Paccar Kenworth T170 Hybrid 2011, Builder'S Manual

Page: 122 / 179

Section 7
Frame Modifications
7-2
12//11
See page 7-5 for more information on welding frames.
Do not drill new holes any closer than 2 inches (50 mm) to existing holes.
Frame drilling affects the strength of the rails and if not done properly
can cause the frame rails to fail and cause an accident.
A frame insert must be added after welding a frame rail extension to compensate for lost strength . The insert should be
of the same material as the frame member, or of steel, and at least equal to the frame rail in thickness . Attachment of the
insert to the frame should be made with Ream-Fit heat-treated bolts, 5/8 in . (16 mm) diameter or the next larger size . Both
the reinforcement and frame holes should be reamed to provide a fit of from .001 in. to .003 in. (.025 to .076 mm) clear -
ance . Do not weld reinforcing members . The insert should span a distance of at least 24 .21 in . (615 mm) on either side of
the crack to ensure an even distribution of stresses. Cut the ends of the insert at 45° as shown in Figure 7–2 unless the
insert extends to the end of the frame .
FIGURE 7-1. Detail of Frame
Extension and Joint Welding
Frame Insert
MODIFYING FRAME LENGTH
The frame cutoff after the rear axle can be shortened to match a particular body length . Using a torch is acceptable;
however, heat from a torch will affect the material characteristics of the frame rail. The affected material will normally be
confined to within 1 to 2 inches (25 to 50 mm) of the flame cut and may not adversely affect the strength of the chassis or
body installation .
The frame cutoff can be lengthened by adding frame extenders .
When extending 10 .5” frame rails, the additional sections can be welded to the existing rails . The joint should be welded
and reinforced as illustrated in Figure 7–1 .
24 .21 Inch
Minimum
(615 mm)
WELDED
JOINT
Note:
WARNING:
FIGURE 7-2. Frame Insert