
HN
®
FR Series
Alignment & Adjustments
18
17730-285
SECTION 7
Alignment & Adjustments
DRIVE AXLE ALIGNMENT INSPECTION PROCEDURE
Proper alignment is essential for maximum ride quality, performance, and tire service life. The
following recommended alignment procedure as described below, should be performed if
excessive or irregular tire wear is observed.
NOTE
Proper vehicle alignment can only be achieved when all axles are aligned to the vehicle’s
centerline and the steering axle’s caster, camber and toe-in settings are within specifications.
If, however, axle alignment equipment is not available the alignment of the drive axles may be
checked by performing the following steps.
1. Use a work bay with a level, flat surface.
2. Relax the suspension by slowly moving the vehicle back and forth several times in a straight
line without using the brakes. This will slacken or loosen the suspension as the vehicle is
positioned. End with all wheels positioned straight ahead.
3.
DO NOT
set the parking brake. Chock the front wheels of the vehicle.
4. Verify and maintain the air system at full operating pressure.
5. Verify all suspension components are in good condition. Repair or replace any worn or
damaged suspension components before proceeding with the alignment process.
6. Ensure all drive axle tires are the same size.
FIGURE
7-1
7. Securely clamp a six-foot piece of
STRAIGHT bar stock or angle iron
across the lower frame flange as
shown in Figure 7-1. Select a loca-
tion for the bar stock or angle iron
as far forward of the drive axle as
possible where components will not
interfere.
8. Accurately square the bar stock or
angle iron to the frame using a car-
penter’s square.
9. Using a measuring tape, measure
from the straight edge to the forward
face of the front drive axle arms on
both sides of the vehicle as shown in
Figure 7-1,
A
and
B
.
10. Calculate the difference between measurements
A
and
B
.
a. If the front drive axle is within vehicle manufacturer’s specifications, proceed to check
the rear drive axle (Step 11).
b. If alignment of the front drive axle
IS NOT
within the vehicle manufacturer’s specifica-
tions, then the alignment of this axle
MUST
be corrected
BEFORE
measuring the rear
drive axle alignment (Step 11). Correct the alignment of this axle by following the bar
pin alignment instructions.
NOTE
Since the remaining drive axle will be aligned relative to the front drive axle, it is essential
that the front drive axle is aligned within the vehicle manufacturer’s specifications prior to the
alignment of the remaining drive axle.
Pro Gear and Transmission • 906 W. Gore St. Orlando, FL 32805 • 1 (877) 776-4600 / (407) 872-1901 • [email protected]