Calipers with Service-Only Chambers
Do BOTH the pads AND rotor have bright red
dust and/or white residue? **Since it is possible
that the caliper may have been replaced after a
previous high level of heat event on this rotor,
the intent is to confirm that both the caliper and
the pads have experienced a high level of heat.**
(This assumes that the pads would have been
replaced at the same time the caliper was replaced
due to a prior high level of heat). – YES/NO
RED or WHITE Pads

NO

PASS

RUNNING
CLEARANCE
QUICK
INSPECTION

YES

Calipers without parking brake actuator (i.e., steer, tag, pusher)

Do any other brake pads
OR rotors on the vehicle
have bright red dust OR
white residue?
– YES/NO

Inspect all hoses, caps,
covers, and the brake
exterior for damage or
kinks (check at full left
and right steering lock).
– PASS/FAIL

YES

When both ends of an axle, or multiple brakes on a single vehicle are
affected, a thorough brake system diagnosis is needed, as other factors
– such as brake balance, overloaded vehicles, or extreme use – are
likely the source.

NO

PASS

FAIL

RED or WHITE Rotor

Air Disc Brake OK.

PASS

Inspect all hoses,
caps, covers, and
the brake exterior
for damage or kinks
(check at full left and
right steering lock).
– PASS/FAIL

Replace components as
needed with genuine
Bendix® parts.
PASS

CAUTION: FOLLOW ALL
SAFE MAINTENANCE
PRACTICES.
On level ground, with the wheels
chocked and the parking brake
temporarily released, verify
there is sufficient running
clearance between the pads.
Using hand pressure only
(no tools), check for inboard/
outboard movement of the
brake caliper. Small movement
of less than 0.08 in. (2 mm) –
approximately the thickness of
a nickel – indicates that there
is sufficient running clearance
and the caliper is sliding freely.
For a more accurate reading,
a dial indicator may be used
to measure running clearance.
The recommended running
clearance range is 0.0240.047 in. (0.6-1.2 mm). Fail if
the caliper movement or running
clearance are unable to be
confirmed. – PASS/FAIL

FAIL

Remove the wheel and push the caliper
assembly inboard on its guide pins. Note: To
fully release the spring brakes, ensure that the
air system pressure is at least 90 psi. Using
a suitable tool (for example a short pry bar),
press the inboard pad away from the tappets.
Check that there is no dirt, etc. in the gap, and
clean if necessary. Then use two long-blade
feeler gauges to measure – over the whole
tappet surface – the gap between them and
the inboard pad backplate. (See Figure 16.)
The gap should be between 0.024 in. (0.6 mm)
and 0.047 in. (1.2 mm). PASS if the gap is
within the given range. – PASS/FAIL

YES
PASS

Can both inboard and
outboard pads be removed
from the caliper by hand?
– YES/NO

FAIL
Pull
Caliper
Inboard

Figure 15 – Pull Caliper Inboard

PASS (within
0.6-1.2 mm tolerance)

Remove the actuator to
inspect the caliper and
actuator internals for
corrosion. Confirm the
caliper lever applies and
fully releases smoothly by
manually cycling the
lever with a screwdriver.
– PASS/FAIL
FAIL

PASS

FAIL

Replace
components
as needed
with genuine
Bendix® parts.

Replace
components
as needed with
genuine Bendix®
parts.

FAIL

YES

Perform Guide Pin
Bearing Inspection
(Sec. 4.5 of
SD-23-7541).
– PASS/FAIL

NO

Reference
instructions in
Bendix Technical
Bulletin (TCH-023007), then proceed
to Guide Pin Bearing
Inspection.

Reference Instructions in Bendix
Technical Bulletin (TCH-023-007), then
proceed to Guide Pin Bearing Inspection.

PASS

Can both inboard
and outboard pads
be removed from the
caliper by hand?
– YES/NO

FAIL

Re-install a new or reworked actuator, apply and
release the brakes, and re-inspect running clearance
per (Sec. 4.1 of SD-23-7541).
– PASS/FAIL

FAIL (outside
0.6-1.2 mm tolerance)

PASS

Bendix technical documents
(such as SD-23-7541) can be
found at the online Document
Library at B2Bendix.com.

NO

Perform Guide Pin Bearing
Inspection (Sec. 4.5 of SD-23-7541).

FAIL

Air Disc Brake OK.

Confirm that the return spring
is not broken and the actuator
pushrod does not touch the
rubber seal.
Actuator pushrod should not
extend more than 12 mm
from the rubber seal.
– PASS/FAIL

PASS

PASS

Inspect all hoses,
caps, covers, and
the brake exterior
for damage or kinks
(check at full left and
right steering lock).
– PASS/FAIL

FAIL

Replace
components
as needed with
genuine Bendix®
parts.

PASS

Perform
Troubleshooting
Procedure
Flowchart (Sec. 3.0
of SD-23-7541).

FAIL

Replace
components
as needed with
genuine Bendix®
parts.

PASS

Proceed to pad
fitment inspection.

FAIL

Perform
Troubleshooting
Procedure
Flowchart (Sec. 3.0
of SD-23-7541).

FAIL

Replace both the caliper and actuator.

Check
the clearance at
both tappets
simultaneously
Figure 16 – Running Clearance Check

35500 Chester Road • Avon, OH 44011 • 1-800-AIR-BRAKE (1-800-247-2725) • bendix.com
BW7634 ©Bendix Commercial Vehicle Systems LLC, a member of Knorr-Bremse • 05/2024 • All Rights Reserved

Calipers with Parking Brake Chambers

Do BOTH pads AND rotors have bright red
dust and/or white residue? **Since it is
possible that the caliper may have been
replaced after a previous high level of heat
event on this rotor, the intent is to confirm that
both the caliper and the pads have experienced
a high level of heat event.** (This assumes
that the pads would have been replaced at the
same time the caliper was replaced due to a
prior high level of heat event). – YES/NO

RUNNING
CLEARANCE
QUICK
INSPECTION
CAUTION: FOLLOW ALL
SAFE MAINTENANCE
PRACTICES.

YES

Calipers with parking brake actuator

YES

When both ends of an axle, or multiple brakes on a
single vehicle are affected, a thorough brake system
diagnosis is needed, as other factors – such as brake
balance, overloaded vehicles, or extreme
use – are likely the source.

PASS

Inspect all hoses, caps, covers, and
the brake exterior for damage or kinks
(check at full left and right steering lock).
– PASS/FAIL

NO

Inspect for leaks in the parking system and broken
spring brake chambers.
– PASS/FAIL

FAIL

Repair leaks in the parking system
or replace the suspect spring brake
actuator per Bendix Service Data Sheet
(SD-23-7541).

Do any other brake rotors
OR pads on the vehicle
have bright red dust OR
white residue?
– YES/NO

PASS

Proceed to actuator/
caliper interface and
corrosion inspections.

FAIL

Replace components as
needed with genuine
Bendix® parts.

REDororWHITE
WHITE Pads
RED
Pads

PASS

On level ground, with the wheels
chocked and the parking brake
temporarily released, verify there
is sufficient running clearance
between the pads. Using hand
pressure only (no tools), check
for inboard/outboard movement
of the brake caliper. Small
movement of less than 0.08
in. (2 mm) – approximately the
thickness of a nickel – indicates
that there is sufficient running
clearance and the caliper
is sliding freely. For a more
accurate reading, a dial indicator
may be used to measure running
clearance. The recommended
running clearance range is
0.024-0.047 in. (0.6-1.2 mm).
Fail if the caliper movement or
running clearance are unable
to be confirmed. – PASS/FAIL

NO

RED
Rotor
REDororWHITE
WHITE Rotor

Remove the wheel and with the spring brakes
released or caged, push the caliper assembly
inboard on its guide pins. Note: To fully release
the spring brakes, ensure that the air system
pressure is at least 90 psi. Using a suitable tool
(for example a short pry bar), press the inboard
pad away from the tappets. Check that there is
no dirt, etc. in the gap, and clean if necessary.
Then use two long-blade feeler gauges to
measure – over the whole tappet surface – the
gap between them and the inboard pad
backplate. ( See Figure 16.) The gap should be
between 0.024 in. (0.6 mm) and 0.047 in.
(1.2 mm). PASS if the gap is within the given
range. – PASS/FAIL

PASS

PASS

Air Disc Brake OK.

FAIL

Replace components
as needed with
genuine Bendix®
parts.

Inspect all hoses, caps,
covers, and the brake exterior
for damage or kinks.
– PASS/FAIL

PASS (within
0.6-1.2 mm tolerance)
Can both inboard and
outboard pads be removed
from the caliper by hand?
– YES/NO

YES

NO

Perform Guide Pin Bearing Inspection
(Sec. 4.5 of SD-23-7541).

PASS

Air Disc Brake OK.

FAIL

Replace components as
needed with genuine
Bendix® parts.

Reference Instructions in Bendix Technical
Bulletin (TCH-023-007 ),then proceed to
Guide Pin Bearing Inspection.

Can both inboard and
outboard pads be
removed from the caliper
by hand?
– YES/NO

PASS

YES

Perform Guide Pin Bearing Inspection
(Sec. 4.5 of SD-23-7541).
– PASS/FAIL

NO

Reference instructions in Bendix
Technical Bulletin (TCH-023-007),
then proceed to Guide Pin Bearing
Inspection.

PASS

Perform
Troubleshooting
Procedure
Flowchart (Sec. 3.0
of SD-23-7541).

FAIL

Replace
components
as needed with
genuine Bendix®
parts.

Proceed to pad
fitment inspection.
FAIL

Pull
Caliper
Inboard

FAIL

Cage parking brake chamber
before removing. Remove the
actuator to inspect the caliper
and actuator internals for
corrosion. Confirm the caliper
lever applies and fully releases
smoothly by manually cycling
the lever with a screwdriver.
– PASS/FAIL

Figure 15 – Pull Caliper Inboard

Bendix technical documents
(such as SD-23-7541) can be
found at the online Document
Library at B2Bendix.com.
Check
the clearance at
both tappets
simultaneously
Figure 16 – Running Clearance Check

PASS

FAIL (outside
0.6-1.2 mm tolerance)

PASS

PASS

Confirm that the return spring
is not broken and the actuator
pushrod does not touch the
rubber seal.
Actuator pushrod should not
extend more than 12 mm
from the rubber seal.
– PASS/FAIL

PASS

FAIL

FAIL

Re-install a new or reworked actuator, apply and
release the brakes and re-inspect running clearance
per (Sec. 4.1 of SD-23-7541).
– PASS/FAIL

FAIL

FAIL

Replace both the caliper and actuator.

35500 Chester Road • Avon, OH 44011 • 1-800-AIR-BRAKE (1-800-247-2725) • bendix.com
BW7634 ©Bendix Commercial Vehicle Systems LLC, a member of Knorr-Bremse • 05/2024 • All Rights Reserved

FAIL

Perform
Troubleshooting
Procedure
Flowchart (Sec. 3.0
of SD-23-7541).