M38 : OK, Boomer

Start your project thread here for advice and for others to follow along with your project. This is a long term thread.

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Naugha
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Post by Naugha »

Slow progress. Lots of little setbacks. Zeno's Paradox.
Had some problems with the clutch pedal assembly that required trim job on a hat channel edge and adjustments to the linkage yokes.
Should be OK.

Working on the rear wiring harness. The 'Greek' harness is color coated.
Did a match of wire colors to wire numbers but the 'tail lights' have multiple tags with funky numbers.
Ended up firing up the lights to determine function. Will test the switch later.

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Don Alvarez
Retired HS Teacher
Central Florida
M38 Project
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RICKG
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Post by RICKG »

"funky numbers?" are you saying the tags on the taillight assy wired do not correspond as detailed here?
http://www.willysmjeeps.com/v2/modules. ... it&lid=116
keep 'em rollin'
RICKG MC 51986 DOD 01-52, '50 CJ3a
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Naugha
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Post by Naugha »

Hi Rick.
The tail light wires have multiple metal tags. None of the numbers match what should be there. The light cans have replacement guts which may explain the quirk. It’s like someone decided to attach some tags for the ‘look’.

I could have opened up the lights and checked what goes where but attaching a battery to each wire does the ID trick.

The rear harness wiring clips that came on the jeep are rotten. Just when I stopped being surprised at prices ..... snap. About $50 for a few clips.

You can see in the pics that I have the large cannon plug & numbered wire stub-outs for the front harness side of the two plug switch.

Wes has detailed album pics showing the harness that would (I think) work with my two plug switch..... and a chart that lists everything ... including the actual lengths of each wire & wire gauge in the bundle. Hmmm. I have the components and crimp tool. Was going to just buy the front harness but rolling my own could be fun. Just picked up a multipack of electrical tape from HF. 8)
Don Alvarez
Retired HS Teacher
Central Florida
M38 Project
RonD2
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Post by RonD2 »

Don,
Replacement (made in USA) metal wrap-around tags available here: https://www.keyesdavis.com/wrap-around-markers

I used their part number 2720-1 tag (photo below).
Part number 2701 is a close second.
Nice folks, if you call, they'll mail you free sample of each to see for yourself.

If I remember correctly the minimum buy was 350 at .14 cents each (about $50, delivered).

I have extras if you don't need that many. Let me know.

Not exactly the original font, but HF has a metal stamp punch set here: https://www.harborfreight.com/18-in-ste ... 63676.html
Rather be known as Zeno than Bubba... :lol:
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Ron D.
1951 M38 Unknown Serial Number
1951 M100 Dunbar Kapple 01169903 dod 5-51

“The only good sports car that America ever made was the Jeep."
--- Enzo Ferrari

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4x4M38
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Post by 4x4M38 »

The additional tags may correspond to wire numbers added/changed when turn signals are installed.
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Naugha
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Post by Naugha »

Thanks to all for the info.

Don
Don Alvarez
Retired HS Teacher
Central Florida
M38 Project
RonD2
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Post by RonD2 »

According to my notes:

Wire # - Description
460 - Turn Signal Lamp Feed, Right Front and Rear
461 - Turn Signal Lamp Feed, Left Front and Rear
467 - Light Switch to Turn Signal Switch Feed
Last edited by RonD2 on Mon Jun 06, 2022 8:35 am, edited 1 time in total.
Ron D.
1951 M38 Unknown Serial Number
1951 M100 Dunbar Kapple 01169903 dod 5-51

“The only good sports car that America ever made was the Jeep."
--- Enzo Ferrari

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Naugha
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Post by Naugha »

Oops. In my earlier post I mentioned some harness pics in the Wes album.

http://willysmjeeps.com/v2/modules.php? ... _photo.php

These are for the voltage regulator, not the front light switch harness. Very nice. Very useful ... but are there any pics out there that show the other front wiring harness components in this fashion, along with chart info on the wire length/ gauge details?

The VR harness pics/chart info above is the kind of construction info I need. You know... falling off a log, connect the dots, even Don could do it info.

The pics show where the VR harness bundle branches and the chart gives all the wire spec details..... kind of brings on tears of joy..... a beautiful thing :)
Don Alvarez
Retired HS Teacher
Central Florida
M38 Project
RonD2
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Post by RonD2 »

Closest I've seen searching old posts. There may be better......
http://willysmjeeps.com/v2/modules.php? ... t=wire+tag

The actual photo: Image
Full size view: http://willysmjeeps.com/v2/modules/gall ... C03119.jpg
Courtesy of management.
Ron D.
1951 M38 Unknown Serial Number
1951 M100 Dunbar Kapple 01169903 dod 5-51

“The only good sports car that America ever made was the Jeep."
--- Enzo Ferrari

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RICKG
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Post by RICKG »

I've got a jelly jar out there somewhere with random numbered tags. what numbers do you seek?
keep 'em rollin'
RICKG MC 51986 DOD 01-52, '50 CJ3a
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Naugha
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Post by Naugha »

Kendall‘s M38 harness chart is great.

Looks like the big challenge on the VR harness is finding a VR cannon plug with good pins and a few inches of good wire on each pin. I have read the threads on repairing cannon plugs but would rather not try that resto.

I think wire tag replacements will come at the end of my harness adventure.
Don Alvarez
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Central Florida
M38 Project
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wesk
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Post by wesk »

Looks like the big challenge on the VR harness is finding a VR cannon plug with good pins and a few inches of good wire on each pin. I have read the threads on repairing cannon plugs but would rather not try that resto.
Pins are usually no that difficult to find brand new and often can be found in both solder and crimp types. A plug with the 10 or 11 wires nipped off 2" from the plug and splice crimps all bunched up does not look nor function as well as a re-pinned plug. If the price of a specialty electrical crimp tool is prohibitive then just shop for the solder type pins. Pin removal tools are usually quite inexpensive.

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Original Army crimp tool

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Aftermarket crimp tool.

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Pin insertion/removal tool set.

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This TM has all the how too in chapter 5 Electrical Connectors

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Chap 5 index
Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100

Mjeeps photo album: http://www.willysmjeeps.com/v2/modules. ... _album.php
RonD2
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Post by RonD2 »

Naugha wrote:Looks like the big challenge on the VR harness is finding a VR cannon plug with good pins and a few inches of good wire on each pin. I have read the threads on repairing cannon plugs but would rather not try that resto.
Don,
What's the part number of the VR connector you seek?
Aren't there 2 connectors on the VR?

I believe the connectors are available brand new today, but if not anything remotely serviceable would do.
I'd be glad to wire up a new one or re-wire a used one for you, courtesy Uncle Sam's training.
Let me know.
Ron D.
1951 M38 Unknown Serial Number
1951 M100 Dunbar Kapple 01169903 dod 5-51

“The only good sports car that America ever made was the Jeep."
--- Enzo Ferrari

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Naugha
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Post by Naugha »

Hi Ron.
I ended up buying a rebuilt VBC-4002UT voltage regulator. Will need to do some ID homework on the two VR cables.

I have what looks to be the original VR to generator cable. The protective metal mesh was OK but the outside covering was bad so I wrapped it in electrical tape .... not sure if these old cables are reliable .. maybe replace?

The other cable (I think) is one of the two ‘VR to firewall’ cables (A&B) shown in the Wes electrical album.

http://willysmjeeps.com/v2/modules.php? ... _photo.php

BTW. I have the crimping tool Wes listed above/ top pic.
Don Alvarez
Retired HS Teacher
Central Florida
M38 Project
RonD2
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Posts: 2065
Joined: Wed Oct 01, 2014 6:00 pm
Location: South Carolina, Dorchester County

Post by RonD2 »

Hi Don,
I believe you'll discover that the military kept the same connectors and cables for commonality between VR's.
Early concept of "plug and play".
If you give the part numbers I'll BOLO for options.

I have a "megger" (megohmeter) to test shielded cable (what you call "protective metal mesh") for insulation breakdown.
The shielding is for radio noise suppression.

I'm pretty sure the pins in a canon-style plug like the VR are solder type (not crimp).

The crimp tool is used for Douglas and Packard style connectors.
Ron D.
1951 M38 Unknown Serial Number
1951 M100 Dunbar Kapple 01169903 dod 5-51

“The only good sports car that America ever made was the Jeep."
--- Enzo Ferrari

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