1993 CHEVROLET DYNASTY abs

of brake fluid is not maintained before brake pedal
bottoms, close bleed screw and repeat steps 8 and 9
until an air free flow is maintained.(11) After an air-free flow of brake fluid is main-
tained from the primary accumulator bleed screw, close
and lightly tighten bleed screw. Then release pressure
from brake pedal. Do not release force from brake
pedal prior to closing and tightening bleed
screw. Note: For the next modulator assembly bleed-
ing procedure, use of the DRB is not required.
This step of the bleed procedure does not require
modulator solenoids to be operated for bleeding
to be performed. (12) Pump brake pedal several times, then apply
and hold a constant medium to heavy force on the
brake pedal. (13) Again without firing modulator solenoids, open
primary accumulator circuit bleed screw (Fig. 4) 1 full
turn. This will ensure an adequate flow of brake fluid
from the primary accumulator circuit. (14) Bleed primary accumulator circuit until a clear,
air-free flow of brake fluid is maintained from the
accumulator bleed screw or the brake pedal bottoms. If
an air-free flow of brake fluid is not maintained from
the bleed screw before the brake pedal bottoms. First,
close bleed screw and then repeat steps 11 and 12 of
this bleeding procedure until an air-free flow is main-
tained. (15) After an air-free flow of brake fluid is main-
tained from the primary accumulator circuit bleed
screw, close and lightly tighten bleed screw. Then re- lease force from brake pedal.
Do not release force
from brake pedal prior to closing and tightening
bleeder screw. (16) After primary accumulator bleed screw is
closed, remove bleed hose from bleed screw. (17) Torque secondary accumulator bleed screw to 9
N Im (80 in. lbs.).
5 MODULATOR ASSEMBLY SECONDARY SUMP CIRCUIT (1) Transfer clear bleed tube to secondary sump
bleed screw on modulator assembly (Fig. 5). Then
install bleed tube into a container partially filled with
fresh clean brake fluid (Fig. 5).
(2) Pump brake pedal several times, then apply and
hold a constant medium to heavy force on brake pedal. (3) Open the secondary sump circuit bleed screw
(Fig. 5) at least 1 full turn. This will ensure an
adequate flow of brake fluid is expelled from the
secondary sump circuit. (4) Using the DRB, select the bleed ABS hydraulic
unit mode. Then select the secondary circuit valves.
(The LF and RR solenoids will alternately fire for five
seconds). Continue bleeding secondary sump circuit
until an air-free flow of brake fluid from secondary
sump bleed screw is maintained or brake pedal bot-
toms. If an air-free flow of brake fluid is not maintained
before brake pedal bottoms, close bleed screw and
repeat steps 2 through 4 until an air-free flow is
maintained. (5) After an air-free flow of brake fluid is maintained
from secondary sump bleed screw, close and lightly
tighten bleed screw. Then release force from
Fig. 4 Bleeding Modulator Assembly Primary Accu- mulator Circuit
Fig. 5 Bleeding Modulator Assembly SecondarySump Circuit
5 - 28 ANTILOCK 4 BRAKE SYSTEM Ä

brake pedal. Do not release brake pedal prior to
closing and tightening bleeder screw. (6) After secondary sump bleed screw is closed, re-
move bleed hose from bleed screw. (7) Torque secondary sump bleed screw to 9 N Im (80
in. lbs.).
6 MODULATOR ASSEMBLY SECONDARY ACCUMULATOR
CIRCUIT
(8) Transfer bleed tube to secondary accumulator
bleed screw (Fig. 6). Then install bleed tube into a
container partially filled with fresh clean brake fluid
(Fig. 6).
(9) Apply constant, medium to heavy force on brake
pedal. Then using the DRB, select the bleed ABS
hydraulic unit mode, and then select the secondary
circuit valves. (The LF and RR modulator assembly
solenoids will fire for 5 seconds). (10) Open the secondary accumulator circuit bleed
screw (Fig. 6) at least one full turn. This will ensure an
adequate flow of brake fluid is expelled from the
secondary accumulator circuit. Continue to bleed pri- mary accumulator circuit, until an air-free flow of
brake fluid from the bleed screw is maintained or brake
pedal bottoms. If an air-free flow of brake fluid is not
maintained from bleed screw before brake pedal bot-
toms, close bleed screw and then repeat steps 8 and 9
until an air free flow is maintained. (11) After an air-free flow of brake fluid is main-
tained from the bleed screw, close and lightly tighten
the bleed screw. Then release force from brake pedal.
Do not release force from brake pedal prior to
closing and tightening bleeder screw. Note: For the next modulator assembly bleed-
ing procedure, use of the DRB is not required.
This step of the bleeding procedure does not
require the modulator solenoids to be operated
for bleeding to be performed. (12) Pump brake pedal several times, then apply
and hold constant medium to heavy force on brake
pedal. (13) Again without firing modulator assembly sole-
noids, open secondary accumulator circuit bleed screw
(Fig. 6) at least 1 full turn. This will ensure an
adequate flow of brake fluid is expelled from the
secondary accumulator circuit. (14) Bleed secondary accumulator circuit until a
clear, air-free flow of brake fluid is maintained from the
secondary accumulator bleed screw or the brake pedal
bottoms. If an air- free flow of brake fluid is not
maintained from secondary accumulator bleed screw
before brake pedal bottoms, repeat steps 12 and 13 of
this bleeding procedure until an air-free flow is main-
tained. (15) After an air free flow of brake fluid is main-
tained from secondary accumulator circuit bleed screw,
close and lightly tighten bleed screw. Then release
force from brake pedal. Do not release force from
brake pedal prior to closing and tightening bleed
screw. (16) After secondary accumulator bleed screw is
closed, remove bleed hose from bleed screw. (17) Torque secondary accumulator bleed screw to 9
N Im (80 in. lbs.).
PUMP/MOTOR SERVICE
On the Bendix Antilock 4 Brake System the
Pump/Motor assembly can only be serviced as part of
Modulator Assembly.
Fig. 6 Bleeding Modulator Assembly Secondary Ac- cumulator Circuit
Ä ANTILOCK 4 BRAKE SYSTEM 5 - 29

(7) Remove battery acid shield, (Fig. 6) from the ABS
modulator assembly.
(8) Remove the 6 tube nuts (Fig. 7), attaching hy-
draulic brake line tube bundle to modulator assembly,
thread savers and proportioning valves. Then remove
the hydraulic brake lines as an assembly, from the
modulator assembly. Brake lines do not need to be
loosened at junction block.
(9) Raise vehicle.
(10) Remove the vehicle's wiring harness 10 way
connector, from the modulator assembly (Fig. 8). (11) Remove 2 bolts (Fig. 9) attaching bottom of
modulator assembly to its mounting bracket. (12) Lower vehicle.
(13) Remove bolt (Fig. 10) attaching front of modu-
lator assembly to mounting bracket. (14) Remove modulator assembly from mounting
bracket and remove from vehicle.
Fig. 8 Vehicle Wiring Harness Connection To Modulator Assembly
Fig. 9 Modulator Assembly To Mounting Bracket Attaching Bolts
Fig. 10 Front Modulator Assembly To Bracket Bolt
Fig. 6 ABS Modulator Assembly Acid Shield
Fig. 7 Hydraulic Brake Line Connections To Modula- tor Assembly
Ä ANTILOCK 4 BRAKE SYSTEM 5 - 31

(4) If equipped, remove the 2 bolts (Fig. 4) attaching
speed control vacuum reservoir to battery tray. Then
remove vacuum reservoir (Fig. 4) from the battery tray.
Vacuum lines (Fig. 4) do not need to be removed
from vacuum reservoir. (5) Remove the 4 bolts attaching battery tray (Fig.
5) to frame rail and fender shield of the vehicle.
Then remove battery tray.
(6) Remove battery acid shield, (Fig. 6) from the
ABS modulator assembly.
(7) Remove the 6 tube nuts (Fig. 7), attaching hy-
draulic brake line tube bundle to modulator assem-
bly, thread savers and proportioning valves. Then
remove the 6 hydraulic brake lines as an assembly,
from the modulator assembly. (8) Remove electrical connector from the brake
pressure differential warning switch on hydraulic
junction block (Fig. 8). (9) Remove the primary and secondary hydraulic
brake tubes (Fig. 9) going from the master cylinder
to the junction block, from both master cylinder and
junction block. (10) Remove the brake hydraulic tube going to the
vehicle's left front wheel from the junction block. (11) Remove the 6 hydraulic brake tubes at the hy-
draulic junction block, coming from the antilock mod-
ulator assembly.
Fig. 5 Battery Tray And Attaching Bolts
Fig. 6 ABS Modulator Assembly Acid Shield
Fig. 2 Battery Heat Shield And Hold Down Clamp
Fig. 3 Battery Tray Shield
Fig. 4 Speed Control System Vacuum Reservoir
Ä ANTILOCK 4 BRAKE SYSTEM 5 - 35

Antilock 4 Brake System in this service manual
supplement for required bleeding procedure.(9) Install battery acid shield (Fig. 14) onto the ABS
modulator assembly. Be sure acid shield is securely
attached to modulator assembly before installing
battery tray. (10) Install battery tray into vehicle. Then install
the 4 bolts (Fig. 15) attaching battery tray to inner
fender and frame rail. Torque the 4 battery tray attach-
ing bolts to 20 N Im (175 in.lbs.).
(11) If equipped, install speed control vacuum reser-
voir on battery tray. Install the 2 speed control vacuum
reservoir attaching bolts (Fig. 16). Torque the 2
vacuum reservoir attaching bolts to 4 N Im (30 in. lbs.).
(12) Install battery tray access cover (Fig. 17) on
bottom of battery tray. The access cover MUST be
on battery tray, before battery is installed. (13) Install battery on battery tray. Then install
and securely tighten the battery hold down clamp
(Fig. 18). Then install battery heat shield, on battery
(Fig. 18). (14) Install battery cables on battery. Securely
tighten clamping bolts on battery cable terminals. (15) Reset any electrical components of the vehicle
which were affected by the removal of the battery. (16) Road test vehicle to verify correct operation of
the vehicles's base and Antilock brake systems.
Fig. 13 Battery Connected To Vehicle For Bleeding Modulator Assembly
Fig. 14 Modulator Assembly Acid Shield Installed
Fig. 11 Hydraulic Brake Line Connections atModulator Assembly
Fig. 12 Torquing Brake Line Connections To Modulator Assembly
Ä ANTILOCK 4 BRAKE SYSTEM 5 - 37

MASTER CYLINDER AND POWER BOOSTER
REMOVAL AND INSTALLATION If the Master Cylinder or Power Booster need to be
removed for replacement or servicing of other vehicle
components. Refer to Master Cylinder or Power
Brake Service section in group 5 of the 1993 M.Y.
Front Wheel Drive Car service manual. After servicing master cylinder, refer back to this
service manual supplement for the appropriate proce-
dure and sequence used to bleed the base and Anti-
lock portion of the brake system.
PROPORTIONING VALVES (FIG. 1)
CAUTION: Proportioning valves should never be
disassembled.
REMOVAL (1) Disconnect and remove both battery cables
from battery. (2) Remove heat shield (Fig. 2) from the battery.
Then remove battery hold down clamp (Fig. 2) and
battery from battery tray.
Fig. 15 Battery Tray Installation And Attaching Bolts
Fig. 16 Vacuum Reservoir Installation And Attaching Bolts
Fig. 17 Battery Tray Access Shield Installed
Fig. 18 Battery Hold Down Clamp And Heat Shield Installed
Fig. 1 ABS Proportioning Valve Identification
5 - 38 ANTILOCK 4 BRAKE SYSTEM Ä

(3) Remove battery tray access cover (Fig. 3) from
battery tray. Do not discard, access cover MUST be
put back on battery tray, when battery is rein-
stalled.
(4) If equipped, remove the 2 bolts (Fig. 4) attaching
speed control vacuum reservoir to battery tray. Then
remove speed control vacuum reservoir (Fig. 4) from
the battery tray. Vacuum lines (Fig. 4) do not need
to be removed from vacuum reservoir. (5) Remove the 4 bolts attaching battery tray (Fig. 5)
to frame rail and fender shield of vehicle. Then remove
battery tray from vehicle. (6) Remove battery acid shield, (Fig. 6) from the ABS
modulator assembly. (7) Remove brake tube from the proportioning valve,
requiring removal from modulator assembly (Fig. 7). (8) Remove proportioning valve (Fig. 7) requiring
replacement from the modulator assembly. INSTALL
(1) Slightly moisten proportioning valve to modulator
assembly sealing O-Ring with fresh clean brake fluid.
(2) Install proportioning valve into modulator as-
sembly by hand, until O-Ring seal is fully seated
Fig. 4 Speed Control System Vacuum Reservoir
Fig. 5 Battery Tray And Attaching Bolts
Fig. 6 ABS Modulator Assembly Acid Shield
Fig. 2 Battery Heat Shield And Hold Down Clamp
Fig. 3 Battery Tray Shield
Ä ANTILOCK 4 BRAKE SYSTEM 5 - 39

against modulator assembly. Then torque proportion-
ing valve to 35 N Im (26 ft. lbs.) torque.
(3) Install hydraulic brake line on proportioning
valve and hand start tube nut into proportioning valve.
Torque tube nut to 18 N Im (159 in. lbs.) torque.
(4) Using approved battery jumper cables, attach
battery, to the vehicles negative and positive battery
cables (Fig. 8). (5) Bleed the vehicles base brake and Antilock brake
hydraulic systems. Refer to Bleeding Bendix Antilock 4
Brake System in this service manual supplement for
required bleeding procedure. (6) Install battery acid shield (Fig. 9) onto the ABS
modulator assembly. Be sure acid shield is securely
attached to modulator assembly before installing
battery tray.
(7) Install battery tray in vehicle. Then install the 4
bolts (Fig. 10) attaching battery tray to inner fender
and frame rail. Torque the 4 battery tray attaching
bolts to 20 N Im (175 in.lbs.).
(8) If equipped, install speed control vacuum reser-
voir on battery tray. Install the 2 speed control vacuum
reservoir attaching bolts (Fig. 11). Torque the 2
vacuum reservoir attaching bolts to 4 N Im (30 in. lbs.).
(9) Install battery tray access cover (Fig. 12) on
bottom of battery tray. The access cover MUST be
on battery tray, before battery is installed in
battery tray.
Fig. 8 Battery Connected To Vehicle For Bleeding Modulator Assembly
Fig. 7 Proportioning Valve Removal From Modulator Assembly
Fig. 9 Modulator Assembly Acid Shield Installed
Fig. 10 Battery Tray Installation And Attaching Bolts
5 - 40 ANTILOCK 4 BRAKE SYSTEM Ä