1993 DODGE TRUCK Service Repair Manual

Fig. 4 AD4 Frame Structure

RIVETS EXCEPT AS NOTED

PU893B

Fig.
5
ADS,
6 & 7 Frame Structure

FRAME
AND
BUMPERS
13 - 25
FUNCTION
The frame is the foundation and the structural cen­
ter of the vehicle. The primary function of a frame is
to provide support and attachment locations: • For all the chassis/drivetrain components
• For the cab/body
• For the vehicle payload While limiting deflections and twisting of the
frame members. The frame maintains the correct relationship and
alignment of the powertrain. This relationship and
alignment ensures normal operation of the attached

units.

CONSTRUCTION MATERIAL High-strength, carbon steel with a minimum yield
strength of 32,000 psi is used to construct frame side

rails.
A frame made of 32,000 psi minimum yield
strength steel has, in reality, a range of 32,000 to
44,000 psi yield strength.
For 4WD vehicle applications, the frame side rails
reinforcements are constructed of the same high- strength, carbon steel as the side rails.
BENDING RESISTANCE A frame reacts to its load and the road surface de­
viations by deflecting and twisting. The primary de­
flecting frame members are the side rails. Resistance
to frame twist is provided by the crossmembers.

FRAME
INSPECTION/MEASUREMENTS

INSPECTION Inspect the frame members for visible damage and
metal deformations. Inspect all riveted, bolted and
welded connections for looseness and/or missing hardware. All damaged areas must be repaired and/or the
frame members replaced, as necessary.
MEASUREMENTS Measure the frame for mis-alignment with the cab/
body and cargo box attached to the frame. Figures 7, 8, 9 provide the frame alignment reference dimen­

sions.

The following information applies to all measure­
ments.
(1) Place the vehicle on a level surface.
(2) If the vehicle is loaded, verify the vehicle does
not exceed the gross vehicle weight rating (GVWR).
Verify the load is distributed in the vehicle as evenly as possible. For better measurement results, remove
the cargo/payload from the vehicle.
(3) Measure the tire inflation pressures. Adjust as
necessary.
HORIZONTAL/DIAGONAL
FRAME MEASUREMENTS

Determine the frame horizontal, according to the
following procedure.
(1) Select several reference points along one frame
side rail, preferably at the crossmember junctions.
(2) Transfer these reference points to the surface/
floor. Paper sheets can be attached to the surface be­ low the reference points.
(3) Locate the same reference points on the other
frame side rail. Transfer them to the surface/floor.
(4) Move the vehicle away. Measure between all
the reference points diagonally from and parallel to
the side rails (Fig. 10). The corresponding measure­ ments should not differ by more than 6 mm (1/4 in).

(5)
Measure the distance between the two front
reference points. Measure the distance between the
two rear reference points. Divide each distance in
half and indicate the two half-way points on the sur­
face/floor. Designate the front point as 1 and the rear
point as 2 (Fig. 10).
(6) Place a chalk-line between points 1 and 2 (Fig.
10) and snap the string.
(7) Determine how close the center line is to the
diagonal intersection points in Figure 10.
(8) The marks on the floor will show the amount of
frame misalignment.
(9) The reference point transferred from one side
rail should be within 3 mm (1/8 in) of the opposite
reference point.
(10) Frame bow to the side should not exceed 3
mm per 2540 mm (1/8 inch per 100 inches) in frame
length.
(11) The overall width of the frame should not
vary more than 3 mm (1/8 in). (12) Repeat steps (1) through (11) after straighten­
ing the frame.
Refer to Figures 7, 8, and 9 for frame horizon­
tal alignment reference dimensions.

TWIST
AND PARALLEL FRAME MEASUREMENTS
Determine the amount of frame twist using the fol­
lowing procedure.
(1) Mark the vertical reference points under the
frame side rails at 305-mm (12-in) intervals. Start at
the rear frame crossmember.
(2) Measure the distance up from a level surface/
floor to each corresponding reference point. (3) The distance to a reference point under one
side rail should be a maximum of 3 mm (1/8 in)
dif­

ference than the opposite side rail.
Refer to Figures 7, 8 and 9 for frame vertical
alignment reference dimensions.

TO OUTSIDE
OF
METAL

INSIDE
OF
METAL

37.68

CENTERLINE
OF
FRONT
WHEELS
750
DIAMETER GAUGE HOLE 5.55

REAR
OVERHANG

'SEE
SPECIFICATIONS"
Fig. 7
Frame
Dimensions—AD1, 2 & 3
mm

•
FRAME
AND BUMPERS 13 - 27

RN888

Fig.
10 Frame Horizontal
Aligi
FRAME
REPAIR

GENERAL
INFORMATION
Frames that are either bent or twisted can be
straightened by application of heat, The temperature
must not exceed 566°C/1050°F (a dull red glow). Ex­
cessive heat will decrease the strength of the metal.
This will result in a weakened frame.
Damaged frame side rails, crossmembers, and
brackets are repaired either by straightening them or by replacement.
Welding joints between the frame side rails and
crossmembers are not recommended.

FRAME MEMBER
STRAIGHTENING
A straightening repair process should be limited to
frame members that are not severely damaged. The
hardware that is used to join the frame members should conform to the same specifications as the orig­

inals.

FRAME MEMBER
REPLACEMENT Frame member replacement is recommended if the
shape is not recognizable.

FRAME
MEMBER REPAIRS

DRILLING
HOLES
Holes should not be drilled in frame side rail
flanges. This will reduce the frame strength. ent Reference Points—Typical

WELDING
It is recommended that electric welding equipment
be used to weld frame side rails and crossmembers. This method imparts heat only to a small area.
A damaged frame member should be examined for
hairline cracks. Repair frame member cracks accord­ ing to the following procedure.
(1) Stop-drill a hole at each end of the crack with a
3-mm (1/8-in) diameter drill bit.
(2) V-groove the crack to allow good weld penetra­
tion. (3) Weld the crack.
(4) Grind the weld surface area smooth. Install a
reinforcement section at the welded area. The flanges on reinforcement channel, should
not exceed the width of the side rail flanges.
This will avoid the necessity of welding along
the outer edge of the side rail flanges. Longitu­ dinal welds are acceptable. Transverse welds
must be avoided.

FRAME REPAIR HARDWARE
Bolts,
nuts and rivets can be used to repair frames.
When it is necessary to use a bolt for a rivet, install
the next-larger-size diameter bolt. This will prevent
the bolt from loosening. Ream the hole to fit the bolt.
Conical-type lockwashers are preferred over the
split-ring type lockwashers.Grade-3 bolts (or less) should not be used. Tightening bolts/nuts with the
correct torque is mandatory to prevent them from
loosening.

REINFORCEMENT SECTIONS
A reinforcement section must overlap beyond the
repair area. A reinforcement section can be cut from channel steel, angle steel, or flat stock steel. Com­
mon carbon steel that is equal in thickness to the
frame member is acceptable.