Correct gauges for 1955 M38A1...

JBJeep · Post by **JBJeep** » Thu Dec 09, 2021 6:10 pm

I'm trying to confirm the gauges in my newly acquired 1955 built M38A1 are correct:

Batt-Gen Indicator # 8376377...
Fuel #8376374 (howver, it might need replacing...shows a 1/4 tank when off).

According to the military parts manual (ORD 9 AND G-758, Sept '56)
those numbers are correct for the unit.
-------------------------------------------
However, these are not listed as correct in the manual...but they work.
Temp # 24543-2 (Reads to 24O°)
Pressure (to 120lbs) #8674895,

Are these correct military gauges, just later than the 1956 date of the manual? Perhaps M151 stuff?
Are they still correct for a M38A1 and changing them would be like putting (correct) Toledo air in the tires? (Doable, but why?

)

Post by **wesk** » Fri Dec 10, 2021 2:50 am

Batt-Gen Indicator # 8376377...
Fuel #8376374 (howver, it might need replacing...shows a 1/4 tank when off).

According to the military parts manual (ORD 9 AND G-758, Sept '56)
those numbers are correct for the unit.
-------------------------------------------
However, these are not listed as correct in the manual...but they work.
Temp # 24543-2 (Reads to 24O°)
Pressure (to 120lbs) #8674895,

8376377 Original volt meter used on the M170. Eventually it found it's way onto most M38's, M38A1's when they had their mechanical voltage regulators replaced with the newer transistorized ones.

8376374 Fuel gage originally introduced on the M170 and later M38A1's after serial MD70114.

MS24543-2 is a much later temp gage with rubber Packard type connectors found on M151 and many other 1975 & newer MV's.

8674895 (MS24540-2) another very late issue 120 PSI oil press gauge found on the much newer MV's.

You will find an almost overwhelming number of MV dash gauges & senders listed in the M38A1's ORD 9 SNL G-758, ORD 7 SNL G-758, TM 9-2320-208-20P 1959, 1966 copies and -34P. All M38A1 manuals

JBJeep · Post by **JBJeep** » Fri Dec 10, 2021 1:24 pm

Wes, thanks.

I have the G-758 manual and it has provided me all the numbers I can use...and then some. That's how I new which units were correct.

So...I'm looking for a new
Temp gauge: 8376379
Oil Pressure guage: 7728853, 795430 or 8376380

Also, my Speedo has a broken glass lens. Can it be repaired?
Checking vendors, no one sells a correct speedometer replacement unit with CORRECT ORD # 8376375 markings ...they all only sell MS 39021-2.

(And anything marked MS is too new, and not period correct for my '55, right?) I'd like to avoid later style M151-era parts.

Any help or points in the right direction would help!

RonD2 · Post by **RonD2** » Fri Dec 10, 2021 8:43 pm

Hi JB,
Should be posted in the wanted section, but here you go:

https://www.ebay.com/itm/275043630279?h ... SwlblholXu

https://www.ebay.com/itm/173804501937?h ... SwAdhcbhPL

Good luck!

Post by **wesk** » Fri Dec 10, 2021 10:55 pm

Just make sure the sender is matched to the gage for the oil pressure and fuel quantity.

I live out in the boonies of NW Wisconsin. The nearest large town has a population of 105,000 and is 45 miles away but it has a speedometer overhaul shop. Finding one near you is your best bet for your speedo.

Finally grounding is an extremely important part of making gages work correctly. We spend way to much time covering our jeeps with layers of paint and most of the time ignoring grounding needs where small areas must be left unpainted. Some of your gages need a case ground to complete the motorization circuit within the gage as well as the circuit completing ground thru it's sender. The gage housings, clamps, cluster frame must have bare metal contact areas. The cluster frame must have bare metal contact areas between the 4 fasteners, the cluster frame corner holes and the dash fastener receptacles. I prefer to add a ground strap to the cluster frame and to the dash to insure a good ground. Also the gas tank needs the same bare metal contact areas for the sender and I add a ground strap from the tank to the body tub. That ground strap between the engine and the right front engine mount is important as well.

JBJeep · Post by **JBJeep** » Sat Dec 11, 2021 9:36 pm

Wes
Great minds think alike!
Yesterday, I was speaking with my neighbor, a retired dealership service manager and all around car guy. He was bemoaning the lack of a local Speedo shop. He said back in the old days every decent sized town had one. Seems our local guy retired 15 years ago.
None the less, I'll double check. I also have an email to a national shop.

As a former upper Midwest resident, I've found that your region is often better staffed in old car stuff than those of us in the Pacific Morthwest. I have no doubt I'm sure I'd be set of I lived in Indy or Ohio...it even eastern Wisconsin. I have car friends in Milwaukee...a very industrial town with car infrastructure.

Thanks for the tip about grounding. The guy/shop doing the paint is a career. MV guy, so he knows the ins and outs of Jeeps (and M-series and Unimogs, etc), so I'll figure he has a handle on it.
Also, my last project was a Studebaker Avanti...nothing like a fiberglass body to remind you about the necessity of good grounds!