LATCHING VERSUS NON-LATCHING ABS
FAULTS
Some faults detected by the CAB are latching; the
fault is latched and ABS is disabled until the igni-
tion switch is reset. Thus ABS is disabled even if the
original fault has disappeared. Other faults are non-
latching; any warning lights that are turned on, are
only turned on as long as the fault condition exists.
As soon as the condition goes away, the Antilock
Warning Light is turned off. Although a fault code
will be set in most cases.
BENDIX ANTILOCK 4 BRAKE SYSTEM
DIAGNOSTICS
Bendix Antilock 4 Brake System Diagnostics, be-
yond basic mechanical diagnostics, covered earlier in
this section, are accomplished by using the DRB scan
tool. See testing procedures outlined in the 1994 Ben-
dix Antilock 4 Diagnostics Manual.
Please refer to the above mentioned manual for
any further electronic diagnostics and service proce-
dures that are required on the Bendix Antilock 4
Brake System.
ON-CAR ABS BRAKE SYSTEM SERVICE
GENERAL SERVICE PRECAUTIONS
The following are general cautions which should be
observed when servicing the Bendix Antilock 4
Brake System and other vehicle electronic systems.
Failure to observe these precautions may result in
Antilock Brake System component damage.
If welding work is to be performed on a vehicle us-
ing an electric arc welder, disconnect the 60 way wir-
ing harness connector from the CAB, prior to
performing the welding operation.
The wiring harness connector should never be con-
nected or disconnected from the CAB with the igni-
tion key in the ON or Run position.
(3) Most components making up the assemblies of
the Bendix Antilock 4 Brake System can not be ser-
viced separately from those assemblies. This will re-
quire replacement of the complete assembly for the
servicing of these components. Do not disassemble
any component from an assembly which is desig-
nated as non-serviceable.
CHECKING BRAKE FLUID LEVEL
CAUTION: Only use brake fluid conforming to DOT
3 specifications, such as Mopar or Equivalent. Do
not use any fluid which contains a petroleum base.
Do not use a container which has been used for pe-
troleum based fluids or a container which is wet
with water. Petroleum based fluids will cause swell-
ing and distortion of rubber parts in the hydraulic
brake system. Water will mix with brake fluid, low-
ering the boiling point of the brake fluid, possibly
causing brake fluid to boil resulting in brake fade.
Keep all brake fluid containers capped to prevent
contamination. Remove the front cap of the master
cylinder reservoir and fill to the bottom of the split
ring.
For the specific procedure for the inspection of
brake fluid level and adding of brake to the reser-
voir. Refer to the Service Adjustments Section in this
group of the service manual.
BLEEDING BENDIX ANTILOCK 4 BRAKE SYSTEM
The base brakes and Antilock Brake System must
be bled anytime air is permitted to enter the hydrau-
lic system, due to disconnection of brake lines, hoses
or components.
If the Antilock Modulator Assembly is removed
from the vehicle, both the Base Brake System and
the Antilock Brake System must be bled using the
appropriate procedure. It is important to note that
excessive air in the brake system will cause a soft or
spongy feeling brake pedal.
During brake bleeding operations, ensure that
brake fluid level remains close to the FULL level in
the reservoir. Check brake fluid level periodically
during bleeding procedure, adding DOT 3 brake fluid
as required.
CAUTION: The base brake and Antilock brake hy-
draulic systems, on the Bendix Antilock 4 Brake
System, can NOT be bled using any type of brake
pressure bleeding equipment. This type of bleeding
equipment does not develop the pressure required
in the brake hydraulic system, to adequately bleed
all trapped air. The only approved method for bleed-
ing air out of the hydraulic system on vehicles
equipped with the Bendix Antilock 4 Brake System,
is the manual procedure of pressurizing the hydrau-
lic system using constant, moderate to heavy foot
pressure on the brake pedal.
The Bendix Antilock 4 Brake System must be bled
as two independent brake systems. The non ABS por-
tion of the brake system is to be bled the same as
any non ABS system. Refer to the Service Adjust-
ments section in this manual for the proper bleeding
procedure to be used. The Bendix Antilock 4 Brake
System can only be bled using a manual method of
pressurizing the brakes hydraulic system.
The Antilock portion of brake system MUST be
bled separately. This bleeding procedure requires the
use of the DRB Diagnostic tester and the bleeding se-
quence procedure outlined below.
Ä
ANTILOCK 4 BRAKE SYSTEM
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