Vent System Tube Specifications for CJV-35/U and M-38

Specifications for Underwater Ventilation System Tubes and Lines
for CJV-35/U and M-38

Information provided by Keith Buckley and Bob Westerman

This information is published to aid in selecting the correct type tubing for restoring underwater ventilation systems on 1950 Willys CJV-35/U and 1950 - 1952 Willys M-38 Jeeps. This page is a supplement to the CJV-35/U Underwater Ventilating System and M38 Underwater Ventilating System articles.

Most of these vent tubes are found in the parts catalogs Group 0301-D for the CJV-35/U or Group 0304.5 for the M-38. Some of the ventilation system components are also found in other groups. It is important to remember the published Parts Listings are for Service Parts which may, or may not, be the same as Factory Installed Parts. There are many documented errors in the published Service Parts Catalogs.

Notes about tubes and lines;
The words "Tube", "Line" and "Tubing" are used to describe the vent piping in these Jeeps. Tube or Line is the nomenclature used to describe the complete pipe assembly ready to install on a Jeep. A Tube or Line consists of a specific length of Tubing, possibly with sections of loom installed, and a fitting on each end. Tube or Tubing is the bulk raw material that's used with the other components to make up a specific Tube or Line.
In the factory specifications we see the materials "Bundy steel tubing" and "copperbrazed tubing". These are both steel tubing with a copper, or other non-ferrous coating or plating. The tube color could be silver or copper depending on the manufacturer. A magnet will be attracted to these steel lines so it is the best method to determine the base material type. Some factory underwater vent lines are made from copper or brass and a magnet will not be attracted to these lines. The parts manuals often indicate a specific tube is steel, but a service replacement part is to be made up from bulk copper tubing. Copper tubing is easier to bend but not as strong as steel.

Do you have an unrestored CJV-35 or M-38?. If so please do the magnet check on your tubes and let us know if they are copper or steel. Click here for Contact Information.

The vent tubes are listed in numerical order using Willys-Overland part numbers. Following each part number is a brief description of the tube location on the vehicle. Then are one or more numbered sections with detailed information from various sources, as appropriate. Buy using multiple sources of information we can determine more about each line. Last is a brief summary of the tube.

WO Part Number - Location on Vehicle
1. Original Factory Specifications
2. Parts Catalog for Truck V-35/U, approved 1 Feb., 1950
3. ORD 9 SNL G-740 List of all Service Parts of Truck, Utility: 1/4 ton, 4 x 4, M38. November 1951
4. ORD 9 SNL G-740 List of all Service Parts of Truck, Utility: 1/4 ton, 4 x 4, M38. September 1955
5. Summary

117504 - CJV-35 distributor to special orifice fitting at wiper vacuum tee
2. Tube, vent, timer to intake manifold, assy

A-12935 - All, tee to tee (or elbows) on dash
1. Vent tube Assembly (tee to tee on dash) for MB-Navy Basic, created 3/19/47. Material - Steel, Bundy Steel tubing, tinned or copper plated all over developed length of approx. 17-1/2 inches, Optional - Rochester Products Inc., Single wall copperbrazed tubing
2. Tube, vent, assembly, 17-1/2” long
4. TUBE, VENT, assy. Composed of:2 142431 NUT;1 TUBE, Steel, seamless, plated, 3/16 OD, 0.030 thkns of wall (use (18 in) TUBING 44-T-5080-10)
5. This same part is used in the MX-735/MR kits, CJV-35s, M-38s and early M-38A1s.

A-17742 - CJV-35 fuel tank to left dash tee.
1. Gas Tank Cap Vent to Tee Tube Assy - MB Navy-Basic, Released for production 5/22/45, Material - Annelaed Brass or Copper Tubing 1/32 wall, 3/16 OD. 54-1/4 overall length. Loom 30" overall length, Assemble Nuts #53668-U and loom #A-17444-D in place before flaring end of tube.
2. Tube, fuel tank vent to tee, assembly, 54-1/4” long
5. On existing vehicles surveyed this line is copper.

A-17866 - CJV-35 carburetor to air crossover pipe
1. Carburetor Ventilator Tube Assy - MB NAVY 10-45, Material - Steel, Bundy Steel Tube or Rochester Products Inc. Single wall welded tubing. Tinned or copper plated all over. Ends are 53894-U, effective 1/17/49 ends were changed to GM137398 both ends, GM142247 - Optional
2. Tube, ventilating, carburetor, assembly
5. 5/16"

648080 - CJV-35 distributor to air crossover pipe
1. Ventilation tube assy - CJ-V35, MB service (Timer to air cleaner) created 8/3/48, Material - Steel, Bundy Steel tubing, tinned or copper plated all over developed length, Optional - Rochester Products Inc., Single wall copperbrazed tubing

648081 - CJV-35 and early M-38 (before engine serial No. 74419) transfer case to right dash tee
1. Transfer case vent to tee tube assy - CJ-V35 created 8/3/48, Material Bundy steel tube or Rochester products inc. single wall welded tubing tinned or copper plated all over.
3. Tube, Steel, 3/16 OD x 25 dev lgh.
4. TUBE, transmission case vent to tee, assy. Composed of: 2 142431 NUT;1 TUBE, Steel, seamless, plated, 3/16 OD, 0.030 thkn of wall (use (25 in) TUBING 44-T-5080-10)

648704 - CJV-35 master cylinder to left dash tee
1. Master cylinder to tee tube assy CJ-V-35 created 12/23/48, Material - Steel, Bundy Steel tubing, tinned or copper plated all over developed length,
Optional - Rochester Products Inc., Single wall copperbrazed tubing
2. Tube, ventilation, master cylinder to tee, assembly, 23” long

800059 - CJV-35 air cleaner to right dash tee
1. Vent tube 3/16 dia (air cleaner to dash tee) CV-V35 created 8/29/49 Ref L-12177-AR, Material - Steel, Bundy Steel tubing, tinned or copper plated all over, Optional - Rochester Products Inc., Single wall copperbrazed tubing
2. TUBE, vent, air cleaner to dash tee, assembly

800374 - M-38 distributor to air crossover pipe
1. Ignitor Vent Tube Assy (Ignitor to Air cleaner tube) MC Created 10/4/49 16 inches long - Material .1875 Soft Copper Tubing Inverted flare tube nuts GM137396 (2 reqd) shortened to 10 inches long 2/8/50, shortened to 9 inches long on 5/10/50.
3. Tube, copper, 0.1875 OD x 9 dev lgh
4. TUBE, IGNITOR VENT, assy. Composed of: 2 142431 NUT; 1 TUBE, copper, seamless, plated, 3/16 OD, 0.030 thkn of wall (use (9 in) TUBING 44-T-5080-10)
5. Copper tubing was used for distributor vent lines on the M-38 possibly to make ignition timing adjustments easier.

800375 - M-38 distributor to special orifice fitting at wiper tee
1. Ignitor Vent tube Assy - Ignitor to Windshield Wiper Fitting - Created 10/4/49, .1875 Soft Copper Tubing 30" long. was shortened to 27 inches 5/10/50.
3. Tube, copper, 0.1875 OD x 27 dev lgh.
4. TUBE, IGNITOR VENT TO WIPER, assy. Composed of:2 142431 NUT; 1 TUBE, copper, seamless, plated, 3/16 OD, 0.030 thkn of wall (use (27 in) TUBING 44-T-5080-10)
5. Copper tubing was used for distributor vent lines on the M-38 possibly to make ignition timing adjustments easier.

800701 - M-38 fuel tank to air filter
1. Created 12/16/49, and modified to be 72" long on 2/8/50. Material - annealed brass or copper tubing 1/32 wall. The loom length covering it was 45", and later made into 2 pieces, one 30" and the other approx 14" 0n 4/17/50. On 5/10/50 the overall length of the tube was increased from 72" to 86". On 6/20/50 the overall length was increased from 86" to 88". On 7/25/50 the tube and loom were specified separately as loom 802297 and tube 802296.
3. Tube, Steel, 3/16 OD x 86 lg.
4. Tube, gas tank vent, assy Composed of: 2 142431 NUT; 1 WO-802247 LOOM, 5/16 ID x 45 in lg; 1 TUBE, Steel, seamless, plated, 3/16 OD, 0.030 thkn of wall (use (86 in) TUBING 44-T-5080-10)
5. This line is made from copper according to factory specifications and there are no notes indicating it was ever steel or copper plated steel. Service parts catalogs state the line is steel. An informal survey of unrestored vehicles indicates copper lines were actually used for this vent.

801077 - M-38 air filter to right dash tee (early) or elbow (late)
1. Created 12/16/49, and released for production 5/29/50. Material - tinned or copper plated all over, Optional - Bundy Steel tubing, Rochester Products Inc., single wall welded tubing, 3/16 OD, flare nuts are GM137396 both ends, or GM142431 optional.
3. Tube, Steel, 3/16 OD x 12 dev lgh.
4. TUBE, VENT, assy. Composed of: 2 142431 NUT;1 TUBE, Steel, seamless, plated, 3/16 OD, 0.030 thkn of wall (use (12 in) TUBING 44-T-5080-10)

801271 - M-38 master cylinder to left dash elbow
1. Master cylinder to elbow tube assy - MC created 2/20/50, Released for production 5/10/50, Bundy Steel tubing or optional Rochester products Inc. Double wall copper brazed tubing, tinned or copper plated all over developed length.
3. Tube, steel, 3/16 OD x 30 dev lgh.
4. TUBE, master cylinder to elbow, assy. Composed of:2 142431 NUT; 1 TUBE, Steel, seamless, plated, 3/16 OD, 0.030 thkns of wall (use (30 in) TUBING 44-T-5080-10)

801586 - M-38 carburetor to air crossover pipe
1. Carburetor Ventilator Tube Assy 3/16 MC create 4-7-50, Released for Production 5/10/50, Material - steel - Bundy steel tube -optional- Rochester Products Inc, Single wall welded tubing, tinned or copper plated all over.
3. Tube, steel, 3/16 OD x 13 dev lgh.
4. Tube, carburetor ventilator, assy Composed of: 2 142431 NUT; 1 TUBE, Steel, seamless, plated, 3/16 OD, 0.030 thkn of wall(use (13 in) TUBING 44-T-5080-10)

807495 - M-38 (late only, after engine serial No. 74419) transfer case to bellhousing tee
1. Pressure tube assy - bell housing to transfer case M.C., New, Release for production 2/1/52
Material - steel - Bundy steel tube -optional- Rochester Products Inc, Single wall welded tubing, tinned or copper plated all over
4. Line, bell housing to transfer case, assy Composed of: 2 NUT 142431; 1 TUBE, Steel, seamless, plated, 3/16 OD, 0.030 thkn of wall (use 22 1/2 in TUBING 44-T-5080-10) (used on engines after serial No. 74419)

807574 - M-38 (late only, after engine serial No. 74419) bellhousing tee to special check valve at fuel pump center section
1. Pressure tube Assy (pump to bell housing) MC .19 OD One end is GM142431 or optional GM137396, the other end is GM-144307, opt GM-191265, opt GM-120704, opt GM-191266. Material: Bundy Steel Tube or Optional Rochester Products Inc. - single wall welded tubing, tinned or copper plated all over, all radii 1.0 on C/L except as noted.created 2/11/52
4. Line, vacuum pump to bell housing, assy Composed of:2 NUT 142431;1 TUBE, Steel, seamless, plated, 3/16 OD, 0.030 thkn of wall (use 27-7/8 in TUBING 444T-5080-10)(used on engines after serial No. 74419)

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