Lufkin Dump Trailer User manual

DUMP TRAILER
OWNER’S MANUAL
LUFKIN INDUSTRIES, INC.
P.O. BOX 849
LUFKIN, TX 75902-0849
800-324-3812

Page 2
INTRODUCTION
This manual is provided to every user of a newly manufactured LUFKIN trailer to acquaint you
with the importance of maintenance and safety in the operation of your trailer.
The life of a trailer can be increased with adequate regular service and an organized Trailer
Preventative Maintenance program (TPM). The Department of Transportation requires by
regulation that maintenance records be kept on every commercial highway vehicle. It is to your
advantage to be able to show that regularly scheduled TPM inspection checks have been
performed on every piece of equipment operated and will place you in the most favorable
position from a legal standpoint in the event of an accident involving your equipment.
If LUFKIN can be of help in your Trailer Preventative Maintenance program, please give us a
call.
LUFKIN INDUSTRIES, INC.
IMPORTANT NOTICE
Vehicles manufactured by LUFKIN INDUSTRIES, INC., are designed to be operated in
accordance with the gross axle weight rating (GAWR) shown on the certification label and at
legal highway speeds in the service for which they were intended.
GENERAL INFORMATION
Maintenance should be performed by a LUFKIN Dealer or by other qualified service facilities
that regularly provide such service.
Alterations to a LUFKIN Trailer should not be made without first consulting the LUFKIN Trailer
Engineering Department. Alterations could affect the structural integrity of the trailer and void
the warranty. Welding or other alterations should never be made to any air reservoir, wheel,
rim, air chamber, or spring.
The gross axle weight rating (GAWR) that is stamped on the certification plate is the structural
capacity of the lowest rated component of the suspension, springs, hubs, drums, wheels, rims,
bearings, brakes, axles, or tires.
If components are substituted that affect GAWR that are of less capacity that those originally
installed, the GAWR on the certification plate must be lowered to the corresponding lower
capacity by adding an “Altered Vehicle” label. If components are substituted that are of equal
or greater capacity than those originally installed, then GAWR labels need not be changed.
Appearance maintenance is important to the Trucking Industry. It can favorably project the
public image of your company. It also adds to their physical condition and ultimate trade-in
value.
Protective films such as paints and other coatings are necessary to prevent corrosion and
protect the metal and wood surfaces. Trailers that operate in environments that are conducive
to severe corrosion may require more or different protective coatings than those usually
applied as standard; check with your LUFKIN representative for recommendations.
There are “WARNING” and “CAUTION” decals prominently displayed on all trailers. All
personnel operating the vehicle should follow these.

Page 3
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 LUFKIN Trailers warranty or engineering departments at the numbers below.
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 LUFKIN Trailers.
To contact NHTSA, you may either call the Auto Safety Hotline toll-free at 1-888-327-4236 (TTY: 1-800-
424-9153) or write to National Highway Traffic Safety Administration, 400 Seventh Street, SW,
Washington D.C. 20590; or go to http://www.safercar.gov. You can also obtain other information about
motor vehicle safety from the Hotline.
Upon request we will furnish any additional or more detailed maintenance and operational instructions
including any non-standard make of equipment that was specified and installed.
The following numbers are in Lufkin, Texas at the main office and manufacturing plant. Please contact
your factory branch or dealer first:
WARRANTY: [phone]
PARTS: [phone]
ENGINEERING: [phone]
A DIVISION OF LUFKIN INDUSTRIES, INC.
P.O. BOX 849, LUFKIN, TX 75902-0849 [phone]
GENERAL LOCATION, 7 MILES SOUTH OF LUFKIN ON U.S. HWY. 69
FACTORY BRANCHES—SALES
HOUSTON, TX 2929 Navigation Blvd. 77003 Phone: [phone]
SAN ANTONIO, TX 3343 Roosevelt 78214 Phone: [phone]
SHREVEPORT, LA 5409 E. Texas (Bossier City) 71111 Phone: [phone]

Page 4
OWNERS MANUAL FOR DUMP TRAILERS
INTRODUCTION PAGE 2
REPORTING SAFETY DEFECTS PAGE 3
SECTION 1 PAGE 8
1.1 SUSPENSIONS
1.1.1 TORQUE VALUES
1.1.1.1 SINGLE POINTS
1.1.1.2 AIR SPRING
1.1.1.3 MECHANICAL SPRING
1.1.2 AIR SPRING SUSPENSION INFORMATION
1.1.2.1 LIFT AXLE OPERATION
1.1.2.2 DUMP VALVE OPERATION
1.1.2.3 GENERAL ADJUSTMENT PROCEDURE FOR SETTING RIDE HEIGHT
1.1.3 ALIGNMENT
1.1.3.1 SPRING HUTCH
1.1.3.2 SINGLE-POINT SUSPENSION & AIR SPRING SUSPENSION
1.1.3.3 ALIGNMENT PROCEDURE
1.1.4 ADDITIONAL SUSPENSION MAINTENANCE CHECKS
SECTION 2 PAGE 16
2.1 AXLE MAINTENANCE
2.1.1 WHEEL BEARING/SPINDLE NUT ADJUSTMENT
2.1.2 WHEEL BEARING CAUTIONS
2.1.3 OIL SEALS
SECTION 3 PAGE 18
3.1 AUTOMATIC SLACK ADJUSTERS (ASA)

Page 5
3.2 AIR SYSTEM MAINTENANCE
3.2.1 BRAKE AIR ACTUATION MAINTENANCE
3.3 ANTILOCK BRAKE SYSTEM—(ABS)
SECTION 4 PAGE 21
4.1 ELECTRICAL/LIGHTING SYSTEM
SECTION 5 PAGE 22
5.1 TIRES
5.1.1 GENERAL INFORMATION
5.1.2 SAFETY RECOMMENDATIONS FOR TRAILER TIRES
SECTION 6 PAGE 24
6.1 WHEELS AND RIMS
6.1.1 HUB-PILOTED MOUNTING
6.1.2 STUD-PILOTED MOUNTING
6.1.3 RIM AND WHEEL MAINTENANCE
SECTION 7 PAGE 29
7.1 LANDING GEAR—GENERAL
7.1.1 MAINTENANCE
7.1.2 EMPTY WEIGHT
SECTION 8 PAGE 30
8.1 KING PIN AND UPPER COUPLER
8.2 INSPECTION CRITERIA
8.3 FIFTH WHEELS
8.3.1 FIFTH WHEEL MAINTENANCE

Page 6
SECTION 9 PAGE 31
9.1 END DUMP TRAILER OPERATING INSTRUCTIONS
9.2 LOADING PROCEDURES AND METHODS
9.2.1 HOPPER
9.2.2 END LOADER
9.2.3 CROWN LOADING
9.3 TARPING
9.4 COMMODITIES
9.5 UNLOADING
9.5.1 STOCK PILE
9.5.2 HOPPER
9.5.3 WINDROW
9.5.4 SPREAD OPERATION
9.6 TAIL GATE OPERATION
9.6.1 OPEN TAILGATE
9.6.2 LOCK TAILGATE
9.6.3 TAILGATE SAFETY REMINDERS
9.7 HOIST OPERATION
9.7.1 POWER TAKE-OFF CONTROLS
9.7.2 HOIST CONTROL
9.7.3 OPERATION OF HOIST
9.7.4 IN TRANSIT
9.7.5 HYDRAULIC HOSES
9.8 TIP-OVER CONDITIONS
9.8.1 WIND
9.8.2 TERRAIN
9.8.3 HUNG LOADS
9.8.4 JACKKNIFE

Page 7
9.8.5 TIRES
9.8.6 HUMPING
9.8.6 STAY AT CONTROLS
9.8.7 OVERLOADING
9.8.8 SUSPENSION
9.9 MAXIMUM HEIGHT AND DUMP ANGLE
SECTION 10 PAGE 37
10.1 END DUMP MAINTENANCE
10.1.1 TAILGATE LATCHES AND ASSEMBLY
10.1.2 FIFTH WHEEL ASSEMBLY
10.1.3 HYDRAULIC CYLINDERS
10.1.4 FLOORS AND WALLS
10.2 BOTTOM DUMP MAINTENANCE
10.2.1 DOOR HINGE PIVOT PINS
10.2.2 FIFTH WHEEL ASSEMBLY
10.2.3 AIR LINE LUBRICATOR
10.2.4 DOORS AND WALLS
SECTION 11 PAGE 39
11.1 TRAILER DECALS
SECTION 12 PAGE 45
12.1 SUPPLIER SECTION
LAWS, REGULATIONS, AND INDUSTRY STANDARDS PAGE 48
LIMITED WARRANTY PAGE 49

Page 8
SECTION 1
1.1 SUSPENSIONS
1.1.1 TORQUE VALUES
The suspension is the assembly that connects the axles to the trailer frame and absorbs shock
loads and braking loads through the leaf springs or air springs (air bags). It is therefore important
that it be maintained.
The life of the suspension depends upon keeping the connections tight. These bolts can become
loose from vibration and shock and, if not properly maintained at recommended torque, will shorten
the life of the suspension, reduce tire life, and eventual failure of the suspension, which could cause
a serious accident.
The following suspensions are standard on LUFKIN Trailers and the torque given must be
maintained at the recommended intervals as well as the periodic inspections as listed.
All fasteners on the suspension of your new LUFKIN Trailer were torqued before delivery to the
proper torque values. Due to vibration and shock loads it is necessary after a break-in period of
1000 miles or three months, and every six (6) months thereafter, to tighten all nuts and bolts to the
recommended torque. Always check the torque on the nut and not on the head of the bolt. Do not
lubricate the threads unless values given are for lubricated threads.
1.1.1.1 SINGLE POINTS
HOLLAND NEWAY TS SERIES LINK TO VENDOR FILE

Page 9
HUTCH 900/440 SERIES
1.1.1.2 AIR SPRING
NEWAY RL SERIES
HENDRICKSON INTRAAX SERIES
LINK TO VENDOR FILE
LINK TO VENDOR FILE
LINK TO VENDOR FILE

Page 10
HENDRICKSON NHT SERIES
1.1.1.3 MECHANICAL SPRING
HUTCH 9700 SERIES
1.1.2 AIR SPRING SUSPENSION INFORMATION
Regular preventive maintenance checks on air spring suspensions are the same as on leaf spring
suspensions with the addition of the air bags and air components. With the air pressure above 65
psi, the height between axle and frame should be within 1/4” of the same height at all air bags. If
not, it may be an indication of air loss at one or more air bags, air leaks at fittings, or malfunctioning
leveling valves. Leveling valves should have proper clearance to permit leveling arm to actuate
freely and not be bent or twisted. Do not grease leveling valves. There is a time delay of 2 to 6
seconds before the leveling valve will add or exhaust air to the air springs. The proper position of
the valve actuating lever is in the center or neutral. Lever up will add air; lever down will exhaust air.
Check leveling valve lever for being in proper position while trailer is connected to tractor in drive
away condition.
In the event of failure in one or more air springs, it is recommended the height control valve linkage
LINK TO VENDOR FILE
LINK TO VENDOR FILE

Page 11
be disconnected and the lever arm be rotated to a vertical down position. This will exhaust air from
the bags, allowing load to be carried on internal rubber stops within the bags. This procedure is
intended for temporary operation only. See Figure 1.
Figure 1 - AIR SPRING LEVELING VALVE
Air spring suspensions are equipped with an air brake protection valve. Check and clean air filter
periodically. This valve and filter are located on the air reservoir that supplies the air for the air
suspension. Additional filters are located in the input and output ports of the height control valves.
Check periodically. For more information on height control valves click on the link below.
Hendrickson height control valves
1.1.2.1 LIFT AXLE OPERATION
Caution must be exercised when using lift axles. Frame damage can result, as well as
bending axles, should the liftable axle be raised under loaded conditions which will
transfer additional weight to the axles remaining on the ground.
1.1.2.2 DUMP VALVE OPERATION
If specified by the customer, a trailer may be equipped with a dump valve. An air ride end
dump is equipped with an automatic dump valve that is activated when the trailer starts
the dump cycle. This allows the air to be exhausted from the bags, increasing stability by
eliminating the possibility of air bag failure. When using a trailer equipped with a dump
valve you should do the following:
IT IS IMPERATIVE THAT ALL AIR BE EXHAUSTED FROM AN AIR
RIDE SUSPENSION BEFORE THE DUMP CYCLE IS INITIATED.
TIPOVER CAN RESULT DUE TO INSTABILITY!
LINK TO VENDOR FILE

Page 12
- Always check to be sure all air bags are fully inflated before driving away.
- Do not operate loaded trailer in excess of five miles per hour (5 mph) with
current applied and air bags exhausted.
- Do not operate trailer when air bags are exhausted except in parking lots or
loading areas.
- It is unlawful to operate trailers with air bags exhausted on public
thoroughfares.
1.1.2.3 GENERAL ADJUSTMENT PROCEDURES FOR SETTING RIDE HEIGHT
Figure 2
1.1.2.3.1 Level the trailer so that mounting surface of suspension is parallel to
centerline of axles.
1.1.2.3.2 Verify proper ride height of suspension by looking at tag on suspension or
calling LUFKIN Trailers.
1.1.2.3.3 Block axle to trailer frame to proper dimension by subtracting 1/2 of axle O.D.
from ride height. Cut a block of wood to this dimension, and insert the block
between axle and frame. Lower trailer onto this block.
1.1.2.3.4 Center the leveling valve to neutral position, adjust linkage, and secure it.
1.1.2.3.5 Remove blocks. Apply air and verify ride height.
1.1.3 ALIGNMENT
1.1.3.1 SPRING HUTCH
Your new LUFKIN Trailer was aligned at the factory before delivery. For safe and efficient
operation and to prevent excessive tire wear, off tracking and hard pulling it is
recommended that after a short break-in period you have a qualified trailer mechanic
check the alignment.
LINK TO VENDOR FILE

Page 13
To align a four (4) spring suspension there is one adjustable torque arm on each axle.
Release the clamps at each end of the adjusting screw. Align front axle with the king pin
and adjust each axle thereafter parallel to the front axle. Be sure to secure the clamps on
the adjustable torque arm after alignment. See Figure 3.
Figure 3
1.1.3.2 SINGLE POINT SUSPENSION & AIR SINGLE SUSPENSION
Single Point and some Air Spring suspensions are aligned during installation and welded
in place. If alignment is required, it is necessary to burn loose the inner and outer
adjusting bushing to realign.
Many Air Spring suspensions feature adjustable non-welded pivot bolts. Be sure to re-
torque these to recommended values after realignment.
Visual checks of these suspensions should be made periodically. Check the rubber
bushing on the end of the trunnion tube of single point suspensions. If frayed and torn
this could be an indication of loose “U” bolts.
1.1.3.3 ALIGNMENT PROCEDURE
1.1.3.3.1 Before taking axle alignment measurements, make sure the trailer is
unloaded and free the suspension of any “binds” by pushing the trailer
backwards and then pulling the trailer forward. While pulling the trailer
forward on a level floor, apply the brakes and release. This will assure that
an adjustable undercarriage is in its rearmost locked position. Trailers with air
ride suspensions shall be aligned with the suspension at its nominal ride
height. The trailer MUST be level from side to side as well as from front to
rear.
Note: Neither service nor parking brakes should be applied during the
measurement procedure.
1.1.3.3.2 Use axle end extenders (or remove outer wheels and any obstructions) to
achieve a straight line for measuring from king pin to the axle ends.
1.1.3.3.3 Proper tools for axle alignment inspection are:
A. Spring loaded, kingpin extender with bubble level.
B. Axle end extenders.
C. 50 ft. steel tape.
D. Adjustable tram.
E. Gauge for measuring axle center to axle center.
Torque Arm Clamp Bolts

Page 14
1.1.3.3.4 Measure distances A and B from the king pin to the front axle. Refer to
Figure 4. These must be equal within 1/8 inch of each other. Measure
distances C and D between axles using gauge as shown in Figure 5. Note
that all currently available trailer axles have dimples or recesses at the center
of the axle spindle ends. These also must be equal within 1/16 inch of each
other. Determine lateral centerline of trailer body and axles. Distance E
should not exceed 1/4 inch for either axle. (Distance E is the distance
between axle and trailer centerlines.)
Figure 4
Figure 5
Gauge for measuring axle centers
* The gauge can be made of drill rod and must be rigid and true. The pointer arms of the
gauge must be parallel and held at the same height.
1.1.3.3.5 Precautions:
A. Always measure to the front axle ends for accurate alignment.
B. Avoid measuring to rims, suspension brackets, hub cap vent holes,
brake drums and the like. This can result in improper alignment.
C. If difficulty is encountered in obtaining true alignment, check and repair
or replace problem suspension parts.
D. Always align any succeeding axles with the front axles, not the kingpin.
A
DJUSTABLE

Page 15
1.1.4 ADDITIONAL SUSPENSION MAINTENANCE CHECKS
Check leaf springs for broken leaves. Replace broken leaves immediately to prevent the other
leaves from being overloaded. On taper leaf springs be sure the plastic liner is serviceable and on
top of the spring. The liners between leaves should be in place and serviceable. Replace with
factory approved liners if necessary.
Torque arms should be checked for being tight. If slack is found it should be repaired immediately
since this indicates that there is wear in the rubber bushing or torque arm parts. Check the
adjustable torque arm clamps for being tight. Loose clamps will cause wear on the adjusting threads
and the suspension cannot be kept in alignment.
On leaf spring type suspensions, have the trailer checked for axle alignment after two to three
thousand miles.
FAILURE TO TAKE THE PREVENTIVE MAINTENANCE PRO-
CEDURES ABOVE CAN RESULT IN ACCELERATED WEAR AND
LEAD TO MALFUNCTION AND POSSIBLE VEHICLE CRASH!

Page 16
SECTION 2
2.1 AXLE MAINTENANCE
The axle and its attached parts—bearings, hubs oil seals, brakes, cam shaft and slack adjusters—are all
assembled and are engaged in mechanical motion and require frequent maintenance. Preventative
maintenance on the axle can save on repair bills and prolong trailer life.
For information from axle manufacturers, see the links below:
ArvinMeritor Axles
Dana Axles
2.1.1 WHEEL BEARING/SPINDLE NUT ADJUSTMENT
To correctly check and adjust wheel bearings, the axle must be supported so wheels are clear of the
front and free to roll.
As standard equipment, LUFKIN employs the use of a one-piece spindle nut. Procedures for
installation and wheel bearing adjustment may be found by clicking on the links below.
Axilok Spindle Nut Installation
Stemco Spindle Nut Installation
Stemco Wheel Bearing Removal and Installation
2.1.2 WHEEL BEARING CAUTIONS
2.1.3.1 INSPECTIONS
2.1.3.1.1 Inspect condition of sight glass on hubcap; it should be clear and not
discolored. Change in color could indicate excessive heat. If cap is hot to the
touch, lube level in sight glass at proper level if oil is used.
2.1.3.1.2 For grease with solid metal cap, remove access cap and inspect for
presence of grease.
IMPROPER BEARING MAINTENANCE AND ADJUSTMENT CAN
RESULT IN OVERHEATING, WHEEL LOCK-UP, AND LOSS OF
ENTIRE WHEEL ASSEMBLY CAUSING A CRASH AND POSSIBLE
LOSS OF LIFE.
LINK TO VENDOR FILE
LINK TO VENDOR FILE
LINK TO VENDOR FILE
LINK TO VENDOR FILE
LINK TO VENDOR FILE

Page 17
2.1.3.1.3 Look for leaks on inside of wheels or hub, or as swirls on tire.
2.1.3.1.4 Check for abnormal tire wear.
2.1.3.2 During operation, bearing failure can result in:
- Wheel vibration
- Wheel wobble
- Wheel noise
- Smoke from wheel end
- Wheel lock-up and skidding
2.1.3 OIL SEALS
Check 0il level on plastic hubcap window. Do not overfill. Check oil level before each trip and
inspect for oil leaks. It is recommended that any time the hub is removed, that the complete oil seal
be replaced. Use gear type oil, SAE 80WE-90. Change oil, inspect bearings, and clean all parts in
hub at 50,000-mile intervals.
NOTE: When replacing oil with grease, consult seal manufacturer for proper seal and
hubcap that is compatible with the selected grease.
Procedures for seal installation may be found by clicking on the links below.
National Oil Seal Installation
Stemco Guardian Oil Seal Installation
Stemco Grit Guard Oil Seal Installation
LINK TO VENDOR FILE
LINK TO VENDOR FILE
LINK TO VENDOR FILE

Page 18
SECTION 3
3.1 AUTOMATIC SLACK ADJUSTERS (ASA)
The brakes were properly adjusted on your LUFKIN Trailer before delivery.
Automatic slack adjusters are required by law, effective on all trailers produced since December 1993.
Depending on the brand of slack adjuster used, the operating, and adjusting procedures may vary.
Procedures for adjusting slack adjusters may be found by clicking on the links below.
ArvinMeritor Automatic Slack Adjusters
Bendix Automatic Slack Adjusters
Gunite Automatic Slack Adjusters
Haldex Automatic Slack Adjusters
3.2 AIR SYSTEM MAINTENANCE
3.2.1 BRAKE AIR ACTUATION MAINTENANCE
The air system on your trailer is the system that actuates and releases the brakes on the trailer. It
also has a second separate function that controls the parking brake and emergency brake system.
It is important to maintain the system in good working order through preventive maintenance. This
system was checked with the latest test equipment at the factory for function and timing as
required by the Department of Transportation.
As the complexity of the air brake system has increased, so has the need for clean air. Many of the
later design valves contain small orifices and passages and thus, are more susceptible to
contaminants. The prevention of freeze-ups in the system is also equally important. The use of an
air dryer, filter, and alcohol evaporator is highly recommended.
The following items should be checked by properly trained personnel on a periodic basis and any
time brake problems occur.
3.2.1.1 The air system must be kept free of leaks. Check all connections while system is charged
with a minimum of 100 psi air pressure. Check seals on glad hands each time they are
coupled. Replace if leak occurs.
3.2.1.2 Anti-compounding two-way check valve on top of the spring brake valve can be checked
by charging the service line and emergency line, then disconnect each line—one at a
time—with the other charged. There should not be any bleed back from the open line. If
so, the anti-compounding valve is stuck or malfunctioning. There should not be any
continuous exhausting of air from the body vents or exhaust valve on the spring brake
valve.
LINK TO VENDOR FILE
LINK TO VENDOR FILE
LINK TO VENDOR FILE
LINK TO VENDOR FILE

Page 19
3.2.1.3 The relay valve should not have a continuous flow of air from the exhaust port except
immediately after a brake release. If air continues to discharge, it could be a malfunction
of the exhaust valve, or the “O” ring seal on the push rod of the spring brake chamber is
bad and is allowing air to be discharged through the service chamber and out the relay
valve exhaust port. To check this, the system must be charged, parking brakes off,
service brakes off, then disconnect the service hose at service brake chamber. If air is
discharging from service port, the “O” ring is bad. If air is escaping from service brake
hose, the exhaust valve is malfunctioning. Repair “O” ring seal or exhaust valve or
replace complete part.
Caging tools are supplied with trailer and are on a bracket attached to the trailer frame
near the spring brake chamber, or on the chamber. For vendor files on brake chambers,
see below.
DI-PRO Brake Chambers
MGM Brake Chambers
Air reservoir tanks should be drained daily to remove moisture and other contaminants.
More than once a day may be necessary in the winter when the humidity is high.
Parking brake application will begin after air pressure falls below 55 psi and application
increases as air pressure drops.
Parking brakes will start releasing after the system pressure reaches 55 psi and should
be fully released when pressure reaches 70 psi.
Parking brakes may be disengaged in an emergency by manually caging the spring in
each spring brake chamber using the tool provided. Do not operate the vehicle except in
emergency as there are no emergency brakes available when the spring brakes are
caged.
DO NOT REMOVE CLAMP RING FROM SPRING BRAKE CHAMBE
R
UNLESS SPRING IS PROPERLY CAGED! IF NOT CAGED, THE
INTERNAL SPRING WILL BE RELEASED WITH EXPLOSIVE
F
O
R
C
E AND MAY
C
A
US
E
S
EVERE B
O
DILY IN
JU
RY!
DO NOT OPERATE TRAILER WITH SPRING BRAKES CAGED, O
R
IN ANY WAY DISABLED, EXCEPT IN AN EMERGENCY SITUATION!
WHEN SPRING BRAKES ARE CAGED, THERE ARE NO
EMER
G
EN
C
Y BRAKE
S
AVAILABLE.
DO NOT ATTEMPT TO DISASSEMBLE
SPRING-BRAKE. THIS CAN RESULT IN FATAL INJURY.
LINK TO VENDOR FILE
LINK TO VENDOR FILE

Page 20
The following precautions should be observed when working on or around air brake
systems and components.
1. Stop vehicle engine and block vehicle wheels. Depleting vehicle air system pressure
may cause the vehicle to roll. Keep clear of chamber push rods and slack adjusters; they
may automatically apply as system air pressure drops.
2. Deplete all air pressure from the system before disconnecting a hose, plug, or
component.
3. Do not look into air jets or direct them at anyone. Always wear safety glasses when
working with air pressure as contaminants may be expelled and cause bodily harm.
4. Always read and understand recommended procedures before disassembling any
component. Warning and caution notices should be followed as some components
contain powerful springs and injury can result if not properly disassembled.
THE BRAKE SYSTEM ON LUFKIN TRAILERS IS DESIGNED AND CONSTRUCTED TO MEET FMVSS 121
REQUIREMENTS. IN ADDITION, COMPONENTS ARE SELECTED THAT WILL PROMOTE BRAKE BALANCE
BETWEEN TRACTOR AND TRAILER. IF ANY BRAKE COMPONENT IS REPLACED, IT SHOULD BE
REPLACED WITH AN EXACT DUPLICATE PART. THIS INCLUDES, BUT IS NOT LIMITED TO, RELAY
VALVES, QUICK RELEASE VALVES, BRAKE LINING, SLACK ADJUSTERS (SAME LENGTH), AND BRAKE
CHAMBER SIZE.
3.3 ANTILOCK BRAKE SYSTEM (ABS)
It is required by law that all trailers manufactured after March 1, 1998, have ABS. Your trailer may be
equipped with any brand currently available. Please see vendor links below for reference to installation and
trouble-shooting, or contact your LUFKIN representative.
Meritor-Wabco ABS
Bendix ABS
Because the law requires a constant power circuit for ABS, your trailer may be equipped with two
connectors on the front of the trailer. This arrangement provides electrical circuits for auxiliary equipment
that would normally use the middle pin on the J560 connector (Blue Wire) which now is dedicated to ABS.
The second connector is an ISO 3731, which is polarized to prevent inadvertent connection with the J560
plug. The ISO 3731 series is an auxiliary plug for the operation of auxiliary equipment.
LINK TO VENDOR FILE
LINK TO VENDOR FILE