USAF/USMC Forward Air Controller (FAC) Jeeps

1950 - 1968, M38, M38A1, M170, modifications, sugestions, and ideas, official MWO's and unofficial field mods.
Post Reply
Mongo
G-Private
G-Private
Posts: 3
Joined: Thu May 01, 2008 7:50 pm
Location: Scottsdale, AZ
Contact:

USAF/USMC Forward Air Controller (FAC) Jeeps

Post by Mongo » Sat May 03, 2008 9:41 pm

I would like to hear from anyone who has knowledge or experience with the TRC-75 1 KW HF SSB installation in the M-38A1 (MRC-87), also with the GRC-19 HF radio installation in the same. I am restoring a 1954 A1, and plan on finishing it as a FAC jeep. I am in particular looking for 100A generator (alternator) bit, I have the alsternator, regulator, rectifier and cables, but no pulleys, mounts, hardware, idler, oil pressure switch, etc.

regards,
Scott Johnson
1954 M-38A1
1954 English Electric Canberra B.2 (X2)
Scott Johnson, W7SVJ


Joe Gopan
Jeep Heaven
Posts: 49841
Joined: Sun Mar 02, 2008 12:37 pm
Location: Proving Ground

Post by Joe Gopan » Sun May 04, 2008 6:35 am

You will need spare waterpumps on hand, 4 belts tightened with a prybar give short waterpump life. When you key the mike with the '19 the Jeep lurches sideways at fast idle. Best regulator is carbon pile.We had three of these set , an M-38A1, M-37, and an M-135, all ate waterpumps.
2011 MVPA PIONEER AWARD - MVPA #1064
HONOR GRAD-WHEELED VEHICLE MECHANIC SCHOOL 1960 - US ARMY ORDNANCE SCHOOL(MACHINIST) ABERDEEN PG 1962 - O-1 BIRD DOG CREWCHIEF - 300,000+TROUBLE FREE M-38A1 MILES
LIFE MEMBER AM LEGION-40/8-DAV
7 MIL SPEC MAINTAINED MV'S
COL. BRUNO BROOKS (ARMY MOTORS) IS MY HERO

Cuz
G-Lieutenant General
G-Lieutenant General
Posts: 6672
Joined: Fri Feb 23, 2007 10:26 am
Location: Northwestern Wisconsin
Contact:

Post by Cuz » Sun May 04, 2008 8:40 pm

The radios were for calling in a wrecker to pull the A1 home! :wink:

Try this link:
http://webs.lanset.com/buzz/index1.html
Cuz (AKA Wes K)
45 MB, 51 M38, 54 M37, 6? M101A1, 60 CJ5, 76 DJ5D & 47 T3-C

Joe Gopan
Jeep Heaven
Posts: 49841
Joined: Sun Mar 02, 2008 12:37 pm
Location: Proving Ground

Post by Joe Gopan » Sun May 04, 2008 8:59 pm

We were taking some M-38A1s out of storage, one had flat batteries, I towed it two miles out and back without it starting. I did not realize it had the 100Amp system and would not generate a spark.
2011 MVPA PIONEER AWARD - MVPA #1064
HONOR GRAD-WHEELED VEHICLE MECHANIC SCHOOL 1960 - US ARMY ORDNANCE SCHOOL(MACHINIST) ABERDEEN PG 1962 - O-1 BIRD DOG CREWCHIEF - 300,000+TROUBLE FREE M-38A1 MILES
LIFE MEMBER AM LEGION-40/8-DAV
7 MIL SPEC MAINTAINED MV'S
COL. BRUNO BROOKS (ARMY MOTORS) IS MY HERO

Joe Gopan
Jeep Heaven
Posts: 49841
Joined: Sun Mar 02, 2008 12:37 pm
Location: Proving Ground

Post by Joe Gopan » Sun May 04, 2008 9:09 pm

Units using the M-38A1 with 100 Amp system were issued a Water Pump Pully Puller in order to convert new water pumps with the two-belt pulley. We used to install the 100 Amp kits in the Motorpool. I would hate to hack a nice M-38A1 full of holes to install all the Coaxial Cable and accessories, holes had to be cut in the side of the Radiator Guard for the cables to the rectifier. The kit was also installed in some M-38s, it sure filled up the engine compartment and the space in front of the radiator. It takes a special person to maintain the system as the Carbon Pile Regulator requires periodic adjustment. The 100 Amp system has a characteristic loud whine.
2011 MVPA PIONEER AWARD - MVPA #1064
HONOR GRAD-WHEELED VEHICLE MECHANIC SCHOOL 1960 - US ARMY ORDNANCE SCHOOL(MACHINIST) ABERDEEN PG 1962 - O-1 BIRD DOG CREWCHIEF - 300,000+TROUBLE FREE M-38A1 MILES
LIFE MEMBER AM LEGION-40/8-DAV
7 MIL SPEC MAINTAINED MV'S
COL. BRUNO BROOKS (ARMY MOTORS) IS MY HERO

User avatar
petesilfven
G-General
G-General
Posts: 8933
Joined: Tue Mar 09, 2004 2:07 pm
Location: Dearborn, MI

Post by petesilfven » Sun Aug 10, 2008 10:33 am

I think you might have the wrong radio package. FAC requires UHF, VHF, and VHF-FM equipment. You're talking to aircraft and ground units.
MVPA 21473, GLMVPA
USN 1959-65 USS GALVESTON CLG3
NRA Benefactor Member

RadioJeepMan
G-Sergeant Major
G-Sergeant Major
Posts: 181
Joined: Mon Dec 30, 2002 11:59 am
Location: Crete, ILL MVPA 437

Re: USAF/USMC Forward Air Controller (FAC) Jeeps

Post by RadioJeepMan » Mon May 11, 2009 6:47 am

Those M38A1's & M170 were fitted with the Leece Neville 100 Amp alternator system that was modified to 150 amps by performing a Collins Radio modification to the alternator stator. Along with a protective diode in the regulator.

Also, those FACs as fitted with the TRC-75 were HF 2-30 Mc as installed in M38A1's & M151's (I have seen no documentation for an M38 install, however I'm not saying they were not). The M170's as fitted as FACs with the TRC-75 were HF 2-30 Mc AND a UHF system 200-400 Mc ARC-55. They carried no VHF.

Conversely, my boss flew the OV-10 Broncos in Viet Nam. Those were fitted with HF VHF & UHF. He said that the HF was used for ship to shore/shore to ship which are usually 30 miles off shore. His commo to the ground was almost exclusively VHF, and indicated that UHF was rarely used.

Paul Vandervort
MVPA 437
KB9PZC
Paul
MVPA 437
FAA A&P
FCC General

RadioJeepMan
G-Sergeant Major
G-Sergeant Major
Posts: 181
Joined: Mon Dec 30, 2002 11:59 am
Location: Crete, ILL MVPA 437

Re: USAF/USMC Forward Air Controller (FAC) Jeeps

Post by RadioJeepMan » Mon May 11, 2009 9:47 am

As for all those who have concerns about the water pumps. The proper installation for this vehicle is that three belts drive the alternator solely through shorty belts. The water pump is only driven by one belt used in the aft belt groove and adjusted via an idler pulley. Although having that four groover hangin out there is a larger mass than I like to see. The 100 amp mod kit I have info for carries a Willys Overland number and a G758 prefix part number so I dont think it is restricted to the FAC typical installation. It also indicates it it applicable to most of the GRC-, VRC- VRQ radio set installations so it looks like a typical upgrade for radio equipped vehicles that require a larger current capacity.

Paul Vandervort
MVPA 437
KB9PZC
Paul
MVPA 437
FAA A&P
FCC General


Post Reply

Return to “M38, M38a1 Modifications”

Who is online

Users browsing this forum: No registered users and 35 guests