
BASE BRAKE SYSTEM
INDEX
page page
DESCRIPTION AND OPERATION
CHASSIS TUBES AND HOSES.............. 6
FRONT DISC BRAKES..................... 2
MASTER CYLINDER...................... 6
PARKING BRAKES........................ 4
PROPORTIONING VALVES................. 5
REAR DISC BRAKES...................... 4
REAR DRUM BRAKES..................... 4
REAR WHEEL HUB/BEARING............... 8
RED BRAKE WARNING LAMP............... 7
STOP LAMP SWITCH...................... 8
VACUUM BOOSTER...................... 6
DIAGNOSIS AND TESTING
BRAKE FLUID CONTAMINATION............ 19
BRAKE SYSTEM BASIC DIAGNOSIS GUIDE.... 9
BRAKE SYSTEM DIAGNOSIS CHARTS....... 10
DRUM BRAKE AUTOMATIC ADJUSTER....... 14
PROPORTIONING VALVES................ 16
RED BRAKE WARNING LAMP TEST......... 19
ROTOR THICKNESS AND RUNOUT.......... 14
STOP LAMP SWITCH TEST PROCEDURE..... 19
SERVICE PROCEDURES
BRAKE BLEEDING....................... 20
BRAKE DRUM MACHINING................ 23
BRAKE FLUID LEVEL CHECK.............. 19
BRAKE ROTOR MACHINING............... 22
BRAKE TUBE REPAIR.................... 25
MASTER CYLINDER BLEEDING............ 21
PARK BRAKE LEVER AUTO ADJUSTER
MECHANISM.......................... 23
REMOVAL AND INSTALLATION
CHASSIS TUBES AND HOSES.............. 47
FRONT DISC BRAKE CALIPER............. 26
FRONT DISC BRAKE SHOES.............. 28
MASTER CYLINDER..................... 41
PARK BRAKE CABLES.................... 50
PARK BRAKE LEVER ASSEMBLY........... 48PARK BRAKE LEVER OUTPUT CABLE....... 49
PARK BRAKE SHOES WITH REAR DISC
BRAKES............................. 55
PROPORTIONING VALVE (BASE BRAKES).... 47
REAR BRAKE DRUM..................... 34
REAR BRAKE SHOE SUPPORT PLATE....... 37
REAR BRAKE SHOES.................... 35
REAR BRAKE WHEEL CYLINDER........... 38
REAR DISC BRAKE CALIPER.............. 30
REAR DISC BRAKE SHOES................ 32
REAR HUB/BEARING..................... 39
STOP LAMP SWITCH..................... 57
VACUUM BOOSTER..................... 44
WHEEL AND TIRE ASSEMBLY.............. 26
DISASSEMBLY AND ASSEMBLY
BRAKE FLUID LEVEL SWITCH............. 58
BRAKE FLUID RESERVOIR................ 57
FRONT AND REAR DISC BRAKE CALIPER.... 58
WHEEL CYLINDER (REAR DRUM BRAKE).... 63
CLEANING AND INSPECTION
CHASSIS TUBES AND HOSES.............. 65
FRONT DISC BRAKES.................... 63
REAR DISC BRAKES..................... 64
REAR DRUM BRAKE WHEEL CYLINDER...... 65
REAR DRUM BRAKES.................... 64
REAR WHEEL HUB AND BEARING ASSEMBLY . 65
ADJUSTMENTS
PARK BRAKE ADJUSTMENT............... 66
REAR DRUM BRAKE SHOE ADJUSTMENT.... 65
STOP LAMP SWITCH..................... 65
SPECIFICATIONS
BRAKE ACTUATION SYSTEM.............. 67
BRAKE FASTENER TORQUE SPECIFICATIONS . 67
BRAKE FLUID.......................... 67
SPECIAL TOOLS
BASE BRAKE SYSTEM................... 68
DESCRIPTION AND OPERATION
FRONT DISC BRAKES
The front disc brakes (Fig. 1) and (Fig. 2) consists
of the following components:
²The driving hub
²Braking disc (rotor)
²Caliper assembly - single piston, floating type
²Brake shoes and linings
The double pin calipers are mounted directly to the
steering knuckles and use no adapter. The caliper ismounted to the steering knuckle using bushings,
sleeves and 2 guide pin bolts which thread directly
into bosses on the steering knuckle (Fig. 2) and (Fig.
3).
Two machined abutments on the steering knuckle
position the caliper. The guide pin bolts, sleeves and
bushings control the side to side movement of the
caliper. The piston seal is designed to pull the piston
back into the bore of the caliper when the brake
pedal is released. This maintains the proper brake
shoe to rotor clearance (Fig. 4).
5 - 2 BRAKESPL

(2) Remove hydraulic brake tube (Fig. 26) from
proportioning valve controlling the rear wheel of the
vehicle which has premature wheel skid.
(3) Remove proportioning valve from that outlet
port of the master cylinder.
CAUTION: Be sure the pressure test fitting being
installed into master cylinder, has the correct
thread sizes for installation into the master cylinder
and the installation of the proportioning valve.
(4) Install Pressure Test Fitting, Special Tool
6805-1 or 6805-2 (Fig. 27) into the outlet port of the
master cylinder, which the proportioning valve was
removed from.
(5) Install proportioning valve into pressure test
fitting installed in master cylinder outlet port (Fig.
27).
CAUTION: Be sure the pressure test fitting being
installed into proportioning valve, has the correct
thread sizes for installation into the proportioning
valve and installation of brake tube fitting.
(6) Install Pressure Test Fitting, Special Tool
6805-3 or 6805-4 (Fig. 27) into the outlet port of the
proportioning valve.
(7) Connect brake hydraulic tube onto the pressure
test fitting that was installed in proportioning valve
(Fig. 27).
(8) Install a Pressure Gauge, Special Tool
C-4007-A into each pressure test fitting (Fig. 28).
Bleed air out of hose from pressure test fitting to
pressure gauge, at pressure gauge to remove all
trapped air. hose.
(9) With the aid of a helper, apply pressure to the
brake pedal until reading on proportioning valve
inlet gauge, is at the pressure shown on the followingchart. Then check the pressure reading on the pro-
portioning valve outlet gauge. If proportioning valve
outlet pressure does not agree with value shown on
the following chart, when inlet pressure shown on
chart is obtained, replace the proportioning valve. If
proportioning valve is within pressure specifications
do not replace proportioning valve.
(10) Check rear wheel brake shoe linings for con-
tamination or for replacement brake shoes not meet-
ing OEM brake lining material specifications. These
conditions can also be a possible cause for a prema-
ture rear wheel skid.
(11) Install proportioning valve in master cylinder
and hand tighten until proportioning is fully
installed and O-ring seal is seated into master cylin-
der. Then torque proportioning valve to 40 N´m (30
ft. lbs.).
(12) Install brake tube on proportioning valve.
Torque tube nut to 17 N´m (145 in. lbs.) torque.
(13) Bleed the affected brake line. See Bleeding
Brake System in the Service Adjustments section of
the manual for proper bleeding procedure
PROPORTIONING VALVE TEST WITH ABS
BRAKES
If premature cycling of the rear brake ABS occurs
on hard brake application, it could be an indication
that a malfunction has occurred with one of the pro-
portioning valves.
One proportioning valve controls the right rear
brake, and the other proportioning valve controls the
left rear brake (Fig. 29). Therefore, a road test to
determine which rear brake slides first is essential.
Once the wheel which is skidding first is determined,
Fig. 27 Proportioning Valve Installation For
Pressure Testing
Fig. 28 Pressure Gauges Installed On Pressure Test
Fittings
PLBRAKES 5 - 17
DIAGNOSIS AND TESTING (Continued)

CAUTION: Use only MoparTbrake fluid or an
equivalent from a tightly sealed container. Brake
fluid must conform to DOT 3 specifications. Do not
use petroleum-based fluid because seal damage in
the brake system will result.
If necessary, add specified brake fluid bringing
level to theFULLmark on the side of the master
cylinder brake fluid reservoir (Fig. 34).
BRAKE BLEEDING
NOTE: For bleeding the ABS hydraulic system, see
Bleeding Teves Mark 20 Hydraulic System in the
Service Procedures Section of the ABS Brake Sec-
tion in this group of the service manual.
CAUTION: Before removing the master cylinder
cover, wipe it clean to prevent dirt and other foreign
matter from dropping into the master cylinder.
PRESSURE BLEEDING
CAUTION: Use bleeder tank Special Tool C-3496-B
with required adapter for the master cylinder reser-
voir to pressurize the hydraulic system for bleed-
ing.
NOTE: Follow pressure bleeder manufacturer's
instructions for use of pressure bleeding equip-
ment.
When bleeding the brake system, some air may be
trapped in the brake lines or valves far upstream, as
much as ten feet from the bleeder screw (Fig. 35).
Therefore, it is essential to have a fast flow of a large
volume of brake fluid when bleeding the brakes to
ensure all the air gets out.The following wheel sequence for bleeding the
brake hydraulic system should be used to ensure
adequate removal of all trapped air from the hydrau-
lic system.
²Left rear wheel
²Right front wheel
²Right rear wheel
²Left front wheel
(1) Attach a clear plastic hose to the bleeder screw
starting at the right rear wheel and feed the hose
into a clear jar containing enough fresh brake fluid
to submerge the end of the hose (Fig. 36).
(2) Open the bleeder screw at leastone full turn
or more to obtain an steady stream of brake fluid
(Fig. 37).
(3) After 4 to 8 ounces of fluid has been bled
through the brake and an air-free flow is maintained
in the clear plastic hose and jar, close the bleeder
screw.
(4) Repeat the procedure at all the other remain-
ing bleeder screws. Then check the pedal for travel.
If pedal travel is excessive or has not been improved,
Fig. 34 Master Cylinder Fluid Level
Fig. 35 Trapped Air in Brake Line
Fig. 36 Proper Method for Purging Air From Brake
System (Typical)
5 - 20 BRAKESPL
SERVICE PROCEDURES (Continued)

enough fluid has not passed through the system to
expel all the trapped air. Be sure to monitor the fluid
level in the pressure bleeder. It must stay at the
proper level so air will not be allowed to reenter the
brake system through the master cylinder reservoir.
BLEEDING WITHOUT A PRESSURE BLEEDER
NOTE: Correct bleeding of the brakes hydraulic
system without the use of pressure bleeding equip-
ment will require the aid of a helper.
The following wheel sequence for bleeding the
brake hydraulic system should be used to ensure
adequate removal of all trapped air from the hydrau-
lic system.
²Left rear wheel
²Right front wheel
²Right rear wheel
²Left front wheel
(1) Attach a clear plastic hose to the bleeder screw
starting at the right rear wheel and feed the hose
into a clear jar containing enough fresh brake fluid
to submerge the end of the hose (Fig. 36).
(2) Pump the brake pedal three or four times and
hold it down before the bleeder screw is opened.
(3) Open the bleeder screw at least 1 full turn.
When the bleeder screw opens the brake pedal will
drop.
(4) Close the bleeder screw. Release the brake
pedal onlyafterthe bleeder screw is closed.
(5) Repeat steps 1 through 3, four or five times at
each bleeder screw. Then check the pedal for travel.
If pedal travel is excessive or has not been improved,
enough fluid has not passed through the system to
expel all the trapped air. Be sure to monitor the fluid
level in the master cylinder reservoir. It must stay at
the proper level so air will not be allowed to re-enter
the brake system.(6) Test drive vehicle to be sure brakes are operat-
ing correctly and that pedal is solid.
MASTER CYLINDER BLEEDING
(1) Clamp the master cylinder in a vise. Attach
Bleeding Tubes, Special Tool 6802 to the master cyl-
inder (Fig. 38) and (Fig. 39). Position so outlets of
Bleeding Tubes will be below surface of brake fluid
when reservoir is filled to its proper level.
(2) Fill brake fluid reservoir with brake fluid con-
forming to DOT 3 specifications such as Mopar or an
Equivalent.
(3) Using a wooden dowel per (Fig. 40). Depress
push rod slowly, and then allow pistons to return to
released position. Repeat several times until all air
bubbles are expelled.
(4) Remove bleeding tubes from master cylinder
outlet ports, plug outlet ports and install fill cap on
reservoir.
Fig. 37 Open Bleeder Screw at Least One Full Turn
Fig. 38 Bleeding Tubes Attached to ABS Master
Cylinder
Fig. 39 Bleeding Tubes Attached To Non-ABS
Master Cylinder
PLBRAKES 5 - 21
SERVICE PROCEDURES (Continued)

carefullyinserting a small screw driver between the
push rod of the power brake vacuum booster and vac-
uum seal (Fig. 107) and pry seal out of power brake
vacuum booster.Do not attempt to pry seal out of
master cylinder by inserting a tool between
seal and power brake vacuum booster.
BLEEDING MASTER CYLINDER
(1) Clamp the master cylinder in a vise. Attach
Bleeding Tubes, Special Tool 6802 to the master cyl-
inder (Fig. 108) and (Fig. 109). Position tubes so out-
lets of Bleeding Tubes will be below surface of brake
fluid when reservoir is filled to proper level.
(2) Fill brake fluid reservoir with brake fluid con-
forming to DOT 3 specifications such as Mopar or an
Equivalent.
(3) Using a wooden dowel per (Fig. 110), depress
push rod slowly and then allow pistons to return to
released position. Repeat several times until all air
bubbles are expelled.
Fig. 106 Master Cylinder Mounting To Vacuum
Booster
Fig. 107 Removing Seal From Vacuum Booster
Fig. 108 Bleeding Tubes Attached to ABS Master
Cylinder
Fig. 109 Bleeding Tubes Attached To Non-ABS
Master Cylinder
Fig. 110 Bleeding Master Cylinder
5 - 42 BRAKESPL
REMOVAL AND INSTALLATION (Continued)

MUST always be used when installing brake
hose to caliper.
(12) Bleed the brake system (see Bleeding Brake
System).
WHEEL CYLINDER (REAR DRUM BRAKE)
DISASSEMBLE
To disassemble the wheel cylinders, proceed as fol-
lows:
(1) Pry boots away from cylinders and remove (Fig.
183).
(2) PressINon one piston to force out opposite
piston, cup and spring (Fig. 183). Then using a soft
tool such as a dowel rod, press out the cup and piston
that remain in the wheel cylinder.
(3) Wash wheel cylinder, pistons, and spring (Fig.
183) in clean brake fluid or alcohol;(DO NOT USE
ANY PETROLEUM BASE SOLVENTS)clean thor-
oughly and blow dry with compressed air. Inspect cyl-
inder bore and piston for scoring and pitting. (Do not
use a rag as lint from the rag will stick to bore sur-
faces.)
(4) Wheel cylinder bores and pistons that are
badly scored or pitted should be replaced. Cylinder
walls that have light scratches, or show signs of cor-
rosion, can usually be cleaned with crocus cloth,
using a circular motion. Black stains on the cylinder
walls are caused by piston cups and will not impair
operation of cylinder.
ASSEMBLE
Before assembling the pistons and new cups in the
wheel cylinders, dip them in clean brake fluid. If theboots are deteriorated, cracked or do not fit tightly on
the pistons or the cylinder casting, install new boots.
(1) Coat cylinder bore with clean brake fluid.
(2) Lightly coat the sealing lip and outer surfaces
of the wheel cylinder cups with Mopar Protect-A-Cup
Lubricant.
(3) Install expansion spring with cup expanders in
cylinder. Install cups in each end of cylinder with
open end of cups facing each other (Fig. 183).
(4) Install piston in each end of cylinder having
the flat face of each piston contacting the flat face of
each cup, already installed (Fig. 183).
(5) Coat the interior surfaces of the push on boots
(Fig. 183) with the Mopar Protect-A-Cup Lubricant
(6) Install a boot over each end of cylinder (Fig.
183).Be careful not to damage boot during
installation.
CLEANING AND INSPECTION
FRONT DISC BRAKES
BRAKE PAD LINING WEAR
If a visual inspection does not adequately deter-
mine the condition of the lining, a physical check will
be necessary. To check the amount of lining wear,
remove the wheel and tire assemblies, and the cali-
pers.
Remove the front disc brake shoes. Refer to Front
Disc Brake Shoe Removal in the Removal And Instal-
lation section in this group of the service manual for
the required procedure.
The combined brake shoe and lining material
thickness should be measured at the thinnest part of
the assembly.
When a set of brake shoes are worn to a total
thickness of approximately 7.95 mm (5/16 inch) they
should be replaced.
Replacebothbrake shoe assemblies (inboard and
outboard). It is necessary thatbothfront wheel sets
be replaced whenever brake shoe assemblies on
either side are replaced.
If the brake shoe assemblies do not require
replacement, reinstall, the assemblies making sure
each brake shoe is returned to the original position.
Refer to Front Disc Brake Shoe Installation in the
Removal And Installation section in this group of the
service manual for the required procedure.
CALIPER INSPECTION
Check for brake fluid leaks in and around boot
area and inboard lining, and for any ruptures, brit-
tleness or damage to the piston dust boot. If the boot
Fig. 182 Installing Dust Boot In Caliper Counterbore
PLBRAKES 5 - 63
DISASSEMBLY AND ASSEMBLY (Continued)

For the specific procedure covering the inspection
of the brake fluid level and adding brake fluid to the
reservoir, refer to the Service Adjustments Section in
this group of the service manual.
BLEEDING TEVES MARK 20 HYDRAULIC SYSTEM
The hydraulic system for the base brakes must be
bled anytime air enters the hydraulic system. Air can
enter the hydraulic system for the base brakes due to
the disconnection of brake lines, hoses or any other
hydraulically operated component of the base brake
system. The ABS system, particularly the ICU,
should only be bled when the ICU is replaced or it is
removed from the vehicle. The ICU must also always
be bled if for any reason it is suspected that the ICU
has ingested air. Under most circumstances that
require the bleeding of the brakes hydraulic system,
only the base brake hydraulic system needs to be
bled.
It is important to note that excessive air in the
brake system will cause a soft or spongy feeling
brake pedal.
During the brake bleeding procedure, be sure the
brake fluid level remains close to the FULL level in
the master cylinder fluid reservoir. Check the fluid
level periodically during the bleeding procedure and
add DOT 3 brake fluid as required.
The ITT Teves Mark 20 ABS must be bled as two
independent braking systems. The non ABS portion
of the brake system is to be bled the same as any
non ABS system. Refer to the Service Adjustments
section in this manual for the proper bleeding proce-
dure to be used. This brake system can be either
pressure bled or manually bled.
The ABS portion of the brake system MUST be
bled separately. This bleeding procedure requires the
use of the DRB Diagnostic Tester and the bleeding
sequence procedure outlined below.
ABS BLEEDING PROCEDURE
When bleeding the ABS system, the following
bleeding sequenceMUSTbe followed to insure com-
plete and adequate bleeding. The ABS system can be
bled using a manual bleeding procedure or standard
pressure bleeding equipment.
If the brake system is to be bled using pressurized
bleeding equipment, refer to Bleeding Brake System
in the Service Adjustments section at the beginning
of this group for proper equipment usage and proce-
dures.
(1) Assemble and install all brake system compo-
nents on the vehicle making sure all hydraulic fluid
lines are installed and properly torqued.
(2) Connect the DRB Diagnostics Tester to the
diagnostics connector. The Teves Mark 20 ABS diag-
nostic connector is located under the instrument
panel to the left of the steering column cover.(3) Using the DRB, check to make sure the CAB
does not have any fault codes stored. If it does,
remove them using the DRB.
WARNING: WHEN BLEEDING THE BRAKE SYS-
TEM WEAR SAFETY GLASSES. A CLEAR BLEED
TUBE MUST BE ATTACHED TO THE BLEEDER
SCREWS AND SUBMERGED IN A CLEAR CON-
TAINER FILLED PART WAY WITH CLEAN BRAKE
FLUID. DIRECT THE FLOW OF BRAKE FLUID AWAY
FROM THE PAINTED SURFACES OF THE VEHICLE.
BRAKE FLUID AT HIGH PRESSURE MAY COME
OUT OF THE BLEEDER SCREWS WHEN OPENED.
(4) Bleed the base brake system using the stan-
dard pressure or manual bleeding procedure as out-
lined in the Service Adjustments section of this
service manual.
(5) Using the DRB, go to the9Bleed ABS9routine.
Apply the brake pedal firmly and initiate the9Bleed
ABS9cycle one time. Release the brake pedal.
(6) Bleed the base brake system again, as in step
Step 4 above.
(7) Repeat steps Step 5 and Step 6 above until
brake fluid flows clear and is free of any air bubbles.
Check brake fluid level in reservoir periodically to
prevent reservoir from running low on brake fluid.
(8) Test drive the vehicle to be sure brakes are
operating correctly and that the brake pedal does not
feel spongy.
REMOVAL AND INSTALLATION
ABS GENERAL SERVICE PRECAUTIONS
CAUTION: Review this entire section prior to per-
forming any mechanical work on a vehicle equipped
with the ITT Tevis Mark 20 ABS brake system. This
section contains information on precautions per-
taining to potential component damage, vehicle
damage and personal injury which could result
when servicing an ABS equipped vehicle.
CAUTION: Only the recommended jacking or hoist-
ing positions for this vehicle are to be used when-
ever it is necessary to lift a vehicle. Failure to raise
a vehicle from the recommended locations could
result in lifting a vehicle by the hydraulic control
unit mounting bracket. Lifting a vehicle by the
hydraulic control unit mounting bracket will result
in damage to the mounting bracket and the hydrau-
lic control unit.
PLBRAKES 5 - 81
SERVICE PROCEDURES (Continued)