SECTION IV. WELDING OF 5-TON VEHICLE FRAMES

TB 9-2300-247-40

(6) Forming cracks generate at sharp radius when

(7) Length of crack does not exceed 1-inch.

originally formed are detectable only on one side.

Flanges with cracks exceeding 1-inch will be removed for

welding repair as shown in Figure 39.

SECTION IV. WELDING OF 5-TON VEHICLE FRAMES

For tractors, remove fifth wheel, fifth wheel

NOTE

anchor bolts, dump bed, and hydraulic hoist, as

required.

The M939 vehicle series have heat-

treated frames and will not be

g. For cargo trucks, remove cargo body brackets,

repaired by welding.

wooden sills, as applicable, remove anchor

bolts, and raise body for clearance.

50.

General.

5-ton vehicle frames generally

experience cracks at several common locations of both

h. Remove all electrical harnesses, fuel and

the left and the right frame rails, at: (1) the trapezoidal

hydraulic lines, and related items as required for

plate, (2) bogie support bracket, intermediate

access to the area of repair. Take care to

crossmembers, and the forward jounce brackets on the

preserve the integrity of all components removed

lower flange.

Repairs to these areas may be

for future installation.

accomplished by special reinforcement plates, angles,

and reinforcing doubler plates of various types. The

Sketches. Prepare sketches to design specific

welding repairs covered here will not include all possible

repair requirements as required and/or as shown

defects or frame conditions but relies on the experience

in this section.

and ingenuity of repair personnel in the use of this

information.

Where required, jack up and evenly support the

vehicle frame to gain access to the area to be

51.

Preliminary Procedures. Perform the following

repaired. Provide firm support on each side of

preliminary procedures:

the defect or the area to be repaired to reduce

any stress on framing members to a minimum.

a. Thoroughly clean vehicle frame o f all, oil,

grease, dirt, paint, asphalt, and debris.

Thoroughly clean all frame rails and supporting

members of dirt, asphalt, paint, etc.

b. Perform general vehicle frame inspection as

specified in Chapter 1.

Once crack has been detected, measure crack

with crack limit gage (Figure 2) by placing gage

Perform vehicle frame alignment inspection as

on top of frame over the crack. Crack should not

specified in Chapter 3.

exceed 1-1/2-inches.

d. Remove all necessary components/assemblies

m. Using center punch, mark location of crack at

as required for accessibility:

the extreme end of the crack.

WARNING

n. Defect. Forming Cracks On Radius Of Front

Crossmember Flanges (Figure 39).

Use only effective chip guarding

equipment, protective equipment and

52. Defect Description.

The radius of front

protective clothing (goggles, shields,

crossmember flanges which have forming cracks on the

gloves aprons, etc) when doing any

internal side of radius, which extend longitudinally

drilling, grinding, or welding. Failure

through radius.

to follow this warning could result in

injury to personnel.

53.

Repair Procedure.

a. If crack extends only partly through section, drill

e. Remove bolts and rivets securing securing

3/16-inch diameter at end of crack to minimize

brackets or other items to the frame as

the tendency to increase.

described in Chapter 1.