Adjustment and configuration differences aside, will the 4004ut work as a replacement? It would still regulate 24 volt system, no? _________________ Gary Keating
1949 C3A, 1952 M38,
1954 M170, 1957 Cj3B
Can't say. Voltage and Amperage regulation in any 24 V system must be configured (ie wired) precisely and regulated accurately. This is a test process you will need to have the fire bottle standing by for! _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
The M38 ORD 9 only offered the VBC4002UT. The M38 ORD 8 Jun 56 offers VBC4002UT and an alternate VBC4003UT. The M38A1 ORD 9 and much later TM 9-2320-208-20P offers the VBC4003UT as an approved sub. None of the M38/M38A1 parts manual list a VBC4004UT! The late M38A1 TM 9-2320-208-20P also offers the Leese-Neville transistorized regulator used on the M151 as a sub for the VBC4003UT. _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
I have never found an ORD 9 or ORD 7 or ORD 8 for the M151 series. There are several issues of TM 9-2320-218-20P (Organization Parts List) and several issues of TM 9-2320-218-34P (Depot Level parts list). The -20P's offer up the 25 amp transistor type regulator only. Both -20P & -34P offer up the 24V / 25A generator but neither show a conventional VBC-400_UT series regulator.
Quote:
2920013076875 NSN still available?
I googled it and got quite a few hits. _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
interesting find in the 1966 TM 9-2320-208-20-P manual for the m38a1,m38a1c, and m170.
though there is no mention of the vbc 4004ut in the parts lists, there is a photo of a voltage regulator in the manual on page 41. Also, on (the visual guide to parts0 section at the front of the manual, there is a drawing labeled regulator and stating it as a vbc4004ut. i have inclosed photos.
when enlarged, the vbc4004ut can be seen clearly!!!!!
proved the VR existed at that time (1966). With m38a1 production into 1971, and the m151 starting production in 1960, ,its quite possible the vbc4004ut was utilized. _________________ Gary Keating
1949 C3A, 1952 M38,
1954 M170, 1957 Cj3B
Ron, did you read the Yellow Autolite manual pages specs? The 4004 is noticeably different internally on specs.
Keats,
As Don said all three regulators look identical from the outside except for numbers. The Army's Tech Order folks have used many photos and illustrations of a item to simply show it's shape and appearance in those manuals which were not the specific intended part number. So it is not odd to see the faximalty of a basic VR40XX series reg in a IPL illustration and not see that particular samples part number in the text.
As I stated above there are subtle internal differences in specs that may or may not have ill effects if they are used in place of the the other two. It's quite clear you are getting no assurances or guarantees the 4004 will work from our membership. It is a "Your option to trying it!" deal. _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
solid state VR's are very different yet they seem to work with a volt meter instead of a amp gauge. Will continue search for more info. _________________ Gary Keating
1949 C3A, 1952 M38,
1954 M170, 1957 Cj3B
Good point. The Army switched to the Solid State regulators almost completely across the board for all the 24V 25A systems in the late 50's. However we are still unable to find a documented approval for substitution of a 4004 for a 4002 unit. _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
Joined: Mar 25, 2006 Posts: 45 Location: Austin, TX
Posted: Sun Mar 05, 2023 3:11 pm Post subject:
I have a NOS 4004 and the mounting configuration for an M38 is totally different in these pictures. The various manuals and resto books have different mounting brackets for both M38 and M38A1.
One shows a M38 with a splash plate mounted to the two welded to frame brackets and the regulator mounts on that I guess.
The M38 manual shows just the frame brackets and two aluminum brackets attached to the regulator which then gets mounted to the frame brackets bolted to the 4 rubber cushion/ground straps attached.
The m3A1 drawing shown in this thread shows the 4004 regulator mounted with the two aluminum brackets (which isnt possible because there are no threaded holes to screw into)
and the these long C shaped brackets that mount it to the frame brackets.
Are the C shaped brackets still available? Ive never seen them anywhere.
I will post pics of what I am poorly describing asap.
The M38 & M38A1 have many clear and detailed photos of their regulator mounts thru-out this web site and their TM's and Parts Manuals. The problem is there is no official Army pub showing the actually listing the 4004 unit as a legitimate sub for the 4002 & 4003 units they do list.
Bottom line are the Autolite Spec sheets. You will be at risk of damaging your system since the specs are a bit different.
Here's the M38 regulator mount from an M38 manual:
Here's the M38A1 regulator installation from TM 9-8014
Here's the Autolite Spec sheet set for the 4000 series regulators discussed here:
When the M151 came out in 59/60 and introduced the 4004 unit they also published a very detailed set of setup sheets for it. If you absolutely insist on experimenting with 4004 unit in early model vehicles I would suggest you get very familiar with these sheets as well.
You should also be using the proper TM for the Autolite accessories TM 9-1825B dated 1952 or newer. The Army abandoned this manual in the 70's and started opening new individual unit repair and parts manuals. _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
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