CHAPTER 32
Disc Brake System
Removing and Inspecting Calipers
32-1
Research the procedure for
removing the caliper in the
appropriate service
information. Loosen the
bleeder screws slightly and
then retighten them.
Removing and Inspecting Calipers
32-1
If the caliper is being rebuilt
or a new caliper will be
installed, it is good practice
to flush the old brake fluid
from the system at this time.
Removing and Inspecting Calipers
32-1
Use a brake pedal holding
tool to slightly apply the
brakes and block off the
compensating ports in the
master cylinder to avoid
excess fluid leakage.
Removing and Inspecting Calipers
32-1
Remove the brake line or
hose from the caliper. Be
careful not to lose the
sealing rings.
Removing and Inspecting Calipers
32-1
Push the caliper pistons
back into their bores
slightly. While many use a
screwdriver as shown, a pry
bar is a safer choice.
Removing and Inspecting Calipers
32-1
Remove the caliper
assembly from its
mountings.
Removing and Inspecting Calipers
32-1
Inspect the caliper for leaks
or damage, including the
piston dust boot. Determine
any necessary actions.
Inspecting Caliper Mountings,
Slides, and Pins
32-2
Clean the caliper mountings
and slides/pins using
equipment/procedures for
dealing with
asbestos/hazardous dust.
Inspecting Caliper Mountings,
Slides, and Pins
32-2
Inspect the caliper
mountings and slides/pins
for wear and damage.
Determine any necessary
actions.
Inspecting Brake Pads and Wear
Indicators
32-3
Determine the type of wear
indicator system utilized.
Check that it is not
contacting or nearly
contacting the rotor.
Inspecting Brake Pads and Wear
Indicators
32-3
If the system is a sensor
style, test the system to
verify that the system is
operational. Determine any
necessary actions.
Checking Brake Pads
32-4
Remove the pads and
retaining hardware. Inspect
all pads, retaining
hardware, and anti-noise
shims for wear or damage.
Checking Brake Pads
32-4
Measure the remaining
brake pad thickness and
compare to specifications.
Determine any necessary
action(s).
Disassembling Calipers
32-5
Disassemble the caliper,
following the service
manual procedure.
Disassembling Calipers
32-5
Clean all of the caliper parts
following the service
manual procedure.
Disassembling Calipers
32-5
Inspect each of the parts for
damage, rust, and wear.
Disassembling Calipers
32-5
Measure the caliper boreto-piston clearance with a
feeler gauge and compare
to specifications. Determine
any necessary actions.
Reassembling Calipers
32-6
Make sure the rotor has
been properly installed on
the hub/spindle and the hub
surface is free of rust or dirt.
Reassembling Calipers
32-6
Reassemble the caliper
assembly, following the
manufacturer’s procedure.
Reassembling Calipers
32-6
Assemble the pads,
hardware, and caliper on
the caliper mountings using
the specified lubricant.
Lubricate all moving parts.
Reassembling Calipers
32-6
Reinstall the brake line
fittings using two new
copper washers
(if equipped).
Reassembling Calipers
32-6
Tighten the brake line fitting
and caliper bolts to the
proper torque. Bleed the
brakes following the
manufacturer’s procedure.
Reassembling Calipers
32-6
Seat the pads by applying
the brake pedal several
times, not allowing the
pedal to go all the way to
the floor.
Reassembling Calipers
32-6
If the brake pedal is spongy,
you will need to bleed the
brakes of any remaining
trapped air in the system.
Reassembling Calipers
32-6
Inspect the system for any
brake fluid leaks, no matter
how small.
Retracting and Readjusting Pistons
on an Integrated Parking Brake
32-7
Research the procedure for
retracting the caliper piston.
Select the proper adapter or
tool to match the caliper
piston.
Retracting and Readjusting Pistons
on an Integrated Parking Brake
32-7
Install the tool and turn it in
the direction that causes the
piston to retract.
Retracting and Readjusting Pistons
on an Integrated Parking Brake
32-7
Continue turning until the
piston is lightly seated at
the bottom of its bore.
Retracting and Readjusting Pistons
on an Integrated Parking Brake
32-7
Make sure the dust boot is
seated properly in its
grooves.
Inspecting and Measuring Disc
Brake Rotors
32-8
Research the procedure
and specifications for
inspecting the rotor. If you
have not already done so,
remove the caliper
assembly, brake pads, and
any hardware. Clean the
rotor with approved
asbestos removal
equipment.
Inspecting and Measuring Disc
Brake Rotors
32-8
Inspect the rotor for hard
spots or hot spots, scoring,
cracks, and damage.
Inspecting and Measuring Disc
Brake Rotors
32-8
Measure the rotor thickness
at the deepest groove or
thinnest part of the rotor
and compare to
specifications.
Inspecting and Measuring Disc
Brake Rotors
32-8
Measure the thickness of
the rotor in a minimum of
five to eight places around
the face of the rotor.
Calculate the maximum
thickness variation and
compare to specifications.
Inspecting and Measuring Disc
Brake Rotors
32-8
Set up a dial indicator to
measure lateral runout.
Rotate the rotor and find the
lowest spot on the rotor,
then zero the dial indicator.
Inspecting and Measuring Disc
Brake Rotors
32-8
Slowly rotate the rotor to
find the highest spot on the
rotor. Read the dial
indicator showing maximum
runout.
Inspecting and Measuring Disc
Brake Rotors
32-8
Keep turning the rotor to make
sure the dial indicator does not
read below zero. If it does,
rezero the dial caliper on the
lowest spot. Keep turning the
rotor to find the highest spot
and reread the dial indicator.
Compare all of your readings to
the specifications and determine
if the rotor is fit for service, is
machinable, or needs to be
replaced.
Removing and Reinstalling Rotors
32-9
Research the procedure for
removing and reinstalling
the brake rotor. If you have
not already done so,
remove the caliper
assembly, brake pads, and
any hardware. If the caliper
mount straddles the rotor,
remove it.
Removing and Reinstalling Rotors
32-9
To remove the hublessstyle rotor, mark the rotor
for proper reinstallation.
Removing and Reinstalling Rotors
32-9
If there are screws or speed
nuts holding the rotor to the
hub, remove them.
Removing and Reinstalling Rotors
32-9
Remove the rotor from the
hub.
Removing and Reinstalling Rotors
32-9
To remove the hub-style
rotor, remove the wheel
bearing locking mechanism.
Removing and Reinstalling Rotors
32-9
Remove the wheel bearing
adjusting nut, thrust washer,
and outer bearing.
Removing and Reinstalling Rotors
32-9
Follow the steps of the inner
bearing and grease seal
removal procedure if the
rear bearing must be
removed.
Removing and Reinstalling Rotors
32-9
To reinstall a hubless-style
rotor, clean all mounting
surfaces on the hub and
rotor and remove any burrs.
Removing and Reinstalling Rotors
32-9
Slip the rotor over the wheel
studs.
Removing and Reinstalling Rotors
32-9
If the rotor uses small
screws to hold the rotor to
the hub, reinstall those and
tighten to the proper torque.
Removing and Reinstalling Rotors
32-9
Spin the rotor to ensure it
spins true and does not
contact any other
components such as the
dust shield.
Removing and Reinstalling Rotors
32-9
To reinstall a hub-style
rotor, see the wheel bearing
service skill drills in the
Wheel Bearing chapter. Be
sure to properly lock the
adjustment nut in place
once adjustment is
completed.
Removing and Reinstalling Rotors
32-9
Spin the rotor to ensure it
spins true and does not
contact any other
components such as the
dust shield.
Refinishing Hubless Rotors on
Vehicle
32-10
Research the brake lathe
manufacturer’s procedure
for properly refinishing the
rotor. Mount the on-car
brake lathe to the rotor after
cleaning the rust and dirt
from between the rotor and
hub or adjusting the wheel
bearing so there is no end
play.
Refinishing Hubless Rotors on
Vehicle
32-10
Perform the runout
calibration on the brake
lathe.
Refinishing Hubless Rotors on
Vehicle
32-10
Adjust the cutting bits and
cut off any lip at the edge of
the rotor.
Refinishing Hubless Rotors on
Vehicle
32-10
Make sure the cutting bits
will not contact the rotor
face, and move the cutting
head toward the inner
diameter of the rotor face.
Set the cutting bits to the
proper cutting depth for
machining.
Refinishing Hubless Rotors on
Vehicle
32-10
Install the anti-chatter
device, if specified.
Refinishing Hubless Rotors on
Vehicle
32-10
Engage the automatic feed
and watch for proper
machining action. If
necessary, repeat this step
until all damaged surface
areas have been removed
on both sides of the rotor.
Refinishing Hubless Rotors on
Vehicle
32-10
If necessary, perform a
finish cut on the rotor.
Refinishing Hubless Rotors on
Vehicle
32-10
Remeasure the rotor
thickness to determine if the
rotor is above minimum
thickness specifications.
Refinishing Rotors off Vehicle
32-11
Research the brake lathe
manufacturer’s procedure
for properly refinishing the
rotor. Clean nicks, burrs, or
debris from the mounting
surfaces of the rotor
including the centering hole.
Refinishing Rotors off Vehicle
32-11
Mount the rotor. Check that
the rotor is running true on
the lathe.
Refinishing Rotors off Vehicle
32-11
Install the anti-chatter band
or anti-chatter pucks on the
rotor.
Refinishing Rotors off Vehicle
32-11
Position the cutting head
about one-quarter the way
in from the outer diameter
of the rotor. Turn on the
lathe.
Refinishing Rotors off Vehicle
32-11
Set the cutting bits to the
proper cutting depth for
machining the ridge.
Refinishing Rotors off Vehicle
32-11
By hand, move the cutting
head outward toward the
ridge. Slowly remove the
ridge.
Refinishing Rotors off Vehicle
32-11
Once the ridge is removed,
run the cutting head all the
way in to the inner face of
the rotor.
Refinishing Rotors off Vehicle
32-11
Set the cutting bits to the
proper cutting depth for
machining the rotor face.
Refinishing Rotors off Vehicle
32-11
Engage the automatic feed
on “fast” cut and watch for
proper machining action.
Some single-cut machines
only have one cutting
speed. If necessary, repeat
this step until all damaged
surface areas have been
removed on both sides of
the rotor.
Refinishing Rotors off Vehicle
32-11
If necessary, perform a
finish cut on the rotor. This
is usually done on “slow”
speed.
Refinishing Rotors off Vehicle
32-11
Use sandpaper or a drill
with a sanding pad to give
the rotor faces a
nondirectional finish.
Refinishing Rotors off Vehicle
32-11
Remeasure the rotor
thickness to determine if the
rotor is above minimum
thickness specifications.
Inspecting and Replacing Wheel
Studs
32-12
Inspect the wheel studs and
lug nuts for damage. Look
for signs of stretched studs,
cross-threaded lug nuts,
and broken-off studs.
Determine if the stud can be
removed with the flange on
or off the vehicle.
Inspecting and Replacing Wheel
Studs
32-12
To perform the drawing-in
method, position the flange
so the stud has clearance
on the back side to be
removed.
Inspecting and Replacing Wheel
Studs
32-12
Remove any damaged
studs with a hammer. Be
careful not to damage any
of the surfaces on the
flange and hub, including
the wheel speed sensor and
tone ring.
Inspecting and Replacing Wheel
Studs
32-12
Insert the stud in the hole in
the flange and rotate it so
that all of the flutes on the
stud line up with the
notches in the flange.
Inspecting and Replacing Wheel
Studs
32-12
Place enough heavy-duty
washers over the stud to
prevent the lug nut from
bottoming out on the
threads.
Inspecting and Replacing Wheel
Studs
32-12
Place the lug nut onto the
stud, flat side in. Tighten it
until the stud bottoms out in
the flange. Inspect the
threads on the stud and lug
nut to make sure they did
not get damaged.
Inspecting and Replacing Wheel
Studs
32-12
To perform the hydraulic
press method, remove the
hub and wheel flange from
the vehicle following the
manufacturer’s procedure.
Inspecting and Replacing Wheel
Studs
32-12
Use the press to push out
any damaged lug studs.
Inspecting and Replacing Wheel
Studs
32-12
Insert the new lug stud into
the wheel flange hole. Line
up the flutes on the stud
with the notches in the
flange.
Inspecting and Replacing Wheel
Studs
32-12
Support the hub and flange
so the press is pushing the
stud straight into the flange.
Inspecting and Replacing Wheel
Studs
32-12
Push the stud in until it
bottoms out in the flange.
Inspecting and Replacing Wheel
Studs
32-12
To complete the drawing-in
method and the hydraulic
press method, verify that
each stud is fully seated in
the flange.
Inspecting and Replacing Wheel
Studs
32-12
Reinstall the hub and flange
on the vehicle if it was
removed.
Installing Wheels, Torquing Lug
Nuts, and Making Final Checks
32-13
Start the lug nuts on the
wheel studs, being careful
to match up the surfaces.
Installing Wheels, Torquing Lug
Nuts, and Making Final Checks
32-13
Carefully run all of the lug
nuts down so they are
seated in the wheel.
Installing Wheels, Torquing Lug
Nuts, and Making Final Checks
32-13
Lower the vehicle so the
tires are partially on the
ground to keep them from
turning while tightening the
lug nuts.
Installing Wheels, Torquing Lug
Nuts, and Making Final Checks
32-13
Use a torque wrench to
tighten each lug nut to the
proper torque in the proper
sequence.
Installing Wheels, Torquing Lug
Nuts, and Making Final Checks
32-13
Once all of the lug nuts
have been torqued, go
around them again, this
time in a circular pattern to
ensure that you did not miss
any in the previous pattern.
Installing Wheels, Torquing Lug
Nuts, and Making Final Checks
32-13
If the vehicle was equipped
with hubcaps and valve
stem caps, reinstall them.
Installing Wheels, Torquing Lug
Nuts, and Making Final Checks
32-13
Check the brake fluid level
in the master cylinder
reservoir. Start the vehicle
and check the brake pedal
for proper feel and height.
Check the parking brake for
proper operation. Also
inspect the system for any
brake fluid leaks and loose
or missing fasteners.