INSTALLATION INSTRUCTIONS
Vented Disc Brake

IMPORTANT: READ AND UNDERSTAND THE ENTIRE
INSTRUCTION/ASSEMBLY PROCEDURE BEFORE INSTALLATION.

When backing a trailer with disc brakes, you must have a lockout lever or
preferably an electrically operated solenoid to stop brake pressure to the
disc brakes. The solenoid is mounted at the rear of the actuator, between
the master cylinder and brake line. It has a wire connected to your back
up lights to stop or redirect the fluid to keep the brakes from operating.

Vented rotor disc brakes are designed to activate when the vehicle’s
brakes are applied. As the vehicle stops or slows, the momentum of
the trailer pushes forward, developing pressure in the actuator (master
cylinder), which is used to apply pressure to the brakes.

Replace Brake Pads

Check your trailer frequently for any leaks in the hydraulic system, which
includes the actuator, brake lines and brakes.
The brake rotors are made of iron and will show surface rust on the
braking surface when not used for a week or more. Normal use will wipe
the rust off of the rotor surface. If the trailer is used in salt water, it is
recommended that you rinse off the brakes with fresh water after each
use to reduce the effects of saltwater corrosion.
Your trailer should tow easily. Disc brakes operate at a higher
temperature than drum brakes. This is normal and is very similar to the
way disc brakes operate on your vehicle. If for any reason your trailer
does not tow easily or wants to veer to one side, stop and investigate
immediately and solve the problem.

1.

Elevate the trailer using the manufacturer’s instructions. Always use
jack stands for support. Do not depend on a jack to support the
trailer. Block wheels to keep trailer from rolling.

2.

Remove the tire/wheel assembly. Inspect the rotor surface. Check
for excessive wear or grooves that may affect braking. Original hat
style rotor thickness is .939” with a minimum thickness of .85” or
21.6 mm. Original integral rotor thickness is .75” with a minimum
thickness of .67” or 17 mm.

3.

Inspect brake pads. Minimum thickness is 3/32”. Pads should be
replaced if below this width.

4.

Remove the caliper by unscrewing the slider pins from the mounting
bracket. Be careful to hold the caliper in place so that it does not fall
and pull on the brake hose. The inside pad is spring loaded in the
caliper piston. Pry this pad out gently with a flat blade screwdriver.
The outside pad is held in place with two metal tabs. Use a large pair
of pliers to straighten the tabs to remove the outside pad.

5.

Clean the rotor with a brake cleaning spray. Replace brake pads in
reverse order. The tabs should only be bent enough to hold the pad
in place. Do not bend tab too far or the pad will not seat correctly.
Outside pad should be able to wiggle after tab is bent.

6.

Clean threads on slider bolts and mounting plate. Apply a coating
of LIQUID LOCTITE® 263 or equivalent to the internal threads of
the mounting bracket only. Insert slider pins through backside of
caliper into mounting bracket. Use a 7/16” hex socket and tighten
both pins to 40 ft. lbs.

Towing a trailer (even a trailer with brakes) puts an added load on
the tow vehicle’s handling and braking capabilities. Do not follow too
closely; you will need extra distance to maneuver and to stop.
Towing downhill puts added stress on both the tow vehicle and the trailer.
Slow down before you start on an incline and maintain a controlled
downhill speed with repeated application of brakes followed by a cooling
period when brakes are not applied. It is very important to start off with a
slow speed and maintain it rather than trying to slow down from a higher
speed. Should you feel the brakes on the trailer or tow vehicle are running
hot or showing signs of fade, stop immediately on the side of the road
and allow the brakes to cool before resuming your trip.
Should you feel the tow vehicle and trailer brakes are not working as
they should, have the tow vehicle and trailer inspected. Make sure your
trailer’s Gross Vehicle Weight (GVW) is within the tow vehicles capacity.
If your trailer has multiple axles, verify that the GVW of the trailer does
not exceed the capacity of the brakes, which is 3750 lbs on 10” (5
lug) brakes and 6000 lbs on 12” (6 lug) brakes, per axle. Some states
require brakes on all axles. Check with your state laws and the state
laws of where you will be using your trailer.

DO NOT REASSEMBLE WITHOUT APPLYING LIQUID LOCTITE® TO
THE BACKING PLATE. SLIDER PINS COULD BACK OUT AND CAUSE
PERMANENT DAMAGE TO YOUR BRAKES AND TRAILER.
1.

After long trips or downhill towing, let brakes cool down before
submerging in cold water. The change in temperature of hot brakes
submerged in water creates additional stress on the parts and could
cause damage to them.

If your axle has an integral style rotor, then the hub and rotor are
one piece, and will come off as one.

2.

If you have a hat style rotor, the rotor will be removed after the
wheel and caliper are removed. The hub will come off separate.

3.

Elevate the trailer using the manufacturer’s instructions. Always use
jack stands for support. Do not depend on a jack to support the
trailer. Block wheels to keep trailer from rolling.

4.

Remove the tire/wheel assembly.

5.

Remove the caliper by unscrewing the slider pins from the

Removing Hub/Rotor

Replace pads when the friction material is 3/32” or less. Original Dexter
brake pads have a GalvX coated backing plate that aids in corrosion
resistance.
Use DOT 3 brake fluid only. DO NOT USE SILICONE BASED BRAKE FLUID.
©2019 Dexter Axle Company | www.dexteraxle.com

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059-Z00-98 2019.09 | 08242

mounting bracket. Be careful to hold the caliper in place so that
it does not fall and pull on the brake hose. Support the caliper so
that it does not “hang” from the brake line.
6.

Remove the grease hat from the hub by prying around the edge of
the cap.

7.

Bend the locking tang washer to the “free” position. If spindle is
equipped with a cotter key, straighten cotter key to remove.

8.

Remove the spindle nut in a counter clockwise direction and
remove the spindle washer.

9.

Remove the hub from the spindle. Be careful not to allow bearings
to fall out of the hub.

rotor”, install rear bearing and seal. Grease bearings, then install
front bearings.

Step 4

10. Clean bearing and cup surfaces, repack with lithium marine grade
grease.
11. Place hub on spindle in reverse order as listed above. Rotate the
hub while tightening the spindle nut to approximately 50 ft. lbs.
This translates into full hand pressure with a 12” long set of pliers
or 12” long wrench.

Step 4a

5.

Place caliper over rotor and mounting plate. A bleeder valve must
be in the up position (see below). Check both calipers for this
position. Some calipers have two valves others have only one.

6.

Apply a coating of LIQUID LOCTITE® 263 or equivalent to threads
on the mounting plate. Insert slider pins through backside of
caliper into mounting plate. Use a 7/16” hex socket and tighten
both pins to 40 ft. lbs. Check for binding, make sure rotor spins
freely. NOTE: If the pins are removed after step 6, the pins/
mounting bracket threads must be cleaned. Apply LOCTITE® 263 to
the internal threads of the mounting bracket only. Be careful not to
get LOCTITE® on slider pins or bushings.

12. Loosen the spindle nut to remove the torque, do not rotate hub.
13. Finger tighten the spindle nut until snug, backing out only to line
up the locking tang washer. Bend the locking tang tab in place,
Replace rotor.

Step 5

14. Clean threads on slider bolts and mounting plate. Apply a coating
of LIQUID LOCTITE® 263 or equivalent to the internal threads of the
mounting bracket only. Tighten bolts to 40 ft. lbs.
DO NOT REASSEMBLE WITHOUT APPLYING LIQUID LOCTITE® TO
THE BACKING PLATE. SLIDER PINS COULD BACK OUT AND CAUSE
PERMANENT DAMAGE TO YOUR BRAKES AND TRAILER.
15. Replace cap. Install tire/wheel assembly and tighten wheel nuts
to trailer manufacturer specifications. Test wheel for excessive
tightness or excessive play. Readjust if necessary. Road test vehicle
in a safe place before traveling on main roads in traffic.

Step 6

7.

Installation/Replacement Instructions for Vented Disc Brakes
1.

If installation is on a completed trailer, remove tire/wheel. This
would be a good time to repack wheel bearings and inspect the
bearings and seals if it has not been done recently.

3.

Install hub (use existing instruction on installing hubs).
Step 1

4.

IMPORTANT: WHEN BLEEDING CALIPERS, ALWAYS USE THE TOP MOST
BLEEDER VALVE TO ALLOW AIR TO ESCAPE FROM THE CALIPER PISTON

On a bare axle attach mounting plate to brake flanges with
the bleeder in the upright position. Exact positioning will be
determined by the brake flange. Use 7/16” x 1-1/4” zinc hex bolts,
lock nuts/washers and torque to 40 ft. lbs. Note: brake mounting
plates can have 2 or 4 holes for attaching to the axle.

2.

Connect brakes lines and bleed brakes before using.

Always bleed through the
upper most bleeder valve.

Step 3

Place hat style rotor over hub. Make sure the hub face is clean
with a smooth surface or: If installing an integral or “one piece hub

©2019 Dexter Axle Company | www.dexteraxle.com

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059-Z00-98 2019.09 | 08242