Turn the ignition switch on for no longer than
five seconds. The ABS indicator lamp will be
on.

11

No speed failure

12

Control pressure failure

1) Turn the ignition switch off. The ABS
indicator lamp will go out.

13

Supply pressure failure

2) Turn the ignition switch on. The ABS
indicator lamp will then come on, then go
out.

14

Power supply failure

15

ECU internal failure*

16

SAE J 1708 failure

3) The blink code error will be displayed
three times by the ABS indicator lamp on
the trailer.

17

PLC failure

18

Generic IO failure

19

Load sensing failure

20

Roll stability system failure

57

WHEEL BEARINGS & SEALS
The wheel hub revolves around the axle spindle on two roller bearings. The
bearings are lubricated and the hub cavity is sealed against leakage by a seal
which rides around an axle ring on the spindle shoulder. Figure 14 illustrates
the bearing and seal arrangement.
Check oil level and for leaks around the oil seal at least once a week. If low,
refill hub to oil level line on hub cap. Heil Trailer International, Co. uses
75W90 Synthetic Gear Oil. For best results and wheel end life, use only
compatible lubricant products.

Figure 14. Cross Section View of Wheel Hub

Wheel Bearing Adjustment
Bearing adjustment should be 0.001”-0.005” end play and a minimum of
pre-load. Use the following procedure:
1. Tighten inner jam nut (Figure 14) with a 12 inch wrench while
turning wheel in both directions until there is a slight bind which
indicates all bearing surfaces are in contact.

58

Wheel Bearing Adjustment (continued)
2. Back off inner jam nut 1/3 turn to allow the wheel to rotate freely.
3. Install washer and tighten outer jam nut.
4. Final bearing adjustment should be with 0.001” to 0.005” end play.
Tighten nuts at this position.

Figure 15. End Play Adjustment

Oil Seal Replacement
If oil leakage around the inner oil seal is noted, replace the oil seal (and axle
ring, if required) as follows:
1. Remove wheels and hub.
2. Remove and discard old seal.
3. Inspect axle ring. If pitted or worn, replace as follows:
a. Remove old ring. Take care not to damage spindle.
b. Clean spindle thoroughly. Shoulder area must be smooth and free
from weld spatter and burrs.
c. If shoulder is not completely smooth apply sealer No. 2 to correct
any defects and ensure an oil-tight fit.

59

Oil Seal Replacement (continued)
d. Using axle tool, drive the axle ring firmly on shoulder. Edge of
axle ring must be parallel and flush with shoulder face.
Remove excess sealer, if used.
4. Install oil seal in wheel hub as follows:
a. Remove all burrs from inside hub bore.
b. If seal is not pre-coated with BLU-SEAL, or if wheel hub bore
is not entirely free of nicks or burrs, apply a thin coat of sealer
No. 2 to the O.D. perimeter of the oil seal.
c. Lay wheel down, brake drum up. Check to ensure that hub
cavity is clear of old grease, grit and metal particles-steam clean
if possible. Check bearing cones on spindle for proper slip fit.
Install inner bearing in hub bore. Place seal in starting position
in bore.
d. Using hub tool and a hammer, drive seal squarely and evenly
into bore. Seal should bottom evenly all around against bearing
cup. DO NOT continue to hammer after seal has bottomed
evenly, as damage to the seal will result.
5. Coat seal lip and inside diameter of inner bearing cone, then install
wheel on axle. Take care not to damage seal during installation. If
wheel does not slip back in place easily, remove and check for burrs
or possible component damage.
6. Install outer bearing, jam nuts and washer. Adjust bearing preload
(see Wheel Bearing Adjustment).
7. Install gasket and hub cap.
8. Refill hub with recommended oil. See Wheel Bearings and Seals. 1
to 1-1/2 pints are required per hub, depending on wheel well design.
A minimum of 1 pint is required for proper lubrication. Allow plenty of
time for the oil to seep through the bearings.
9. Re-install vent plug.

60

WHEEL & TIRE MAINTENANCE
Proper tire inflation and correct installation of rims and wheels is essential to
safe, economical, trouble-free service.
Check tire pressures daily. Recommended inflation pressure is noted on VIN
Data Plate. DO NOT over-inflate tires, as this is a common cause of rim failures
and accidents. Never run vehicle on one tire of a dual wheel assembly. Loss of
air in one tire of a dual set excessively overloads the other tire if the vehicle is
operated in this condition.
When checking tire pressures, visually check studs and rim for looseness, cracks
or other damage. Inspect tires for uneven wear, cuts, cracks, etc., which would
render the tire unfit for further service. If the least doubt exists as to the tires’
serviceability, replace the tire.
Check wheel lug torques at least once a week. See Page 71 for recommended
lug nut torques.

DANGER
Be extremely careful when working with tires and wheels. Tires and
wheels can come apart with explosive force. Never attempt to
disassemble a wheel with an inflated tire mounted on it.

61

NOTICE
Insufficient mounting torque can cause rim slip, resulting in broken
valves, worn parts and damaged tires. Excessive mounting torque can
cause damage by stripping studs, collapsing spacer bands or forcing
rims into an out-of round condition.

Figure 16. Disc Wheel Installation

Recommended Installation Procedure-Disc Wheels
1. Check all parts for damage, including wheels and rings. Insure that all studs,
nuts and mounting faces of hub and wheels are clean and free from grease.
Replace any defective parts.
2. Mount inner dual wheel over studs, being careful not to damage stud
threads.
3. Mount the outer wheel, being careful not to damage stud threads and hand
tighten wheel nuts.
4. Tighten nuts fully, using a crossing pattern as shown above in (Figure 16).
Be sure to tighten nuts only to the recommended torque. For correct wheel
lug nut torque see page 71.

62

AXLE ALIGNMENT
NOTICE
Insufficient mounting torque can cause wheel shimmy, resulting in
damage to parts and extreme tire tread wear. Excessive mounting
torque can cause studs to break and discs to crack in the stud hole area.

Improper axle alignment will cause dog-tracking and excessive tire wear. To
check alignment of axles to king pin, use the following procedure:
1. Set empty trailer on level smooth surface, disconnect trailer brakes and
bleed air tank.
2. Rock trailer back and forth for a distance of approximately 10 feet to relieve
any binding in brakes or suspension bushings.
3. Tow trailer straight forward for a distance of approximately 30 feet. Stop
trailer with tractor gears or tractor brakes only.
4. Disconnect tractor from trailer and ensure suspension ride height is properly
adjusted.
5. Adjust landing legs to level trailer and set upper coupler to the correct ride
height.
6. Do not remove wheels, but remove all hub caps and install axle center
extensions. Use suitable kingpin jack or center extension to insure a clear
path from the kingpin centerline to the axle center extensions.
7.

Measure from kingpin extensions to both front axle center extensions. This
distance should be the same on both sides (A = B).

8.

If not, remove and install new pivot bolts leaving them loose enough to
adjust axle to square with the kingpin. Make sure there are no obstacles in
front of wheels during alignment.

Notice
Pivot bolts must be replaced during realignment of the suspension.

63

Axle Alignment (continued)
9.

Measure from front axle center extensions to rear axle center extensions.
This distance should be the same of both sides (C = D). If not, remove and
install new pivot bolts leaving them loose enough to adjust rear axle to
parallel with front axle. The suspension should now be in proper alignment
with the kingpin.

Figure 17. Trailer Alignment

10. The QUIK-ALIGN® style pivot connection uses two flanged collars inserted
into slots on each side of the frame bracket (Figure 19). The eccentric collar
on the outboard side of the frame bracket is used to adjust the position of
the axle during an alignment. The alignment guides on the side of the frame
bracket limit the eccentric collar to rotational movement in the frame bracket
slot. Rotating the eccentric collar clockwise causes the axle to move forward.
Rotating the eccentric collar counterclockwise causes the axle to move
rearward (Figure 18). The maximum range of adjustment is ±45 degrees
from the 12 o’clock position.

64

Figure 18. Quick-Align Operation
11. Using an E20 Torx socket, tighten the shear-type bolt axle pivot connection
until the Torx head shears off. This ensures the proper torque of 550 ft. lbs.
(±45 ft. lbs.). Pivot bolts must be replaced when trailer is aligned. DO NOT
attempt to reuse old pivot bolts. Assembly of pivot connection shown below
(Figure 19).

Figure 19. Pivot Connection Assembly
12. Connect tractor to trailer and connect trailer brakes on the lot. Make four or
five tight figure eights and an equal number of “panic” brake stops. Bring
trailer back into shop and check axle alignment. If axles are not in proper
alignment, check for loose or worn bushings and bearings, loose or broken
hangers, cross members, side rails or kingpin.

65

LIFT AXLE ALIGNMENT
LIFT AXLE ALIGNMENT
Following the procedures below will provide the proper axle alignment.
Note: Does not apply to units that are pre-aligned.
1. With chassis on a flat level surface set suspension at the proper ride height
with no load. Block tires on truck chassis and release brakes on auxiliary
axle. This will allow tire rotation while positioning the suspension fore and
aft.
2. Position one beam of the auxiliary suspension so the alignment collar is in
the center of the alignment slot and tack weld the alignment collar to frame
bracket side place.
3. Measure from the truck chassis front drive axle (or rear drive axle for tag
type axle) to the top of kingpin housing (common point on both sides of
axle). Move the free beam fore or aft until both sides are equal distance to
drive spindle. A total maximum alignment tolerance of 1/8” is considered
acceptable. If additional axle movement is required remove tack weld and
adjust axle as required.

Figure 20. Alignment

NOTE: For more information reference the manufactures web literature or call
their customer support.

66

Trailer Suspension System
Components and General Maintenance Guidelines
HEIGHT CONTROL VALVE - The height control valve on the trailer air suspension automatically responds to the relative position of the axle and vehicle frame.
It meters air into or out of the air springs. Variations in load or temperature only
affect the adding or exhausting of air. The trailer air suspension is a mechanically
stable suspension, only one height control valve is necessary.

Figure 21. Suspension Height Control Valve

When the actuating lever of the height control valve moves up, the valve opens
and connects the air supply to the air spring. When the actuating lever moves
down, the valve shuts off the air supply and opens the exhaust port to vent
excess air from the air springs. A check valve prevents the loss of air spring
pressure if the air supply fails. In the central position, air does not flow in or out
of the air springs.
Notice
When adjusting the height control valve, block the tires and release the
trailer brakes. The axle must rotate freely to avoid a false reading.
Some height control valves have very small openings and a time delay
of as much as 15 seconds. Allow sufficient time for the system to react
to the adjustment. The response time will appear to be lengthy, but be
patient.

67

Trailer Suspension System
Components and General Maintenance Guidelines

The ride height can also be found on the suspensions ID tag located on the
inside of the curbside beam (Figure 22).

Figure 22. Suspension ID Tag
RIDE HEIGHT ADJUSTMENT
1. Connect the vehicle to a compressed air supply with approximately the
pressure of the normal supply system.
2. Ensure the inflation of the air springs.
3. Measure the ride height by using this method:
a. Measure from the underside of the trailer frame to the top of the
axle as shown below (Figure 23).
b. Add half the diameter of the axle to the measurement.

Figure 23. Ride Height Measurement
4. Raise or lower the trailer as necessary, so it is at the designed ride height.
5. Once the trailer is set to the correct designed ride height, set the HCV lever to
the neutral (central) position.

68

Trailer Suspension System
Components and General Maintenance Guidelines
6. Adjust the HCV linkage to fit between HCV lever and lower linkage
attachment.
7. Once set to the designed ride height, test drive the trailer. After the test
drive, check the ride height to assure an accurate adjustment.
AIR SPRINGS - Air springs will last almost indefinitely in most applications.
However air springs will fail quickly when rubbed, scuffed, or punctured. If an air
spring fails, the trailer will settle on the internal rubber bumpers, so you can
proceed to the nearest service facility at a lower speed. You should try to
determine the cause of a failure, so you can avoid a costly repeat of the
problem.

Air Spring Replacement
To replace an air spring, follow these steps:
1.
2.
3.
4.
5.
6.
7.
8.
9.

Exhaust all air from the suspension system.
Raise and support the vehicle in a safe manner.
Unbolt the air spring.
Disconnect air-supply lines.
Replace the air spring.
Bolt the air spring in place.
Connect the air-supply lines.
Lower the trailer to the ground.
Supply air to the suspension system.

SHOCK ABSORBER - Shock absorbers absorb energy to prevent suspension
oscillation. Shock absorbers are also rebound stops in most air suspensions. The
shock absorber limits the stroke of an air spring, which prevents the air spring
from being pulled apart.
To remove a shock absorber, follow these steps:
1.
2.
3.
4.

Remove the end fasteners.
Insert the new shock absorber.
Secure with correct size locknut and bolts.
Torque fasteners to specification.

69

Trailer Suspension System
Components and General Maintenance Guidelines

PIVOT CONNECTION - A correct pivot connection is crucial to the life
of the suspension. The pivot fastener must continually provide a
sufficient clamp load through the bushing to prevent premature suspension failure. Hendrickson INTRAAX suspension systems come equipped
with QUIK-ALIGN pivot connection hardware. The hardware consists of a
specially plated shear bolt to ensure a proper clamp load, (550 ft-lbs, H45 torque).
NOTICE
Failure to properly torque the pivot bolts may result in loss of
warranty coverage.

TRI-FUNCTIONAL BUSHING - have unique properties that will provide
years of maintenance-free service. The TRI-FUNCTIONAL BUSHING
(located at the suspension pivot connection) provides a resilient connection that allows an axle to walk without excessive flexing. The TRIFUNCTIONAL BUSHING, in conjunction with the rigid axle connection,
results in a roll-stable suspension design that resists trailer lean
independent of the air spring loading. Reference Hendrickson service
guide L427 for bushing replacement procedures.

Figure 24. Pivot Connection Assembly

70

TORQUE SPECIFICATIONS
RECOMMENDED SUSPENSION TORQUE

RECOMMENDED WHEEL TORQUES

71

Notes:
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72

REPORTING SAFETY DEFECTS
If you believe that your vehicle has a defect which could
cause a crash or could cause injury or death, you should
immediately inform the National Highway Traffic Safety
Administration (NHTSA) in addition to notifying Heil Trailer
International, Co.
If NHTSA receives similar complaints, it may open an investigation, and if it finds that a safety defect exists in a
group of vehicles, it may order a recall and remedy campaign. However, NHTSA cannot become involved in individual problems between you, your dealer or Heil Trailer
International, Co.
To contact NHTSA, you may either call the Auto Safety Hotline toll-free at Monday-Friday 8am to 8pm at (888) 3274236 , TTY: (800) 424-9153, or file an online form at
www.nhtsa.gov. You can also obtain other information
about motor vehicle safety from the Hotline.

73

CORPORATE OFFICE
Heil Trailer International, Co.
1850 Executive Park Drive N.W.
Cleveland, TN 37312
Phone: (423) 745-5830

MANUFACTURING PLANTS
Heil Trailer Athens

Heil Trailer Texas

1125 Congress Pkwy.

500 Randall Street

Athens, TN 37303

Rhome, TX 76078

Phone: (423) 745-5830

Phone:(817) 636-2201

Heil Asia, Limited

Heil Trailer Internacional, S.A.

168, Moo 16 Udomsorayut Rd.

Ruta 3 Km. 66,300

Bang Gra-san, Bang Pa-in

(1814)Cañuelas

Ayutthaya 13160, Thailand

Buenos Aires, Argentina

[66] 35221090 Ext. 110

[54 2226] 431810

PARTS AND SERVICE
Heil Tank Service
3808 Bells Lane
Louisville, KY 40211
Phone: 800-428-0288

Heil Part Number: 9544-0010
74