TrailMax T-12-T User manual

®
page 1
T-12-T
Table of Contents
Section 1. Operation .................................................................................... 3
1.0 Introduction ................................................................................... 3
1.1 Purpose ........................................................................................ 3
1.2 Rating............................................................................................ 3
1.3 Design and Safety Factors ........................................................... 4
1.4 Vehicle Load and Handling Limits ................................................ 4
1.5 Reporting Safety Defects ............................................................. 7
1.6 Alert Symbols ................................................................................ 8
1.7 Pre-Trip Inspection........................................................................ 9
1.8 Hook-Up Procedures .................................................................. 10
1.9 Loading and Unloading .............................................................. 11
Trailers With Ramps ................................................................. 12
Trailers With Tilt Decks ............................................................. 12
Section 2. Maintenance .............................................................................. 13
2.0 Periodic Maintenance ................................................................. 13
2.1 Structural Components ............................................................... 14
Sub-Frame ................................................................................ 14
Deck .......................................................................................... 14
2.2 Sub-Assembly Components ....................................................... 14
Coupling ................................................................................... 14
Jack .......................................................................................... 15
Cushion Cylinder ...................................................................... 15
Deck Latch ................................................................................ 15
Deck Hinge Assembly ............................................................... 15
2.3 Running Gear ............................................................................. 16
Suspension ............................................................................... 16
Hubs and Drums ....................................................................... 16
Brake Drum Inspection ............................................................. 17
Bearing Inspection .................................................................... 17
Standard Bearing Lubrication ................................................... 18
E-Z Lube Bearing Lubrication .................................................. 18
Seal Inspection and Replacement ........................................... 19
Hub Reinstallation and Bearing Adjustment ............................ 19
2.4 Wheels and Tires ........................................................................ 20
Wheels ..................................................................................... 20
Tires .......................................................................................... 22
Inflation Pressure ..................................................................... 22
Tire Wear Diagnostic Chart ...................................................... 23
2.5 Electrical ..................................................................................... 24
Harnesses and Lights............................................................... 24
Junction Block .......................................................................... 24
Electrical Plug ........................................................................... 24
Contents
Rev A 6/1/06

®
page 2
T-12-T
2.6 Brake System (Common to Hydraulic and Electric) ................... 25
Brake Adjustment ..................................................................... 25
Brake Cleaning and Inspection ................................................ 26
Brake Lubrication ..................................................................... 26
2.7 Hydraulic Brake System ............................................................. 27
Operation .................................................................................. 27
Surge Actuator Maintenance .................................................... 27
Corrosive Environment Warning .............................................. 28
Hydraulic Lines ......................................................................... 28
Hydraulic Brakes ...................................................................... 28
Brake System Bleeding ............................................................ 29
Hydraulic Brake System Troubleshooting Chart ...................... 31
2.8 Electric Brake System................................................................. 31
Operation .................................................................................. 31
Using your Brakes Properly...................................................... 32
Synchronization ........................................................................ 33
Controllers ................................................................................ 33
Magnets .................................................................................... 34
Electric Brake System Troubleshooting ................................... 35
Measuring Voltage .................................................................... 35
Measuring Amperage ............................................................... 37
Electric Brake System Troubleshooting Chart ......................... 38
2.9 Pre-Storage Maintenance ........................................................... 40
2.10 Pre-Season Maintenance ........................................................... 41
Section 3. Parts .......................................................................................... 38
3.1 Structural Components ............................................................... 38
Sub Frame ................................................................................ 38
Deck Surface ............................................................................ 39
3.2 Major Sub-Assemblies ................................................................ 40
Hammerblow Drop Leg Jack .................................................... 40
Couplers ................................................................................... 41
Deck Latch Assembly ............................................................... 43
Cushion Cylinder....................................................................... 44
3.3 Running Gear .............................................................................. 45
Suspension, 7K......................................................................... 45
Electric Brake Components, 7K ............................................... 46
Axle End Components .............................................................. 48
3.4 Wheels and Tires ........................................................................ 49
3.5 Electrical ..................................................................................... 50
Harnesses and Lights ............................................................... 50
Electrical Plug ........................................................................... 52
Electric Brake Wiring ................................................................ 53
Electric Breakaway System ...................................................... 53
Section 4. Warranty Claim Procedure ....................................................... 54
Contents

®
page 3
T-12-T
Section 1. Operation
1.0 Introduction
This section describes how trailers can have different operational characteristics
based on design, load configuration, gross weights, suspension characteristics, articu-
lation and extreme differences between loaded and unloaded weights.
Trailers have safe operating limits just as automobiles, airplanes, and other ve-
hicles. The interaction of the vehicle characteristics, maintenance, load, roadway,
weather, the skill of the driver and vehicle speed affect these limits. Knowledge of how
these factors affect the vehicle’s operating limits and utilization of defensive driving
techniques should result in safer driving.
1.1 Purpose
The purpose of this section is to describe how the vehicle characteristics, mainte-
nance, road conditions, and weather can affect trailer control and stability limits, and
how driver awareness and skill can help compensate for these factors. This knowledge
will assist you to safely enjoy the maximum utility and productivity from your trailer.
First and foremost, DO NOT operate the trailer until you have read and fully under-
stand this instruction and operating manual. It is also important that each and every
person who operates the trailer be given the opportunity to read this manual.
1.2 Rating
Gross Axle Weight Rating (GAWR) is the rated load-carrying capacity of an indi-
vidual axle and wheel assembly. It represents the load that may be steadily sustained
by the components in the system; i.e., tires, wheels, hubs, bearings, axles, brakes,
suspension, sub-frame, etc. with the GAWR limited by the component with the lowest
working rating. Consideration of environmental and operational factors may require the
manufacturer to reduce the nominal rating.
Gross Vehicle Weight Rating (GVWR) is the maximum rated combined weight of a
trailer and its payload (uniformly distributed) based on its structural capabilities.
Operation
O
P
E
R
A
T
I
O
N

®
page 4
T-12-T
1.3 Design and Safety Factors
The safety factor is a ratio between the design stress imposed by the load sitting
static on the trailer and the minimum yield stress of the steel used in construction of
that trailer structure. For example, if the structure is built using 50,000 psi minimum
yield strength steel and the load sitting on it causes a stress level of 25,000 psi then a
2:1 safety factor would exist. THIS SAFETY FACTOR DOES NOT MEAN THAT THE
STRUCTURE CAN THEN BE USED TO CARRY TWICE THE RATED LOAD. Under
dynamic conditions, or as the trailer moves and encounters shocks, vibrations, twists
and other conditions that exist during transport, stress levels are elevated far beyond
those in the static situation.
Distributed Load is when a load is distributed evenly over the length of the trailer
deck. This would be considered as the ideal load scenario when fully loaded to rated
capacity.
Concentrated Load is one that is localized over a shorter than normal distance and
imposes greater stress in the concentrated load areas. Under these conditions, it is not
recommended to carry the full rated capacity of the trailer. Extreme concentrated appli-
cations may require additional support for the load.
1.4 Vehicle Load and Handling Limits
Vehicle handling limits can be greatly affected by the weight of a load, its place-
ment, the amount of weight distributed over the axles and whether or not the load is
secured properly.
Tow vehicle and trailer combinations are designed to provide maximum directional
control and roll stability within the constraints of highway size and weight limits. Any
combination can be rolled over by driving too fast around a curve, making too abrupt a
maneuver, or by leaving the roadway. Locking up the wheels on an axle can result in a
jackknife or trailer swing out.
One of the major contributing factors to vehicle rollover is high center of gravity on
tall loads. Extreme caution should be used in maneuvering a vehicle and trailer combi-
nation, or any unit that has a tall load. Positioning the load in a central side to side
location will enhance directional control, roll stability and braking.
You should be aware that trailers with a shorter wheel base are more prone to roll
during an abrupt lane change or quick reactions at the wheel. This tendency can be
made dramatically worse with a tall, high center of gravity load.
Operation

®
page 5
T-12-T
Overloading a vehicle should never be permitted. Overloading results in tire blow-
outs, spring breakage, frame damage, diminished braking capacity, and will severely
alter the vehicle’s normal handling characteristics. All vehicles are designed with a
maximum load capability. To best utilize these vehicles in the safest manner the loads
as shown on the certificate label should not be exceeded.
Adequate tongue weight is required for trailers to tow correctly. Inadequate tongue
weight can cause a “whipping action” particularly in shorter wheel base trailers. Too
much tongue weight can overload tow vehicle hitch resulting in reduced steering load
and loss of steering control. Selecting the correct tow vehicle is crucial for the applica-
tion.
Always maintain enough braking and stopping distance. Erratic or unequal brake
action from side to side on either tow vehicle or trailer can cause handling problems in
braking situations. A balance between tow vehicle and trailer on brake application and
release timing and synchronized pressure will reduce push/pull characteristics which
when excessive, may result in jackknife. The use of properly matched brake lining is
recommended to enhance safer braking.
Proper alignment of both tow vehicle and trailer wheels will add significantly to the
handling characteristics of the combination and allow the driver to utilize all the design
responses of the vehicle to make evasive maneuvers in the safest manner.
Irregular terrain, steep grades and crowned roads, especially rural roadways, free-
ways, exit ramps, curves, bumps and depressions introduce forces into a tow vehicle/
trailer combination that could result in an accident if proper precautions and driving
techniques are not followed. Even a vehicle that meets all maintenance and load re-
quirements can become hazardous when excessive speeds and certain roadway char-
acteristics are combined.
While on a downgrade, the force of gravity works against the driver in maintaining
control of the vehicle, particularly if the road surface is wet or slick from snow and ice
or loose material. On upgrades, the problem is spinning out due to insufficient traction
at the drive wheels, particularly on snow and ice.
Great care must be taken to avoid excessive use of brakes on long downgrades.
Overheated brakes are dangerously inefficient. It is very dangerous to brake on a
downgrade using only the trailer brakes. If this is done, the trailer brakes heat up and
fade and the tow vehicle brakes alone will not be able to stop the combination by
themselves. Drivers should reduce speed, downshift and use engine compression as
the principal means of controlling speed on long grades and using all brakes so brake
temperatures can be held to a safe level.
Operation
O
P
E
R
A
T
I
O
N

®
page 6
T-12-T
Operation
Weather conditions can be a major factor in the cause of accidents. Rain, ice, snow,
high winds and visibility combined with excessive speed, sudden lane changes, or
other factors that put lateral forces into a tow vehicle trailer combination contribute
significantly to an accident.
Slippery roads can increase stopping distances and reduce the ability to control the
vehicle. When the road is wet, the available tire/road friction may be half that of a dry
road, and icy roads can reduce friction many times over wet roads. If hard braking or
rapid acceleration occurs, there may be little or no friction available to prevent tire
lateral movement and skidding results.
The driver has a responsibility to compensate for the characteristics and conditions
of his vehicle, the road conditions and weather. Reducing speeds and increasing atten-
tiveness may compensate for most of these conditions. The more familiar the driver is
with the vehicle and the road, the less likely he will need to make abrupt emergency
maneuvers which will take the vehicle to its limits. Control and stability may be main-
tained if the driver knows his vehicle, his load, and the road.
Either braking or accelerating while cornering can significantly reduce the control-
lability and stability of the vehicle and should be avoided. The best driving practice is to
decelerate to a safe conservative speed before entering a corner or approaching con-
gested traffic and then apply only moderate power until an essentially straight path has
been established.
It is imperative that a safe speed always be maintained. The safe speed is that
speed at which control can be maintained over the vehicle at all times. This speed will
allow an emergency change of lane maneuver, travel off an exit ramp with a tightening
radius and recovery from pavement drop-off or wet pavement. This speed will vary from
one combination of vehicle to another and takes into consideration such factors as
road conditions, weather, traffic, visibility, type of load and experience of the driver.

®
page 7
T-12-T
1.5 Reporting Safety Defects
If you believe that your vehicle has a defect that could cause a crash, injury, or death,
you should immediately inform the National Highway Traffic Safety Administration (NHTSA)
in addition to notifying Gem State Mfg., Inc.
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 pursue a remedy campaign and recall
those vehicles. However, NHTSA cannot become involved in individual problems between
you, your dealer, or Gem State Mfg., Inc.
To contact NHTSA, you may either call the Vehicle Safety Hotline toll free at 1-888-327-
4236 (TTY: 1-800-424-9153), go to http://www.safecar.gov; or write to Administrator,
NHTSA, 400 Seventh Street SW., Washington, DC 20590. You can also obtain other
information about motor vehicle safety from http://www.safecar.gov.
Operation
O
P
E
R
A
T
I
O
N

®
page 8
T-12-T
Operation
1.6 Alert Symbols
It is important that your know the meaning of the following symbols that are used
throughout this document.
SAFETY ALERT!
This is the safety alert symbol. It is used to alert you to potential per-
sonal injury hazards. Obey all safety messages that follow this symbol to
avoid possible injury or death.
DANGER!
DANGER! indicates an imminently hazardous situation which, if not
avoided, will result in death or serious injury.
WARNING!
WARNING indicates a potentially hazardous situation which, if not
avoided, could result in death or serious injury.
CAUTION!
CAUTION indicates a potentially hazardous situation which, if not
avoided, may result in minor or moderate injury.
CAUTION
CAUTION used without the safety alert symbol indicates a potentially
hazardous situation which, if not avoided, may result in property damage.
!
DANGER
!
WARNING
!
CAUTION
!
CAUTION

®
page 9
T-12-T
1.7 Pre-Trip Inspection
There are some items on every vehicle combination that can be and should be
inspected prior to every trip that require no special knowledge, training, or sophisti-
cated equipment.
Before beginning a trip, make a thorough visual inspection of the trailer for cracks
in the structure, or bent components such as the tongue or frame. Check for any miss-
ing fasteners in suspension as well as other areas, and look for broken or bent springs
and spring hangers or otherwise damaged components.
Verify that the hitch on the tow vehicle is the correct size and configuration to fit the
trailer coupling. The hitch must be rated to meet or exceed the Gross Vehicle Weight
Rating (GVWR) of the trailer.
Check the hitch height of the trailer and compare it to the tow vehicle; it is very
important that the trailer be towed in the level position when loaded. In order to achieve
the correct hitch height, elevate the tongue of the trailer slightly (1" to 2") by adjusting
the trailer hitch to compensate for settling of tow vehicle springs when loaded.
Always visually inspect hitch for unusual appearances such as bent components,
cracks in welds or chipped paint where stress cracks may appear from high loads.
Check tires for proper inflation. Tire manufacturers recommend checking inflation
pressure while trailer is not loaded and tires are cool. This will provide a more accurate
reading. A drop of 10 PSI in tire pressure can reduce the carrying capacity of the tire as
much as 20%. This reduced capacity could cause tire failure and poor tire life.
Maintaining proper wheel nut torque value is essential to prevent wheel end sepa-
ration or potential damage to the hub or wheel. Always check wheel nuts every 50 to
100 miles for the first 200 miles of operation, then periodically thereafter. The same
procedure should be repeated after dismount and remount of wheels. It is important to
follow the specified tightening sequence recommended in the tire maintenance section
of this manual.
NOTE: For trailers with hydraulic surge brakes, check the brake fluid reservoir
level and add brake fluid to the fill line if necessary.
Operation
O
P
E
R
A
T
I
O
N

®
page 10
T-12-T
1.8 Hook-Up Procedures
Connect the tow vehicle to the trailer and check that the coupler is completely latched.
Be sure that a safety pin is inserted to ensure coupler will not unlatch during transport.
Connect the electrical plug from the trailer’s harness to the receptacle of the tow
vehicle. Check all lights on the trailer to make sure they are working correctly with the
tow vehicle’s electrical system.
Be sure the landing leg and drop foot are fully retracted and the crank handle is
stowed in transport position. For trailers with 2-speed jacks, use low gear for raising
and lower the jack under load, and high gear for raising and lowering the leg when it is
off the ground.
Check all safety chains and their attachment to both the trailer and the towing ve-
hicle. Connect safety chains to tow vehicle using crossed pattern under tongue. Allow
slack for turning, but avoid having chains drag on pavement. Make certain that all
attachment devices are properly installed and in good working order.
For trailers with air brakes, connect the Glad Hands (one service and one emer-
gency) to tow vehicle. Shut off petcock(s) on air tank(s) or if already shut, open to
exhaust all moisture, then shut off. It is very important that the air system be drained of
moisture after each use to keep all components functioning properly and to make equip-
ment safe.
Trailers with electric brakes or hydraulic surge brakes come equipped with an emer-
gency breakaway device. The breakaway system is designed to operate after the cou-
pling system has failed. Connect breakaway chain S-hook to bumper or hitch on tow
vehicle. Allow slack for turning, but avoid letting chain drag on pavement. Provide as
straight a connection as possible.
The breakaway system is for emergencies and is not a parking brake.
The following paragraphs pertain to trailers with hydraulic surge brakes:
The ‘surge’ or ‘push’ of the trailer toward the tow vehicle when the tow vehicle
brakes are applied actuates the trailer brakes. Excessive surge actuator travel (over
one inch) when brakes are applied indicates a need to adjust the trailer brakes.
Should the breakaway be accidentally applied while unhitching, pry the breakaway
locks apart to release lever.
Sway control devices that restrict operation of the actuator cannot be used. The
actuator must be free to telescope in response to braking requirements.
Operation

®
page 11
T-12-T
Operation
1.9 Loading and Unloading
TRAILER LOADING PRACTICES
The consequences of ignoring proper trailer loading practices can be
very serious. Failure to adhere to the information in this section could
lead to unsafe handling, diminished braking capacity, or other unstable
trailer characteristics which could result in an accident causing property
damage, bodily injury or death.
It is the operators responsibility to take whatever steps necessary to load the
trailer properly, even when it is not easy to calculate the total load or determine
the load center of gravity.
A decal on the trailer similar to the one shown below indicates the correct place-
ment of the load. Load the trailer so that 60% of the total load weight is forward of the
arrow, and 40% is rearward of the arrow. This will ensure that the proper load balance
and tongue weight are achieved.
O
P
E
R
A
T
I
O
N
WARNING
!
MAINTAIN 60% OF LOAD
FORWARD OF THIS POINT
(REFER TO OWNERS MANUAL)
ADVERSE WEATHER CONDITIONS!
Adverse weather conditions can cause wet and slippery trailer decks
and ramps. Depending on the type of equipment and typical weather
conditions it may be necessary to add traction aids to the trailer deck and
ramps.
CAUTION
!
CAUTION
!

®
page 12
T-12-T
Always use extreme caution when loading and unloading equipment on trailer. Make
sure road surface is level. Loading and unloading on an uneven surface may cause
damage to the trailer frame and create unsafe loading conditions.
Always set brakes on tow vehicle and trailer before loading and unloading and use
chock blocks as an added safety precaution.
Before securing equipment, always lower booms, loaders and buckets. The parking
brake on the equipment being transported must be engaged, where applicable. Always
make sure you are under the maximum allowable height clearance.
Equipment with crawler tracks as well as wheel type equipment should be restrained
in the lateral, forward, rearward and vertical direction using a minimum of four direct
tie-downs and binders each having a working load limit of at least 5000 lbs. and should
be blocked to prevent forward movement.
Articulated vehicles shall be restrained in a manner that prevents articulation while
in transit.
Trailers With Ramps
Loading ramps can be adjusted for various track widths. Prior to loading or unload-
ing it is very important that ramps are adjusted to proper spacing for equipment being
transported. When loading equipment onto deck, drive slowly forward until appropriate
tongue load is achieved. Ramps are designed to support rear of trailer during loading
and unloading. Ramps must be in stored position during transport.
Trailers With Tilt Decks
It is very important that the deck latch is in the locked position with the safety pin
inserted at all times during transport. Always unlock deck when unloading equipment.
Failure to do this may result in damage to deck. Deck latch is adjustable to keep deck
tight and rattle free.
When loading equipment onto deck, drive slowly until deck begins to tilt closed, and
proceed forward until 10% of load weight in on the hitch of trailer. Not enough tongue
weight can result in swaying of trailer, which can be an unsafe condition.
When unloading use reverse procedure as loading. Back up slowly until deck be-
gins to tilt, stop and wait for deck to completely open, then proceed to back off slowly.
Trailer deck will tilt open and tilt closed with one persons weight. The deck may tilt
faster or slower depending on outside temperature, because the temperature affects
the density of the fluid in the deck cylinder.
Operation

®
page 13
T-12-T
Section 2. Maintenance
2.0 Periodic Maintenance
Pre-Trip Inspection-
Check brake fluid level- see ‘Surge Actuator Maintenance’ on page 27.
Lube coupler- see ‘Coupling’ on page 14.
Examine frame and tongue members for evidence of damage or cracked welds.
Check lights for correct operation.
Weekly-Weekly-
Check cold tire pressures- see ‘Inflation Pressure’ on page 22.
Check lug nut torque- see page 21.
Monthly-
Check for loose or missing suspension fasteners.
Check brake adjustment- see page 25.
Quarterly-
Lube Dico surge actuator rollers- see ‘Surge Actuator Maintenance’ on page 27.
Annually-
Pack wheel bearings- see page 18.
Inspect brakes and linings- see page 26.
Bi-annually-
Flush brake fluid and bleed system- see page 29.
Grease deck hinge- see page 15.
Special-
Submerged axles- immediately re-pack wheel bearings. Check brake linings for
contamination.
Accident or Overload- check all structural components for damage. Check tires and
wheels for damage.
Skidding-check tires for flat spots.
Maintenance
M
A
I
N
T
E
N
A
N
C
E

®
page 14
T-12-T
Maintenance
2.1 Structural Components
Sub-Frame
Other than for periodic or special inspections the trailer sub-frame requires no regular
maintenance other than washing. Keeping the trailer clean will help you notice other
things such as cracked welds or leaking brake fluid. If your application requires the
hauling of corrosives then frequent washdowns are very important.
Deck
The deck is the major load-carrying member of the trailer. It requires no regular
maintenance other than a periodic check for broken welds, loose fasteners and corro-
sion. If the trailer has been overloaded or in an accident, inspect the deck carefully.
Your trailer has one of two types of decking material, either rubber compound or
wood. For wood decks it may be necessary to apply a new coat of wood preservative
after decking has aged and become dry. The best time to apply preservative is during
warm weather for better penetration.
The rubber compound material requires no particular maintenance.
Replace decking when necessary. Occasionally check for loose, missing, or broken
deck screws.
2.2 Sub-Assembly Components
Coupling
Your trailer has either a pintle eye or ball type coupling. Check for cracks, loose
fasteners and wear. Regularly apply a coating of grease to the hitch contact areas of
the coupling to prevent accelerated wear.
The fasteners for the coupling are very important and deserve careful
attention.Replace the bolts if they are damaged in any way, and replace the locknuts if
worn. Using a torque wrench, torque the fasteners to value shown on the decal near
the coupling on the trailer tongue.

®
page 15
T-12-T
Jack
As necessary, grease the jack lead screw using the following procedure:
1. Fully extend the jack and apply grease to the lead screw through the grease port
(hole) in the side of the jack body.
2. Cycle the jack up and down several times to distribute the grease on the screw.
The following three sub-sections pertain to trailers with tilt decks-
Cushion Cylinder
The fluid in the cylinder should be changed if the cylinder has leaked or if the deck
action has become jerky and/or sluggish. Fully collapse the cylinder, and then remove
the filler plug and drain out the old fluid. Add 10W hydraulic fluid until the cylinder is full
and all the air has been expelled.
Deck Latch
If the latch becomes difficult to operate apply some penetrating lubricant to the
moving parts. Should the deck develop a rattle, adjust the hook receiver assembly on
the tilt deck.
Deck Hinge Assembly
The hinge assembly is highly stressed during loading and unloading, and so check
it for cracked welds frequently.
Every six months, or sooner if service dictates, grease the deck hinges. Apply grease
to the fittings (one per side) until fresh grease becomes visible.
Maintenance
M
A
I
N
T
E
N
A
N
C
E

®
page 16
T-12-T
2.3 Running Gear
Suspension
The suspension on your trailer is either a rubber torsion axle type or the slipper leaf
spring type. Rubber torsion suspensions require no maintenance.
Slipper springs have an eye formed in one end of the spring only with the other end
formed into a reverse curve. The attachment of these springs is as follows:
1. The front eye is attached directly into the front hanger with a bolt and nut.
2. The rear end of the spring is captured in the rear hanger or equalizer with a
‘keeper bolt’ that prevents the spring from coming out when the trailer is jacked up for
service.
Visually inspect the suspension system every 6,000 miles for signs of excess wear,
elongation of bolt holes, and loosening of fasteners. Whenever loose or replaced the
fasteners in your suspension system should be torqued as detailed below:
1. U-bolt- 45 to 60 lbs.-ft.
2. Shoulder Type shackle bolt- 30 to 50 lbs.-ft.
3. Fasteners with castle nuts- snug fit only. The cotter pin will retain the nut-bolt
assembly.
Hubs and Drums
Hub Removal- Whenever the hub equipment on your trailer must be removed for
inspection or maintenance the following procedure should be utilized:
1. Before jacking up the wheel, break loose the wheel lug nuts. Do not loosen them
more than 1/2turn while the trailer wheel is still on the ground.
2. Jack up the wheel. Use a jack stand to support the axle. If the wheel does not
rotate freely, back off the brake adjustment. Remove the wheel.
3. Remove the grease cap (hubcap) by carefully prying progressively around the
flange of the cap.
Maintenance

®
page 17
T-12-T
4. Remove the cotter pin from the spindle nut.
5. Unscrew the spindle nut and remove the spindle washer.
6. Remove the hub from the spindle, being careful not to allow the outer bearing
cone to fall out. The inner bearing cone should be retained by the grease seal.
Brake Drum Inspection
The critical surface of the brake drum is the contact area for the brake shoes during
stopping. Check for excessive wear or heavy scoring. If the drum is scored or out of
round, it should be machined. For a 12" brake drum, the inside diameter must be no
greater than 12.090" after machining.
Bearing Inspection
Wash all grease and oil from the bearing cone using a suitable solvent. Dry the
bearing with compressed air or a lint-free cloth and inspect each roller completely. Also
clean and inspect the cups (races) inside the hub. Any pitting, spalling, bluing (heat
damage) or corrosion is cause for replacement.
NOTE: Bearings must always be replaced in sets of a cone and cup.
RISK OF PERSONAL INJURY!
Be sure to wear safety glasses when performing the following proce-
dure. Failure to do so can result in serious injury.
To remove the bearing cup from the hub, proceed as follows:
1. Place the hub on a flat work surface with the cup to be removed on the bottom
side.
2. Using a brass drift punch, carefully tap around the small diameter end of the cup
to drive it out.
3. After cleaning the hub bore area, tap in the new cup with the brass drift. Work
gently around the perimeter of the cup so as not to distort it. Make sure that it is fully
seated against the retaining shoulder in the hub.
Maintenance
M
A
I
N
T
E
N
A
N
C
E
CAUTION
!

®
page 18
T-12-T
Maintenance
Standard Bearing Lubrication
Bearings should be lubricated every 12 months or 12,000 miles. If the axles have
been submerged, the bearings should be repacked immediately. Service the bearings
with lithium grease meeting NLGI No. 2 standards. Use this procedure:
1. Place a quantity of grease into the palm of your hand.
2. Press a section of the wide end of the bearing into the outer edge of the grease
pile closest to the thumb, forcing grease into the interior of the bearing.
3. Repeat this while rotating the bearing from roller to roller.
4. Continue this process until you have the entire bearing completely filled with
grease.
5. Before reinstalling the bearing in the hub, apply a light coat of grease on the
bearing cup.
E-Z Lube Bearing Lubrication
If your axles are equipped with the E-Z Lube feature, the bearing can be lubricated
without removing the hubs from the axle. The feature consists of axle spindles that
have been specially drilled and fitted with a grease zerk in their ends. When grease is
pumped into the zerk, it is channeled to the inner bearing and then flows back to the
outer bearings and eventually back out to the grease cap hole. Regrease using this
procedure:
1. Remove the rubber plug from the end of the grease cap.
2. Place a standard grease gun onto the grease zerk located in the end of the
spindle. Make sure the grease gun nozzle is fully engaged on the fitting.
3. Pump grease into the zerk. The old, displaced grease will begin to flow back out
the cap around the grease gun nozzle.
4. When the new, clean grease is observed, remove the grease gun, wipe off any
excess, and replace the rubber plug in the cap.
5. Rotate the hub or drum by hand while adding grease.

®
page 19
T-12-T
Maintenance
Note: The E-Z Lube feature is designed to allow immersion. If the hubs are re-
moved from the axle, it is imperative that the grease seals be replaced. A worn or
defective grease seal will allow brake lining contamination during the bearing greasing
procedure.
Seal Inspection and Replacement
Whenever the hub is removed, inspect the seal to assure that it is not nicked or torn
and is still capable of properly sealing the bearing cavity. If there is any question of its
condition, replace the seal. To replace the seal take the following steps:
1. Pry the old seal out of the hub with a screwdriver. Be careful not to scratch or nick
the sealing surface of the hub with the end of the screwdriver.
2. Clean the hub surfaces. If the bearing is removed for any reason, be sure to
reinstall it before pressing in the new seal. Apply a Permatex sealant to the outside of
the new seal (metal seal shells only).
3. Tap the seal into place using a clean wood block.
Hub Reinstallation and Bearing Adjustment
1. Place the hub (with inner bearing set and grease seal installed), outer bearing,
spindle washer and spindle nut back on the spindle in the reverse order of removal.
Rotate the hub assembly while tightening the spindle nut to approximately 50 lbs.-ft. of
torque.
2. Then loosen the spindle nut to remove the torque. Do not rotate the hub.
3. Finger tighten the spindle nut until just snug.
4. Install a new cotter pin (tang washer for E-Z lube hubs). If necessary, the nut can
be backed off slightly to align the castellations with the cotter pin hole in the spindle.
Bend over the tangs of the pin.
5. Check that the hub turns freely and is without unusual sounds. The spindle nut
should be free to move until restrained by the cotter pin or tang washer.
M
A
I
N
T
E
N
A
N
C
E

®
page 20
T-12-T
2.4 Wheels and Tires
Wheels
Wheels are a very important and critical component of your running gear. Inspect
them visually for cracks or elongated bolt holes whenever they are removed for any
reason. If it becomes necessary to replace the wheels on your trailer, be certain that
the replacement units match the originals in the following regards:
1. Bolt Circle. Many bolt circle dimensions are available and some vary by so little
that it might be possible to attach an improper wheel that does not match the axle hub.
Be sure to match your wheel to the axle hub.
2. Capacity. Be sure your wheels have enough load carrying capacity and pressure
rating to match the maximum load of the tire and trailer.
3. Offset. This refers to the relationship of the center line of the tire to the hub face
of the axle. Care should be taken to match a replacement wheel with the same offset
wheel as originally equipped. Failure to match offset can result in reduced carrying
capacity of your axle.
4. Rim Contour.
RIM CONTOURS!
Use only the approved rim contours as shown in the Tire and Rim
Yearbook or the tire manufacturers catalog. The use of other rim con-
tours is dangerous. Failure to use the proper rim contour can result in
explosive separation of the tire and wheel and could cause a serious
accident.
WHEEL MODIFICATIONS!
Do not attempt to repair or modify a wheel. Even minor modifications
can have a great effect. Do not install a tube to correct a leak through the
rim. If the wheel is cracked, the air pressure in the tube may cause the
pieces of the wheel to explode with great force and can cause serious
injury or death.
Maintenance
DANGER
!
WARNING
!