Paccar Kenworth T680 2019, Manual

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8-3
2/17
Section 8
Frame Modifications
FIGURE 8-2. Frame Insert
Where possible, use existing bolt holes to attach the insert to the frame. Bolt holes must not be located closer to the frame
flanges than the present bolt pattern.
If the insert is placed in a section of the main frame where few bolts are located, additional bolts are required. Use the fol-
lowing guideline for locating additional bolt holes.
CHANGING WHEELBASE
We do not recommend modifying the wheelbase. Occasionally, however, a chassis wheelbase will need to be reduced or
lengthened. When this needs to be done there are a few guidelines that should to be considered.
When changing the wheelbase, be sure to follow the driveline manufacturer’s recom-
mendations for driveline length or angle changes. Incorrectly modified drivelines can fail
prematurely due to excessive vibration.
Before changing the wheelbase the driveline angles of the proposed wheelbase need to be examined to ensure that no
harmful vibrations are created. Consult the driveline manufacturer for appropriate recommendations.
When changing the wheelbase, a continuous blank frame insert/outsert must be added in
the area of the new rear suspension mounting bolts. All new mounting holes must pass
through the original rail and the insert/outsert. Failure to do so could cause excessive
stress in the original rail due to additional holes.
Before the rear suspension is relocated, check the new location of the spring hanger brackets. The new holes for the
spring hanger brackets must not overlap existing holes and should not come any closer than 2 inches (50 mm) to existing
holes in the frame.
When relocating a suspension bracket, do not mount it on the extended (added) section of
a frame rail. The suspension loading could result in premature failure of the added section
splice. This could cause an accident. Use care when planning the wheelbase so that the
rear suspension bracket is always mounted on the original rail section. See Figure 7–3.
24 Inch
Minimum
(610 mm)
WARNING!
WARNING!
WARNING!
WELDED
JOINT