Alignment & Adjustments; Drive Axle Alignment Inspection Procedure - ProGear Hendrickson HN FR Series Service Manual

HN ® FR Series
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
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
6. Ensure all drive axle tires are the same size.
7. Securely clamp a six-foot piece of
8. Accurately square the bar stock or
9. Using a measuring tape, measure
10. Calculate the difference between measurements
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.
Alignment & Adjustments
Pro Gear and Transmission • 906 W. Gore St. Orlando, FL 32805 • 1 (877) 776-4600 / (407) 872-1901 • parts@eprogear.com
line without using the brakes. This will slacken or loosen the suspension as the vehicle is
positioned. End with all wheels positioned straight ahead.
damaged suspension components before proceeding with the alignment process.
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.
angle iron to the frame using a car-
penter's square.
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.
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.
18
FIGURE 7-1
A and B.
17730-285