22,500-27,500 LBS. AXLE CAPACITY

Table of Contents

HEAVY DUTY SERVICE MANUAL

22,500-27,500 LBS. AXLE CAPACITY

Introduction.................................................................3

Maintenance..............................................................15

Important Safety Notice......................................................3
Installation..........................................................................3

Brake Component Lubrication ..........................................15
For camshaft roller journals........................................15
For anchor pins..........................................................15
For manual slack adjusters.........................................15
For automatic slack adjusters.....................................15
Frequency of Service ........................................................15
Suggested Preventative Maintenance................................15
Every 1,000 Miles .....................................................15
Every 12,000 Miles ...................................................15
Every 25,000 to 30,000 Miles ..................................15
Every 100,000 Miles, Once a Year,
or at Brake Reline......................................................15

General Welding Recommendations...............................4
Axle Beam Repair Welding...................................................4
Preheating Recommendations ............................................4
Affects of Welding on Axle Beam Material ...........................4
Welding Guide ....................................................................4
Stress of Axle Beams ..........................................................4
Spring Seat Placement and Location ..................................5
Weld Placement Recommendation for Welding Spring Seats
to Round Axles....................................................................5

Wheel Bearings ............................................................7
Grease Lubrication..............................................................7
Oil Lubrication.....................................................................7
Adjustment.........................................................................7
Recommended Wheel Bearing
Lubrication Specifications...................................................7
Grease:........................................................................7
Approved Grease Sources:...........................................7
Oil:...............................................................................8
Approved Oil Sources:..................................................8

Brake Adjustment Procedure.........................................9
Brake Assembly/Disassembly.....................................10
16½" x 7" Brakes.............................................................10
Disassembly .............................................................10
Reassembly ..............................................................10
12¼" x 7½" Brakes - P Style............................................10
Disassembly...............................................................10
Reassembly ..............................................................11
12¼" x 7½" Brakes - PQ Style..........................................11
Disassembly...............................................................11
Reassembly...............................................................11

Heavy Duty Suspension System (HDSS)........................13
Installation........................................................................13
Alignment.........................................................................13
Measuring.........................................................................13
Adjusting...........................................................................14
Precautions.......................................................................14
Additional Suspension Maintenance Check.......................14
Suspension Torque Requirements......................................14
Torque Values for Bolts .....................................................14

Fastener Specifications..............................................16
Replacement Parts/Kits............................................. 17
Brake Shoe Hardware Kits.................................................17
Brake Block Kits................................................................17
Camshaft Repair Kits.........................................................17
Shoe & Block Assemblies..................................................17

Warranty....................................................................18
Axle Identification......................................................19
Service Record...........................................................20
Notes.........................................................................22
Dexter Video Gallery....................................................24

Introduction
This manual is designed to provide information for you to
understand, use, maintain, and service your trailer running
gear system. Your axles are manufactured by Dexter Axle.
Since 1960, Dexter’s experience in the design, testing,
and manufacturing of trailer axles has resulted in the most
complete product line in the industry. The Dexter running
gear system consists of axles, suspensions, and braking
systems which are engineered to provide you the finest
towing and stopping performance available today.
Two Dexter philosophies are at work to provide you the best
product available and have enabled us to maintain our
position of leadership. First, we operate on the theory that
“there is always a better way” for a product to operate, to
be manufactured, and/or to be serviced. We are constantly
striving to find that better way.
Secondly, we maintain wall-to-wall production control so
that all the major components of your running gear system
are manufactured in Dexter facilities under our strict quality
control standards. These manufactured components include
axle beams, hubs, drums, spindles, and braking systems, as
well as the components used in the attachment of the axle
to the chassis. Dexter has the most complete, state-of-theart manufacturing facilities which enable us to provide you,
the trailer owner, with the finest product possible.
Visit us online at www.dexteraxle.com.

Important Safety Notice
Appropriate service methods and repair procedures are
essential for the safe, reliable operation of all running gear
as well as the personal safety of the individual doing the
work. This manual provides general directions for performing
service and repair work with tested, effective techniques.
Following these guidelines will help assure reliability.

HEAVY DUTY SERVICE MANUAL

22,500-27,500 LBS. AXLE CAPACITY

!

CAUTION

This is the safety alert symbol. It is used to alert you to
potential injury hazards. Obey all safety messages that follow
this symbol to avoid possible injury or death.

Installation
To assure safe operation and maximum durability of parts
such as brake linings and tires, it is necessary to position
and install the axle properly. It is recommended that the
axle assembly be installed so that camshafts rotate in the
same direction as the wheels. Installation in which the
camshaft rotation is opposite that of wheel rotation could
cause noisy brakes, chatter, and wheel “hop”. With this
thought in mind, the axle should be ordered with placement
of air chamber and slack adjuster assemblies that will
ensure the correct directional rotation of the camshafts
when the axle is installed.
It is the responsibility of the axle installer to adjust the
brakes properly. The recommended adjustment procedure is
covered in the section pertaining to brakes.
Responsibility for proper axle alignment lies with the axle
installer. The axle must be installed so that it will be parallel
to the drive axle(s) of the tractor. This will allow good vehicle
control when cornering, longer tire wear, and it will eliminate
dog tracking. Alignment can be determined by measuring
from the center of the trailer king pin to the center of each
end of the axles. The difference should not vary by more
than ¹⁄₁₆". In the case of multiple axles, the axles must
also be in line with each other. The difference between the
centers of one axle and the centers of the other axle must
not vary more than ¹⁄₈".

There are numerous variations in procedures, techniques,
tools, parts for servicing axles, as well as in the skill of the
individual doing the work. This manual cannot possibly
anticipate all such variations and provide advice or cautions
as to each. Anyone who departs from the instructions
provided in this manual must first establish that they neither
compromise their personal safety nor the vehicle integrity by
their choice of methods, tools, or parts.
Refer to your vehicle manufacturer’s owners manual for
additional procedures, techniques, and warnings prior to
performing any maintenance or repairs.
2019.01 | 3

General Welding Recommendations

HEAVY DUTY SERVICE MANUAL

22,500-27,500 LBS. AXLE CAPACITY

Dexter tubular axles are made of high strength steel for
better fatigue life and superior welding qualities. The round
tubular axles provide a uniform section modulus no matter
how the beam is rotated.

center line of the axle beam. Always avoid welds that are
circumferential in nature below the horizontal center line.

Brake spiders are positioned and welded to exacting
specification requirements at our factory. Ring welding the
spider directly to the axle beam provides a higher strength
and more reliable brake attachment over bolt-on versions.

Dexter supplies axles to customers in all stages of assembly
from the beam with spindles only, to the complete axle
assemblies. In the final analysis and with few exceptions,
we have little or no control over later assembly of
incomplete units by the trailer fabricator and, therefore,
we can not be responsible for warranty on improperly
processed components.

In welding suspension component parts to a Dexter trailer
axle, extreme care must be exercised to obtain correct
location and ensure the spring seat load bearing surfaces
are parallel to each other.

Axle Beam Repair Welding
In the interest of safety and preserving the service life of
trailer axle assemblies, Dexter recommends that trailer axle
beams NOT be repair welded. Repair welding can detract
from the structural integrity of an engineered component,
particularly on heat-treated parts where the benefit of the
processing may be nullified by the welding. Therefore, a new
replacement beam should be installed as soon as possible.

Welding Guide

Stress of Axle Beams
The main loaded stresses on a beam are expressed as
three primary stress zones. The compression stress zone
(top side), the tension stress zone (bottom side), and the
neutral stress zone (front and rear horizontal center line
commonly referred to as the neutral axis).

Preheating Recommendations
Absolutely no welding should be done on axles that are
below 50°F. Before welding on suspension components
or any other part onto the axle, the area (within 3") of the
attachment point should be warmed slowly to between
500-600°F. Immediately after checking the temperature
with an appropriate temperature sensitive crayon, the
part(s) should be tack welded in place. Recheck the
temperature and if below 475°F, reheat to 500-600°F and
complete welding per welding instructions.

Affects of Welding on
Axle Beam Material
All welds made on the beam create, in effect, an extremely
localized heat-treatment of the metal. The heat generated
during the welding process can cause the material in the
HAZ (heat affected zone) to become hardened or brittle.
This effect can impart an undesirable characteristic to
the normally ductile structure. This small hardened area
becomes the weakest part of the beam and therefore is
the area most susceptible to failure. The axle beam is
no stronger than its weakest section. As evident from the
sketch on the next page, the welds should be horizontal
and as near as possible to the front and rear horizontal

The above is a graphic representation of the degrees of
stress in the wall of the tube when the beam is under load.
The length of the arrows “X” represents the amount of stress
at a given point. From this illustration, it is evident that the
two opposite stresses diminish as the horizontal center line
of the beam is approached.
In addition, the torsional stress imparted by braking action
of the wheels is taken into consideration in rating the axle
capacity. An allowance of both stresses bending (beam
load) and torsional are factored into the calculations to
provide an acceptable design factor. The stresses are
reapplied and reversed many times during normal axle
beam life. For this reason, the beam material must have
certain properties such as impact strength, that permit it to
absorb shock, to flex, and then to resume its original and
normal “as manufactured” condition.
When welding, it is necessary to avoid the high stress areas
on the tube top side (compression zone) and tube bottom
side (tension zone). All welds should be made as close to
the horizontal center line as possible. When the axle tube is
2019.01 | 4

General Welding Recommendations

subjected to the heat from welding and then rapid cooling,
the material adjacent to the weld loses it’s desirable ductile
properties and becomes brittle. If this condition exists in the
high stress areas under maximum load conditions, the life
of the axle will be greatly reduced and premature fatigue
failure can occur. Recommended locations for the welds are
shown below.

HEAVY DUTY SERVICE MANUAL

22,500-27,500 LBS. AXLE CAPACITY

Weld Placement Recommendation for
Welding Spring Seats to Round Axles
Note: If spring seat and related U-bolt clamp parts are
different than shown, refer or consult with suspension
manufacturer for weld recommendations.

Spring Seat Placement and Location
One of the most critical and important phases of vehicle
fabrication is the placement, location, and attachment of
spring seats on the axle.
“Overhang” is defined as axle track minus spring center
dimension divided by two:
T - S.C.
2
The maximum spring center is calculated such that
recommended inside of tire or drum clearance to vehicle
frame is achieved.
Permanent deformation and/or premature failure of the axle
may result if the spring centers are too narrow.

The welding rods should conform to AWS (American Welding
Society), grade E-7018 (Oven-Dried) or comparable.
Recommended rod size is ⁵⁄₃₂" at voltage and amperage
recommended by the electrode manufacturer. For maximum
strength, a three-pass weld should be used. The arc should
not be broken at the end of each pass and the corners should
be wrapped. The electrode should be backed up to fill in the
crater at the end of each pass. If the arc is broken between
passes, thoroughly clean the weld between each pass.
2019.01 | 5

General Welding Recommendations
Process
Shielded metal-arc welding of
carbon and low alloy steels.
Gas metal-arc welding of carbon
and low alloy steels.
Submerged arc welding of mild
and low alloy steels.

HEAVY DUTY SERVICE MANUAL

22,500-27,500 LBS. AXLE CAPACITY

Electrode
A.W.S.* E70XX
A.W.S.* ER70S-X
A.W.S.* F-72-XXXXX

*American Welding Society

CAUTION
Do not bring axles in from non-heated storage and weld while
cold. Do not “test the arc” on the axle beam.

Fillets up to ¹⁄₂" can be used. Maximum gap .030 inch.
The attachments should fit-up as close to the beam as
possible to avoid excessive welding. Electrical grounding to
the axle for welding purposes, should be done on one of the
attachments such as the air chamber bracket, cam support,
or brake spider. Connections should be clean and tight.
Loose or dirty connections will cause arcing at that point
during welding. These small arced areas can create the
potential for failure in highly stressed structures. Therefore,
grounding should never be done directly on the axle tube.
Never attach the ground to an area that would allow the
ground path to pass through the spindles, bearings, hub, or
wheel components.

CAUTION
To provide optimum suspension-to-tube welds, preheating is
recommended. Preheating will minimize loss of the ductile
properties in the weld area by slowing the rate of cooling,
thus reducing the formation of an untempered martensitic
grain structure adjacent to the weld. Martensite, a brittle
grain structure, is formed by the rapid cooling of the metal
surrounding the weld area. Preheat the suspension seat weld
area to 500-600°F prior to welding. Preheated temperature
should be verified with a temperature sensitive crayon or
appropriate means.

The above welding recommendation pertains to all Dexter
Axle Company axle beams. Unapproved variation from the
procedures listed will void the axle warranty and could
result in an unsafe weld.

2019.01 | 6

Wheel Bearings
Periodic inspection and regular replacement of lubricant is
important to obtain maximum bearing life. Always inspect
bearings for damage prior to installation. When installing
wheel bearings, it is important to ensure both the inside of
the wheel hub cavity, bearings and grease cap are clean. It
is also recommended that seals be replaced when wheel
hubs have been removed for service. EXTREME CARE
SHOULD BE TAKEN WHEN REINSTALLING WHEEL HUBS
TO PREVENT DAMAGE TO THE SEALS. DO NOT CONTACT
RUBBER SEALING LIP WITH THE SPINDLE THREADS.

Grease Lubrication
Grease should be replaced every 12,000 miles or 12
months. Prior to repacking bearings, all old grease should
be removed from the wheel hub cavity and bearings.
Bearings should be packed by machine. If machine is
unavailable, packing by hand method is acceptable. The
method to pack bearing cones is as follows:
1. Place a quantity of grease onto
the palm of your hand.
2. Press a section of the widest
end of bearing into the outer
edge of the grease pile closest
to the thumb, forcing grease
into the interior of the bearing
between two adjacent rollers.
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, apply a light coat of grease onto
the bearing cup mating surface.

Oil Lubrication
Oil should be changed at least once a year, or 100,000
miles, or whenever the seals or brakes are replaced. Oil
level should be inspected every 1,000 miles. Always allow
a few minutes, after adding oil or after vehicle operation, for
the oil to settle when establishing the required oil level.

Adjustment
1. After properly installing the bearings and seals
according to the manufacturer’s recommendations,
tighten the inner spindle nut to 100 Ft. Lbs. while

HEAVY DUTY SERVICE MANUAL

22,500-27,500 LBS. AXLE CAPACITY

rotating the hub to ensure proper seating of the
bearings, cups and seal in the wheel hub.

CAUTION

!

You must follow the maintenance procedures to prevent
damage to important structural components. Damage to
certain structural components such as wheel bearings can
cause the wheel end to come off of the axle. Loss of a wheel
end while the trailer is moving can cause you to lose control
and lead to an accident, which can result in serious injury or
death.

2. Loosen the inner spindle nut to remove preload
torque.
3. Hand tighten the inner adjustment nut, then back off
¹⁄₄ turn, ³⁄₈ turn maximum.
4. Install lock ring (lock ring must engage pin on inner
spindle nut. Nut to engage nearest pin hole).
5. Install tab washer and outer locknut. Torque outer
spindle nut to 250-300 Ft. Lbs. Bend 3 tabs over
outer nut flats to secure.
6. This procedure should assure an end-play of .001" to
.010" which must be present in the adjusted wheel
bearing assembly.

Recommended Wheel Bearing
Lubrication Specifications
Grease:
Thickener Type
Dropping Point
Consistency
Additives
Viscosity Index

Lithium Complex
215°C (419°F) Minimum
NLGI No. 2
EP, Corrosion & Oxidation Inhibitors
80 Minimum

Approved Grease Sources:
76 Lubricants Company
Citgo Petroleum Corp.
Exxon Company, USA
Kendall Motor Oil
(Div. of Witco Corp.)

76 Multiplex EP
76 Multiplex RED
Lithoplex MP #2
Lithoplex CM #2
Ronex, MP
Kendall Super Blu L427
Grease

2019.01 | 7

Wheel Bearings
Mobil Oil Company

Mystik Oil Company Inc.

Oil Center Research
of Oklahoma
Pennzoil-Quaker State
Company
Shell

Royal Mfg. Company
Chevron Texaco

Chem Arrow Corp.
Valvoline
(Div. of Ashland Inc.)
Great Plains Lubricants

Mobil Grease HP
Mobilith AW 2
Mobil I Synthetic Grease
Mystik JT-6 Hi-Temp Grease
Red Lithium Complex EP No. 2
Mystik SX-6 Synthetic Blend
Extreme
Range, Low Temp Blue Lithium

Complex
Liquid-O-Ring No, 167L

HEAVY DUTY SERVICE MANUAL

22,500-27,500 LBS. AXLE CAPACITY

MFA Oil Company
Mobil Oil Corporation
Phillips 66 Petroleum

Pennzoil Products Co.

Synthetic Red Grease
Gadus S3 V220C
Gadus S5 V220
Rotella Heavy Duty Lithium
Complex #2
Royal 98 Multi-Lube EP #2
Lithium
Complex
Chevron Ulti-Plex Grease EP
NLGI 2
Texaco Starplex Moly MPGM 2
Arrow 78981-1
Valvoline Multi-Purpose GM

Oil Center Research
Sun Refining and
Marketing Company
Shell Oil Company

Texaco Oil Company
Troco Division /
Royal Manufacturing
Union Oil Company

Multi-Purpose Gear Oil 80W90
Mobilube SHC
Mobil 1 Synthetic Gear Lube
Superior Multi-Purpose Gear
Oil
Philguard Gear Oil
Philsyn Gear Oil
Gear Plus 80W-90 GL-5
Gear Plus Super 75W-90
Gear Plus Super EW 80W-90
Multi-Purpose 4092 Gear Lube
Liquid-O-Ring 750 GX
Sonoco Ultra
Sonoco Dura Gear
Spirax A
Spirax G
Spirax HD
Spirax S
Multigear EP
Multigear SS
Multigear Select Gear Oil
Unocal MP Gear Lube
76 Triton Syn Lube EP

Lithium Complex EP Grease
NLGI 2

Oil:
SAE 90, SAE 80W-90, SAE 75W-90

Approved Oil Sources:
Ashland Oil
CITGO Petroleum Co.

Conoco
Exxon Company USA
Industrial Oils Unlimited
Kendall Refining Co.
Lubriplate Division /
Fiske Brothers Refining

Valvoline Dura Blend
Valvoline Power Lube
CITGO Premium Gear Oil MP
Mystik JT-7
Mystik Power Lube
Universal Gear Lubricant 80W90