittent charging issue. Several faq’ers wrote with great suggestions and though the immediate problem was a bad ground that was easily fixed, my alternator eventually gave up the ghost. Rather than go the rebuild route, I decided to buy a locally sourced reman’d unit from Bosch for just a few bucks more. My plan was to install it this weekend but after looking at the wires going to the plug, and the questionable connectors/crimps from the previous owner, I decided it’s best to replace that section of the harness first. I know the alternator wire size is 10 gauge but can someone confirm what the correct gauge size of the D+, DF, and D- connections to the plug should be? Here’s a pic of what I’m replacing. Thanks!

19946233-33D8-4CE8-ABCA-D0BF2DCE6C3E.jpeg

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(edited)

The wiring diagrams in the Blue Book lists the area of the wires in mm2.  Here are those values.  The area is the number just before the color code.  Note that the earth and live wires are the same value for wire thickness.  The numbers don't exactly match our AWG units but you can get close.

Wire Gauge.png

AWG to mm conversion chart.pdf

Edited by halboyles

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That red wire is not happy. looks like the crimp is getting pretty hot. You have some high resistance there.

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18 hours ago, halboyles said:

The wiring diagrams in the Blue Book lists the area of the wires in mm2.  Here are those values.  The area is the number just before the color code.  Note that the earth and live wires are the same value for wire thickness.  The numbers don't exactly match our AWG units but you can get close.

Wire Gauge.png

AWG to mm conversion chart.pdf

Thanks halboyles- this is helpful!

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47 minutes ago, tech71 said:

That red wire is not happy. looks like the crimp is getting pretty hot. You have some high resistance there.

Yes tech71, that’s what I noticed as well. It should be much happier once I finish!

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37 minutes ago, Stevenc22 said:

solder those connections

 

This has been debated many times but I have had to replace numerous soldered connections on '02s that were subpar and dangerous.  The solder had creeped into the wire under the insulation and created a very stiff wire and melted insulation.  Also I don't recall any manufacturer using solder instead of crimping automotive connections.  You can, of course, do both types of connections well or poorly.  But a well crimped connection is exactly what the manufacturers use.  You'll need to get a good set of wire strippers and a professional set of crimpers.  If you are going to be doing even a dozen crimps, you should use properly sized connectors made with the Perma-Seal heat-shrink technology.  Slightly more expensive but they create a long term excellent connection.  I even put shrink wrap over the connections for more protection.

Gardner Bender Crimper.jpg

Perma-seal connectors.jpg

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31 minutes ago, halboyles said:

 

This has been debated many times but I have had to replace numerous soldered connections on '02s that were subpar and dangerous.  The solder had creeped into the wire under the insulation and created a very stiff wire and melted insulation.  Also I don't recall any manufacturer using solder instead of crimping automotive connections.  You can, of course, do both types of connections well or poorly.  But a well crimped connection is exactly what the manufacturers use.  You'll need to get a good set of wire strippers and a professional set of crimpers.  If you are going to be doing even a dozen crimps, you should use properly sized connectors made with the Perma-Seal heat-shrink technology.  Slightly more expensive but they create a long term excellent connection.  I even put shrink wrap over the connections for more protection.

Gardner Bender Crimper.jpg

Perma-seal connectors.jpg

Funny, I’ve YouTubed the crap out of both options, read numerous arguments for both and felt that soldering/shrink wrapping would’ve been a cleaner look. But  ultimately the more compelling evidence suggests that crimping is king! Thanks for for your thoughts and the perma-seal recommendation!

 

So the one thing I can’t figure out on my harness...from the alternator plug to the really poor splices the wire is 16g but from the splice down the harness the wire is 14g. And, the b+ red wire is of course 10g but prior to the burnt splice, there are two 14g wires. Is this standard?

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Just to add to the debate fun...

 

Solder sleeves are becoming increasingly prevalent in racing and aviation... All you need is a good heat gun...

Ring Terminals/Splices - Raychem Solder Sleeves

Having said that, I still favor a good crimp connection for anything high amperage like that alternator hot wire. But Halboyles is right. It is all about doing the connection right and protecting it with a decent shrink wrap. 

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All of the above heat shrink solutions are well and good, but how do you insert the tabbed spade connectors in the 3 wire plugs?

 

The brown, blue and black wires are all 1mm and really act as wires that carry the current between the voltage regulator and the alternator......That distance is (only) ~1 meter, so why don't you just make up a new harness instead of crimping two (40 year old) pieces together?

 

The red wire, at 4mm, should stand alone and not be crimped together for best efficiency.

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24 minutes ago, Einspritz said:

why don't you just make up a new harness

 

Excellent point.  And since the three-prong connectors are still available so you can replace them also:  https://www.repairconnector.com/bosch-voltage-regulator-alternator-repair-connector-3-female-wire-terminals/

 

When you see wires that badly overheated or corroded at the crimp, you can bet that the damage extends some distance form the end of the run.  Here is a pic of a wire I replaced just yesterday.  It was this black about 6 inches from the termination!  Also note that it is not just corroded around the perimeter but around each strand of the cable.  New wire on the right , original 45 year-old wire on the left.

20190410_150906.jpg

20190410_151003.jpg

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12 hours ago, Einspritz said:

All of the above heat shrink solutions are well and good, but how do you insert the tabbed spade connectors in the 3 wire plugs?

 

The brown, blue and black wires are all 1mm and really act as wires that carry the current between the voltage regulator and the alternator......That distance is (only) ~1 meter, so why don't you just make up a new harness instead of crimping two (40 year old) pieces together?

 

The red wire, at 4mm, should stand alone and not be crimped together for best efficiency.

 

Einspritz, I ended up cutting the crimps yesterday just to have a look at the copper strands and understand the harness more closely and decided making up a new harness is best so I'm in the process of sourcing new tabbed spade connectors (possibly from Belmetric) and primary wire (wirebarn?) and will make up the new harness. But, as I mentioned, immediately before the bad crimps, the brown, blue and black wires are 14g (1.5mm) and coming out of the crimps, they are 16g (1mm). I agree the red, 10g (4mm) wire shouldn't be crimped though I did expose both sides of the crimp and the copper looks good. Cheers, Mitch

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12 hours ago, halboyles said:

 

Excellent point.  And since the three-prong connectors are still available so you can replace them also:  https://www.repairconnector.com/bosch-voltage-regulator-alternator-repair-connector-3-female-wire-terminals/

 

When you see wires that badly overheated or corroded at the crimp, you can bet that the damage extends some distance form the end of the run.  Here is a pic of a wire I replaced just yesterday.  It was this black about 6 inches from the termination!  Also note that it is not just corroded around the perimeter but around each strand of the cable.  New wire on the right , original 45 year-old wire on the left.

20190410_150906.jpg

20190410_151003.jpg

halboyles, are you sure that wire on the left isn't superconductive black titanium?? just kidding, that looks bad! I did cut back my wires before and after the crimped section and found healthy looking copper. but, as Einsprintz suggested, I'll just make up a new harness for that area. Thanks, Mitch 

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