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Replacing M4 Tank Final-Drive Assemblies

Instructions for replacing the final-drive assembly on the M4 Sherman tank, from Army Motors, Vol. 6, No. 2, Maintenance Division, Office, Chief of Ordnance, May 1945.

Replacing M4 Tank Final-Drive Assemblies

Time was when M4 medium tanks with damaged power trains had to run home to mother for mending–like little apple-filchers with buckshot in their final drive assemblies. Now, when your M4-series job (or related gun or howitzer motor carriage) has something more like dribble where the drive should be, you don’t have to pack it off to some 4th-echelon tank hospital for a slow cure. Instead, you can put in a whole new controlled differential and transmission final-drive assembly right there in the field, according to TB ORD 275.

Four of these assemblies, complete with everything but whistles, have at last been made authorized items of issue for lower echelon installation. They are:

—  1-piece differential housing, single-anchor-brake type, Ord. Part No. A5700061, Official Stock No. G104-5700061.

—  1-piece differential housing, double-anchor-brake type, Ord. Part No. A5700062, Official Stock No. G104-5700062 (Fig. 1).

—  3-piece differential housing, single-anchor-brake type, Ord. Part A5700060, Official Stock No. G104-5700060 (Fig. 2).

—  3-piece differential housing, double-anchor-brake type, Ord. Part No. A57000196, Official Stock No. G104-57000196.

They’ll be assembled at your favorite base shop or Ordnance supply depot from parts and housings already in stock or made available through cannibalization. No important difference between any of them, and they’re all yours for the asking.

Final Drive Assembly

All you have to do is install ’em and send back the has-beens. But remember that the whole system will break down if you don’t send back complete assemblies. Only the final-reduction sub-assemblies (A294625) should be removed from a damaged unit before its sent to the rear for reconditioning.

Continue reading Replacing M4 Tank Final-Drive Assemblies

Jeep Sling

Instructions for making a jeep lift bar from the 881st Ordnance HAM Company, from Army Motors, July 1945.

JEEP SLING
TO GIVE 1/4-TONS A LIFT WITHOUT ALSO GIVING ‘EM A PAIN IN THE REAR END

Ordinarily, when you evacuate a helpless jeep and have to lift it on or off a cargo truck with your wrecker, the victim is hoisted by wrapping a chain around it. This gets it where it’s going. But often the jeep is in even worse shape when you’re through because the chain damages the body. To prevent a lot of unnecessary repair work, the 881st Ord. HAM Co. got busy and devised a simple sling that holds the jeep firmly but never leaves a mark.

Jeep Sling Figure 2

The sling is made of a reinforced 6″ I-beam, a chain with a hook at one end, two chains with hooks on the other end, and two heavy metal rings near the center of the beam. You reinforce the I-beam on both sides, preferably with U-channel iron if you’ve got it; otherwise use plate. It’s better not to extend these reinforcements along the beam’s full length or it’ll increase the sling’s weight considerably. Instead, you can place one at each end and overlap them in the center for added strength under the ring holes.

In case you can’t find an I-beam, two pieces of frame side-rail bolted or welded together will do just as well and you won’t have to bother to reinforce it. You’ll find the exact dimensions for building the sling in Fig. 1.

Jeep Sling Figure 1

To put this sling to work, first lower the top and windshield of the 1/4-ton and see that the rear seat is level with the back edge of the body. Then place the I-beam lengthwise over the jeep with the single-chain end to the rear (Fig. 2). Hook the single chain in the pintle, or if there isn’t any, under the rear edge of the frame. Then hook the other two chains under the two frame-ends supporting the front bumper. After you place the wrecker hook through the center rings, you can gently lift the jeep to where you want it with nary a slip.

 

The Secret of the Russians’ Success

Secret of Russian Success, Preventive Maintenance

Army Motors, March 1945


 

How’s Your Dodge, Rog?

“How’s Your Dodge, Rog?” from Army Motors, Chief of Ordnance, August 1944.

Hows Your Dodge, Rog?
 

M4 Track Tension

Illustration of correct and incorrect track tension on the M4A2 tank from the M4A2 technical manual. The tank crew were instructed to inspect the track tension regularly and tighten the track if it shows noticeable sag.

M4 Sherman Tank Tracks

Track with insufficient tension

Tank Tracks

Track with proper tension

Source: TM 9-731B: Medium Tank M4A2, War Department Technical Manual, January 1943.
 

Vacuum Windshield Wipers for Jeeps

Maintenance notice about new vacuum windshield wiper kits for jeeps from Army Motors, Vol. 6, No. 2, May 1945:

Vacuum Windshield Wipers for Jeeps

Some of you jeep herders can start riding “no hands”—as far as your windshield wipers are concerned. A new vacuum-operated windshield-wiper kit, Item Stock No. G503-5700249, is being issued for ¼-tons in areas where the rain is heavy and the downpour season long. A TB, out soon, will give the authority and parts numbers.

Jeep Vacuum Windshield Wipers

Fig. 1—Into each life some rain must fall. But it won't bother you if your jeep qualifies for these vacuum windshield wipers.

The kit’s complete with two motors, arms and blades, tubing, hose, clamps, and fittings to do the job. All you need’s a few tools and a little energy. Fig. 1 shows the finished installation.

Remember, this kit’s for where it keeps rainin’ all the time, practically, and both hands are better off on the wheel.

Kits are expected to be available this month (May), but don’t bust your pencil making out requisitions unless you qualify as a long-term rain-in-the-face.

 

The New AR 850-15

Summary of vehicle painting and maintenance instructions from AR 850-15 from Army Motors, Vol. 6, No. 6, September 1945.

New AR 850-15 Painting Regulations

THE NEW AR 850-15

The law on “Miscellaneous—Motor Vehicles” gets a major overhaul for the first time in two years. This’ll help you get hep to what’s what.

Changes that affect you—because they affect vehicle operation and maintenance—blew in with the newly-revised AR 850-15 (1 Aug. 45). New do’s and don’t’s, new words like “semigloss” and “full gloss” have been written into the regulations. And a lot more, too.

NEW PAINT

Good news for maintenance men who’ve long been bitching about lusterless OD breaks out in par. 7, which prescribes approved semigloss olive drab for vehicles (certain ones excepted). The new paint is Enamel, olive drab, rust-inhibiting, U.S. Army spec. 3-181, amendment 3, type V—Fed. Stock No. 52-E-7574 for a 1-gal. can, 52-E-7574-75 for a 5-gal. can. But don’t start requisitioning it now—the stuff won’t get into supply channels for 60 to 90 days, and anyway, you only put it on when the vehicle’s due for a repaint. ASF Circular 291 (1 Aug. 45) says: “The new painting procedure… will be applicable to U.S. Army motor vehicles now in use, other than those excepted… when the vehicles require complete refinishing in accordance with established maintenance schedules and upon the availability of the semigloss paint prescribed.”

On busses, ambulances (except 3/4-ton 4×4’s), and passenger sedans, the AR goes whole hog on gloss. It says they may be painted a full gloss OD—but not until a repaint is necessary.

Continue reading The New AR 850-15

Removing Inner Bogie Wheels on Horizontal-Volute Suspension

Instructions for removing the inner bogie wheels on the M4 tank with horizontal-volute spring suspension (HVSS) from Army Motors, Vol. 5, No. 11, February 1945.

SPECIAL TOOLS FOR YOUR NEW H.S./M.F.T.
Meaning: Horizontal-Suspension M-Four Tank. If that is your brand, this SOP is your oyster.

If you’re an M4-series medium tankman. with a new-fangled horizontal-volute suspension to nurse, you’ve a break comin’ that’ll help with your chores. A new set of special tools just issued to the 2nd and higher echelons makes a couple of tough jobs a damn sight easier—to wit, removing the volute springs from the suspensions, and taking off an inner bogie-wheel.

As you know if you’ve seen them, these horizontal-volute suspensions come with two types of tracks—the T66 with all-steel track-shoes, and the T80 with rubber-shod track-shoes. If you’ve got a T66, you can use the riser block as originally designed, but if it’s a T80, be sure to use the modified riser block. Any or all volute springs can be removed while the center bogie-assembly is raised up on the jack. We posed the T66 for the revealing photos that follow.

When you go to remove an inner bogie-wheel, be sure to leave the hub-caps on throughout the job or you’ll have the wheel-bearings full of grime and grit before you know it—and we don’t have to remind you that spells woe. Another thing—if the outer bogie-tire is worn, you’ll be wise to change it before you start to change the inner bogie-wheel. Then you’ll have good clearance between the wheel and hull, and between the wheel and track on the inner wheel. Carry on.

M4 Tank Track Tools
Fig. 1—Here’s all the special tools you need to do either of these exercises: (A) Block, riser, bogie-wheel, Fed. Stock No. 41-B-1411-200 (before modification). (B) Block, riser, bogie-wheel, Fed. Stock No. 41-B-1411-200 (after modification). (C) Adapters, volute-spring removing, Fed. Stock No. 41-A-30-650. (D) Lock, riser-block, Ord. No. B-7080204. Any other tools you’ll use are OVM or common tools found on your M1 Heavy Wrecker.
HVSS Suspension M4 Tank, Figure 2
Fig. 2—To remove the volute spring, first loosen one wheel-bolt on each wheel of the bogie assembly involved. Place riser blocks, one in front of each wheel of the center bogie-assembly, and hunch the tank forward until the bogie-wheels center on the blocks as you see them here.

Continue reading Removing Inner Bogie Wheels on Horizontal-Volute Suspension

Take the “HE” Out of Summer’s Heat

“Take the ‘HE’ out of summer’s HEAT!” from Army Motors, Vol. 6, No. 3, June 1945.

Take the HE out of summer's HEAT!

Hot weather can stop your vehicle just as dead as a burst of hot steel—it takes a bit longer, that’s all. Summer-wise GI’s will bear down early and often on vital items like these:

  • COOLING SYSTEM—Drain antifreeze, flush system, install rust inhibitor. Check cylinder-head and filler-cap gaskets, thermostat, fan belt, pressure-relief valve, hose connections. Police up that radiator core. Look for leaks everywhere and always.
  • AIR CLEANERS—Keep elements clean—with solvent. Maintain proper oil level (if any).
  • FUEL FILTERS—Drain and clean element frequently.
  • MANIFOLD HEAT-CONTROL—Switch valve to summer position.
  • ENGINE—Wipe off heavy dirt and grease.
  • VALVES—Adjust timing and clearances with extra care.
  • BATTERIES—Watch electrolyte level. Water must be added more often in summer months.
  • TIRES—Keep air pressure what it should be. Check tires when they’re coolest—and don’t bleed them when they’re hot.

 

Watch on the Rhine

The nine main causes for failures of U.S. Army GMC trucks were outlined on the back cover of Army Motors, Dec. 1944.

Watch on the Rhine -- GMC Truck Repair and Maintenance

THE 1ST ARMY POINTS OUT 9 THINGS TO
WATCH ON THE RHINE

… or anywhere else 2½-ton, 6×6 GMC’s are taking a beating. Whenever overloads are authorized, wherever long hauls or tough terrain are everyday stuff, you’ll do well to double-check these items the nine “main causes of failures” reported by the 1st Army from the Western Front.

1. CHECK VALVE CLEARANCES: INTAKE .012, EXHAUST .016

2. ADJUST CLUTCH-PEDAL FREE TRAVEL (TO 2½”)

3. KEEP FOOT OFF CLUTCH PEDAL EXCEPT TO START, SHIFT AND STOP

4. DON’T TOW WITH JUST A ROPE OR CHAIN. USE TOW BAR TO PREVENT FRONT-END DAMAGE TO TOWED VEHICLE

5. TIGHTEN RADIATOR HOLD-DOWN BOLTS

6. TIGHTEN TRANSFER CASE, TRANSMISSION & PILLOW-BLOCK MOUNTING BOLTS

7. TIGHTEN CAB HOLD-DOWN BOLTS

8. CLEAN & RE-OIL HYDROVAC AIR CLEANER

9. TIGHTEN BOLTS THAT HOLD BOGIE ASSEMBLY TO FRAME

ALL THIS—AND THE REST OF FORM 461, TOO!