Braking Systems - Hydraulic

Weak Brakes

Overloaded Trailer

Correct

Malfunctioning
Actuating System

Troubleshoot
System

Brake Adjustment
Not Correct

Manual-Adjust Brakes
Automatic-Make Several
Reverse Stops

Grease or Fluid
on Linings

Replace Shoes
and Linings

Grease or Oil
on Linings

Clean or Replace

Out of Round Drums or
Cracked Drums

Machine or Replace

Harsh Brakes

Surging Brakes

-46-

SYMPTOM

CAUSES

REMEDIES

Underadjustment

Adjust

Lack of Lubrication

Lubricate

Broken Brake
Components

Replace Components

Incorrect Brake
Components

Correct

Loose, Bent or Broken
Brake Components

Replace Components

Underadjustment

Adjust

Out-of-Round Drums

Machine or Replace

Incorrect Tire
Pressure

Inflate Evenly on Both
Sides to Req. Pressures

Unmatched Tires
on Same Axle

Match Tires on Axle

Restricted Brake
Lines or Hoses

Repair or Replace

Malfunctioning Cylinder
Assembly

Check for Stuck
or Sluggish Pistons

Defective or Damaged
Shoe and Lining

Install New Shoe and
Lining-Complete Axle

Noisy Brakes

Locking Brakes

Pulls to One Side

One Side
Out-of-Adjustment

Adjust

Improper Fluid

Replace Rubber Parts
Fill with DOT4 Fluid

Blocked Master
Cylinder

Open with Compressed
Air or Replace Cylinder

Parking Brake
Cable Frozen

Free Cable
and Lubricate

Improper Lining
Thickness or Location

Install New Shoes
and Linings

Dragging

-47-

Braking Systems - Hydraulic

Troubleshooting

Hydtrbl.eps
2/22/94

Hubs/Drums/Bearings

Hubs/Drums/Bearings

Dexter offers several types of bearing arrangements and lubrication methods.
•

Dexter’s standard wheel bearing configuration consists of opposed
tapered roller bearing cones and cups, fitted inside of a precision
machined cast hub. This method of using tapered roller bearings requires
that a minimal amount of axial end play be provided at assembly. This
end play is essential to the longevity of the bearings service life. This
design is typically lubricated with grease, packed into the bearings. Oil
lubrication is another method which is available in some of the larger
axle capacities.

•

E-Z Lube® is another option chosen by some trailer manufacturers. If
your axle is equipped with the Dexter E‑Z Lube® feature, the bearings can
be periodically lubricated without removing the hubs from the axle. This
feature consists of axle spindles that have been specially drilled and
assembled with grease fittings in their ends. When grease is pumped into
the fitting, it is channeled to the inner bearing and then flows back to the
outer bearing and eventually back out the grease cap hole.

•

Nev-R-Lube® option is the latest innovation from Dexter. Nev-R-Lube®
bearings are comprised of opposed tapered roller bearing cones sealed
inside of a precision ground, one piece double cup arrangement. These
bearings are designed with a small amount of axial end play. This end
play is essential to the longevity of the bearings service life. They are
lubricated, assembled and sealed at the factory. No further lubrication is
ever needed.

Before attempting any disassembly of your Dexter axle, make sure you read and
follow the instructions for the appropriate axle type.

Scan to view
Bearing Maintenance video

-48-

Whenever the hub equipment on your axle must be removed for inspection or
maintenance the following procedure should be utilized.
1. Elevate and support the trailer unit per manufacturers’ instructions.

!

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. Remove the wheel.
3. Remove the grease cap by carefully prying progressively around the
flange of the cap. If the hub is an oil lube type, then the cap can be
removed by unscrewing it counterclockwise while holding the hub
stationary.
4. Remove the cotter pin from the spindle nut.
For E-Z Lube® axles produced after February of 2002, a new type of
retainer is used. Gently pry off retainer from the nut and set aside.
5. Unscrew the spindle nut (counterclockwise) 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 will be retained by the
seal.

Brake Drum Inspection
There are two areas of the brake drum that are subject to wear and require
periodic inspection. These two areas are the drum surface where the brake
shoes make contact during stopping and the armature surface where the
magnet contacts (only in electric brakes).
The drum surface should be inspected for excessive wear or heavy scoring. If
worn more than .020" oversized, or the drum has worn out of round by more

-49-

Hubs/Drums/Bearings

Hub Removal - Standard Bearings

than .015", then the drum surface should be re-machined. If scoring or other
wear is greater than .090” on the diameter, the drum must be replaced. When
turning the drum surface, the maximum rebore diameter is as follows:
•
•
•
•
•
•

7" Brake Drum-7.090" diameter
10" Brake Drum-10.090" diameter
12" Brake Drum-12.090" diameter
12 1/4" Brake Drum-12.340" diameter
6K, 7K and 8K Rotor-1.03" minimum thickness
3.5K Rotor-.85" minimum thickness

The machined inner surface of the brake drum that contacts the brake magnet
is called the armature surface. If the armature surface is scored or worn
unevenly, it should be refaced to a 120 micro inch finish by removing not more
than .030" of material. To ensure proper contact between the armature face
and the magnet face, the magnets should be replaced whenever the armature
surface is refaced and the armature surface should be refaced whenever the
magnets are replaced.
Note: It is important to protect the wheel bearing bores from metallic chips
and contamination which result from drum turning or armature refacing
operations. Make certain that the wheel bearing cavities are clean and free
of contamination before reinstalling bearing and seals. The presence of these
contaminants will cause premature wheel bearing failure.

Bearing Inspection

Hubs/Drums/Bearings

Wash all grease and oil from the bearing cone using a suitable solvent. Dry the
bearing with a clean, lint-free cloth and inspect each roller completely.

CAUTION
Never spin the bearing with compressed air.
THIS CAN DAMAGE THE BEARING.

-50-

IMPORTANT: Bearings must always be replaced in sets of a cone and a cup.

!

CAUTION

Be sure to wear safety glasses when removing or installing force
fitted parts. Failure to comply may result in serious eye injury.
When replacing the bearing cup proceed as follows:
1. Place the hub on a flat work surface with the cup to be replaced on the
bottom side.
2. Using a brass drift punch, carefully tap around the small diameter end of
the cup to drive out.
3. After cleaning the hub bore
area, replace the cup by
tapping in with the brass drift
punch. Be sure the cup is
seated all the way up against
the retaining shoulder in the
hub.
Replace only with bearings as specified
in the Bearing Replacement Chart.

-51-

Hubs/Drums/Bearings

If any pitting, spalling, or corrosion is present, then the bearing must be
replaced. The bearing cup inside the hub must be inspected.

Bearing Lubrication - Grease

CAUTION
Do not mix Lithium, calcium, sodium or barium complex greases due
to possible compatibility problems. When changing from one type of
grease to another, it is necessary to ensure all the old grease has
been removed.
Along with bearing adjustment, proper lubrication is essential to the proper
function and reliability of your trailer axle. Bearings should be lubricated every
12 months or 12,000 miles. The method to repack bearing cones is as follows:
1. Place a quantity of grease into the palm of your hand.
2. Press a section of the widest 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.

Hubs/Drums/Bearings

5. Before reinstalling, apply a light coat
of grease on the bearing cup.

Bearing Lubrication - Oil
If your axles are equipped with oil lubricated
hubs, periodically check and refill the hub as necessary with a high quality
hypoid gear oil to the level indicated on the clear plastic oil cap. The oil can be
filled from either the oil fill hole, if present, in the hub or through the rubber plug
hole in the cap itself.

-52-

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
Chem Arrow
Chevron Texaco
Citgo

ConocoPhillips/
76 Lubricants/Kendall
Dexter Company
Exxon/Mobil Company

Fuchs
Great Plains Lubricants
Oil Center Research
of Oklahoma
Pennzoil-Quaker State
Company
Royal Mfg. Company
Shell

Valvoline

Arrow 2282
Chevron Ulti-Plex Grease EP #2
Texaco Starplex Moly MPGM #2
Lithoplex MP #2
Lithoplex CM #2
Mystik JT-6 Hi-Temp Grease #2
Multiplex RED #2
L427 Super Blu Grease
Lithoplex Red MP #2
Ronex, MP
Mobilith AW 2
Mobil I Synthetic Grease
Renolit Uniwrl 2
Lithium Complex EP #2
Liquid-O-Ring No, 167L
Synthetic Red Grease
Royal 98 Lithium Complex EP #2
Gadus S3 V220C
Gadus S5 V220
Rotella Heavy Duty Lithium
Complex #2
Valvoline Multi-Purpose GM
Valvoline DuraBlend

-53-

Hubs/Drums/Bearings

Recommended Wheel Bearing
Lubrication Specifications

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
MFA Oil Company
Mobil Oil Corporation
Phillips 66 Petroleum

Hubs/Drums/Bearings

Pennzoil Products Co.

Oil Center Research
Sun Refining and Marketing
Company
Shell Oil Company

Texaco Oil Company
Troco Division/
Royal Manufacturing
Union Oil Company

Valvoline DuraBlend
CITGO Premium Gear Oil MP
Mystik JT-7
Mystik Power Lube
Universal Gear Lubricant 80W-90
Gear Oil GX 80W-90
Super MP Gear Oil 80W-90
Kendall NS-MP Hypoid Gear Lube
Lubriplate APG 90
Multi-Purpose Gear Oil 80W-90
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
Sunoco Ultra
Sunoco 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

-54-

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 condition, replace the
seal. Use only the seals specified in the
Seal Replacement Chart.
To replace the seal:
1. Pry the seal out of the hub
with a seal removal tool or a
screwdriver. Never drive the seal
out with the inner bearing as
you may damage the bearing.

Bad Seal: Nicks and Tears
(REPLACE SEAL)

2. Apply a sealant similar to PERMATEX® High-Temp Red RTV Silicone
Gasket to the outside of the seal. Use only enough to provide a thin coat
to prevent any excess from contaminating the rubber lip(s) of the seal. It
is okay to apply a slight amount of lube to the inner rubber lip(s) to aid
with installing onto the spindle.
Note: No sealant should be used if the outside of the seal is rubber
coated. For these type of seals it is recommended to apply a thin coat of
oil to the outside rubber.
3. Clean the seal journal of the spindle to inspect for nicks or roughness.
Use a file to remove any burrs from the leading edge or shoulder area.
Clean the journal area with very fine emery cloth. Any presence of deep
gouges or scratches in this area may cause seal failure allowing lubricant
to leak out of the hub.
4, Clean the seal bore in the hub and inspect for any nicks, gouges, or
scratches that may prevent the seal from retaining the bearing lubricant
inside the hub.

-55-

Hubs/Drums/Bearings

Note: The convenient lubrication provisions of the E‑Z Lube® and the oil
lubrication must not replace periodic inspection of the bearings.

5. Orient the seal properly. Many oil bath seals will be marked AIR SIDE on
the side of the seal to facing out of the hub after installation.
6. Install new seal into place using a seal driver or seal installation tool
of proper size. It is important that any seal installation tool contact the
outer ring of the seal casing. If no seal driver is available, use a clean
block of wood. It is critical that the seal be driven in evenly and straight.
NEVER hammer directly on the seal.
7. The seals will be pressed flush to the back surface of the hub in the
600-8,000 lbs. capacity product line. It is NEVER necessary to bottom
out the seal for proper installation. Driving the seal in too deep may
damage the seal and may come in contact with the inner bearing
preventing it from rotating freely.
8. Proper installation will maintain the seal flatness in the hub within .010".
A seal that is cocked too much inside the hub will be more likely to leak.

Bearing Adjustment and Hub Replacement
If the hub has been removed or bearing adjustment is required, the following
adjustment procedure must be followed.
For standard grease or oil axles using cotter pin:
1. After placing the hub, bearings, washers, and spindle nut back on the
axle spindle in reverse order as detailed in the previous section on hub
removal, rotate the hub assembly slowly while tightening the spindle nut
to approximately 50 Ft. Lbs. (12" wrench or pliers with full hand force.)