User's Manual

Date of Origin – 02/01/08

AXLE ALIGNMENT

Proper axle alignment is a vital part of trailer maintenance. Failure to maintain proper alignment

may cause tire scrubbing and suspension component strain. Your trailer’s alignment should be

checked regularly and the axles realigned when required to prevent unnecessary tire wear.

1. To properly align the suspension make sure the trailer is unloaded. Free the suspension of

any “binds” by first pushing the trailer backwards and then pulling it forward a sufficient

distance. Check axle alignment with the trailer on a level surface with the trailer level both

side to side and front to back, with tires properly inflated, trailer securely restrained, trailer

brakes (service & parking) released and with the trailer ride height valve properly set (if an

air ride).

2. Check each dual tire set. Tires of each set must be matched to a maximum of 1/8” tire

radius. Air pressure must be the same in all tires.

3. Using a steel measuring tape, measure from the center point on the bottom of the king pin

to identical locations on each end of the front axle using a consistent amount of pressure on

the tape measure.

4. If these measurements differ by more than 1/16”, adjust one end of the front axle forward or

rearward until identical measurements are obtained on both ends.

5. After the front axle is aligned and secured, measure from the end of the front axle to the end

of the rear axle on each side.

6. If these measurements differ by more than 1/16”, adjust one end of the rear axle forward or

rearward until identical measurements are obtained on both ends.

Spring suspensions are equipped with screw adjusted torque arms located on the driver’s left

side of the trailer. Adjustment of the alignment is accomplished by turning the torque arm in or out,

depending on the adjustment required.

1. Loosen the radius rod clamp bolts.

2. Move the left end of the axle forward (shorten the alignment measurement) by turning the

torque arm to make it shorter.

Move the left end of the axle rearward (lengthen the alignment measurement) by turning the

torque arm to make it longer.

3. Check the alignment measurements. Repeat the adjustment in Step #2 as necessary.

4. When the axle is correctly aligned, tighten the radius rod clamp bolts to 130 ft. lbs. oiled or

170 ft. lbs. dry.

Note: Check the clamp bolt torque within the first 50 to 100 miles of operation following align-

ment.

Air ride suspensions are equipped with mechanisms to allow the movement of one end of the axle

forward or rearward for the purpose of aligning the trailer axles.

Inspect the hanger pivot bushings as well as all other suspension components before adjusting the

alignment.