Self-Centering Alignment Gauges; Center Line And Datum Line; Frame Alignment; Frame Conditions - Jeep 1987 Wrangler Workshop Manual

WELDED COMPONENTS
BODY REPAIR INFORMATION
SELF-CENTERING ALIGNMENT GAUGES
Alignment gauges show misalignment by pro-
jecting alignment points of the frame into a line-
of-sight that can be read by the technican. A
through understanding of the information
shown by the gauges will enable the technican
to diagnos damage and misalignment quickly
and accurately.
Gauges have two sliding horizontal bars which
remain parallel as they move inward and out-
ward. This inward or outward action permits
adjustment to any width for installation on vari-
ous areas of the vehicle. Once the gauges are
hung in place, the horizontal bars will be parallel
to that portion of the frame that they are at-
tached. This permits the technican to "read"
that area relative to an adjacent area.
Gauges are equipped with center pins that are
designed to remain in the center of the gauge
regardless of the width of the horizontal bar.
This allows for a true centerline throughout the
length of the vehicle.
Each gauge accommodates two vertical scales.
These scales can be adjusted vertically to as-
sure that the horizontal bars accurately reflect
the true position of the parts to which they are
attached. This allows all structional misalign-
ments to be read - centerline, level and datum.
CENTER LINE AND DATUM LINE
Before laying out a mechanical drawing, it is
necessary for the drafter to establish a refer-
ence line from which to start. This is accom-
plished by establishing a centerline or a datum
line. In fact the centerline or datum line will exist
only on paper.
Consequently, when installing gauges, it is sim-
ply a matter of using the reference points and
measurements to establish proper gauge
heights or location.
FRAME ALIGNMENT
Before any attempt is made to read the frame
alignment gauges, it is important that the
technician fully understand the definition of
correct alignment.
Structural alignment gauges should be installed
in such a way that the line of sight reading can
easily be read by the technican.
If the gauges are installed properly on a straight
frame, all gauges will be parallel, on the same
plane and the center pins will align.
Also rember that correct frame alignment must
include correct length and width measurements
through the entire frame.
FRAME CONDITIONS
The following examples are of sight pin align-
ment using the self-centering gauges.
Front Side Sway
1
1
S E E
I.S.
N
O
T
E
S
REAR O F VEHICLE
101407
S- 17