AC system FORD MUSTANG 2003 Workshop Manual

DESCRIPTION AND OPERATION
Brake System
Component Locations
SECTION 206-
00: Brake System — General Information 2003 Mustang Workshop Manual Item Part
Number Description
1 2C346 Four wheel anti-
lock brake system (4WABS) Klj . 1 ba
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The vehicle is equipped with a vacuum-
assisted or a hydro-boost power braking system. Refer to
Section 206 - 07 .
The braking system is a front- to-rear split hydraulic system. Refer to Section 206 - 06 .
The front wheel brakes utilize a dual piston brake caliper and disc brake system. Refer to Section 206 -
03 .
The rear brakes utilize a single piston brake caliper and disc brake system. Refer to Section 206 - 04 .
The parking brake system is a mechanical system that is controlled by an independent hand- operated
parking brake control and is self- adjusting. Refer to Section 206 - 05 .
A 4- wheel anti- lock brake system or anti-lock brake system with traction control (4WABS) is optional
equipment on all models except Cobra. Cobra has ABS and traction control as standard equipment.
Refer to Section 206 - 09A . hydraulic control unit and control module assy (non-
traction)
1 2C353 Four wheel anti-
lock brake system (4WABS)
hydraulic control unit and control module assy
(traction) 2 2B559 Hydro-Boost brake booster and brake master
cylinder assy 3 2B195 Vacuum brake booster and brake master cylinder
assy
4 2K327 Rear disc brake assy
5 2780 Parking brake control
6 2B119 Front disc brake assy Klj . 2 ba
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DIAGNOSIS AND TESTING
Brake System
Refer to Wiring Diagrams Cell
60 , Instrument Cluster for schematic and connector information.
Refer to Wiring Diagrams Cell 97 , Daytime Running Lamps for schematic and connector information.
Inspection and Verification WARNING: Use of any other than the approved DOT 3 brake fluid will cause permanent
damage to brake components and will render the brakes inoperative.
WARNING: Brake fluid contains polyglycol ethers and polyglycols. Avoid contact with
eyes. Wash hands thoroughly after handling. If brake fluid contacts eyes, flush eyes with
running water for 15 minutes. Get medical attention if irritation persists. If taken internally,
drink water and induce vomiting. Get medical attention immediately.
CAUTION: Do not spill brake fluid onto painted surfaces. If spilled, wipe up immediately.
NOTE: Always check the fluid level in the brake master cylinder reservoir (2K478) before performing
the test procedures. If the fluid level is not at the correct level, add High Performance DOT 3 Brake
Fluid C6AZ- 19542-AB or equivalent DOT 3 fluid meeting Ford specification ESA- M6C25-A.
NOTE: Prior to performing any diagnosis, make sure the brake warning indicator is functional. For
additional information, refer to Section 413 - 01 .
The first indication that something may be wrong in the brake system is a change in the feeling through
the brake pedal (2455). The brake warning indicator in the instrument cluster and the brake fluid level SECTION 206-
00: Brake System — General Information 2003 Mustang Workshop Manual Special Tool(s)
73 Digital Multimeter
105-
R0051 or Equivalent ABS Brake and Pressure Test
Kit
107-
02350 or Equivalent Tire and Wheel Runout Gauge
Set
134-
00199 or Equivalent Klj . 1 ba
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in the brake master cylinder reservoir are also indicators of system concerns.
If a wheel is locked and the vehicle must be moved, open a bleeder screw at the locked wheel (1007)
to let out enough fluid to relieve the pressure. Close the bleeder screw. This bleeding operation may
release the brakes but will not correct the cause of trouble. If this does not relieve the locked wheel
condition, repair the locked components before proceeding.
Inspect all hoses and connections. All unused vacuum connectors should be capped. Make sure
hoses and their connections are correctly secured and in good condition with no holes, soft or
collapsed areas.
Non-
Pressure Leaks
The only part of the brake system that could have a brake fluid loss that does not appear when the
system is under pressure is the brake master cylinder reservoir area. Brake fluid loss can be caused
by a missing or poorly- fitted brake master cylinder filler cap (2162), a punctured or otherwise damaged
brake master cylinder reservoir, a missing or damaged brake master cylinder filler cap gasket, or by
missing, damaged or poorly- fitted sealing grommets between the brake master cylinder (2140) and the
brake master cylinder reservoir.
The brake master cylinder reservoir grommets are not separately serviceable and must be installed
new as part of a new brake master cylinder reservoir.
Install a new flexible brake hose if it shows signs of softening, cracking or other damage.
When installing a new brake hose, position the hose to avoid contact with other vehicle components.
Road Test
Perform a road test to compare actual vehicle braking performance with the performance standards
expected by the driver. The ability of the test driver to make valid comparisons and detect performance
deficiencies will depend on experience.
The driver should have a thorough knowledge of brake system operation and accepted general
performance guidelines in order to make good comparisons and detect performance problems.
Select a road that is reasonably smooth and level. Gravel or bumpy roads are not suitable because the
surface does not allow the tires to grip the road equally. Avoid crowned roads.
A key factor in evaluating brake concerns is the deceleration rate. This varies from vehicle to vehicle
and with changes in operating conditions. It is evident how well the brakes are working after just a few
applications.
Avoid locking the brakes. Locked brakes are not an indication of braking efficiency.
Visual Inspection Chart Mechanical Electrical
z
Brake master cylinder
z Brake caliper piston
z Brake discs
z Brake pads z
Parking brake switch
z Damaged or corroded wiring harness
z Brake master cylinder fluid level switch Klj . 2 ba
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For low or spongy brake pedal concerns:
zcheck and, if necessary, refill the brake master cylinder reservoir.
z bleed the brake system and retest the brake pedal feel.
z if the brake pedal is still low or feels spongy, check the brake pedal mounting for looseness and
correct installation. Check the power brake booster and the brake master cylinder for loose
mounting. Correct as necessary and retest the system for normal operation.
For a slow or incomplete brake pedal return concern:
zinspect for binding, damage, correct installation or interference at the brake pedal.
z check the power brake booster for binding, damage and correct installation.
Vibration When Brakes are Applied
For vibration concerns when brakes are applied, perform the following procedure.
Visually inspect: ztire condition and pressure.
z suspension bushings and ball joints.
Correct as necessary. 1. Verify and isolate the concern. Brake roughness can be felt in: zthe steering wheel.
z the seat.
z the brake pedal.
2. After verifying the concern, check for related concerns in the: zOn- Line Automotive Service Information System (OASIS).
z Technical Service Bulletins.
3. Check wheel bearing end- play and correct as necessary.
4. NOTE: Begin at the front of the vehicle unless the vibration has been isolated to the rear.
Remove the tire and wheel.
5. Remove the brake caliper.
6. Measure and record the brake disc thickness. Install a new brake disc if the thickness after machining will be at or below specification. The specification is molded into the brake disc. Do z
Power brake booster
z Brake pedal linkage
z Vacuum booster hose
z Tires
z Foreign material Klj . 3 ba
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Always On
zParking brake.
z Brake fluid level.
z Vibration When
Brakes Are Applied z
Rear disc brakes.
z Front disc brakes. z
REFER to Section 100 -
04 .
z Brake Pedal Goes
Down Fast z
Brake fluid level. zFILL the brake master
cylinder reservoir.
BLEED the system.
z Air in system. zBLEED the system.
z Brake master
cylinder. z
PERFORM the brake
master cylinder
component test in this
section.
z The Brake Pedal
Eases Down Slowly z
Air in system. zBLEED the system.
REFER to Bleeding —
System in this section.
z Brake master
cylinder. z
PERFORM the brake
master cylinder
component test in this
section.
z Brake Lockup During
Light Brake Pedal
Force z
Disc brake
component.
z Parking brake
component.
z Anti- lock brake
control system. z
Go To Pinpoint Test C .
z Excessive/Erratic
Brake Pedal Travel z
Leak in hydraulic
system.
z Air in system.
z Disc brake caliper.
z Brake master
cylinder. z
Go To Pinpoint Test D .
z Brakes Drag zParking brake
component. z
REPAIR or INSTALL new
components as
necessary. REFER to
Section 206 - 05 .
z Disc brake caliper. zREPAIR or INSTALL a
new brake caliper as
necessary. REFER to
Section 206 - 03 and
Section 206 - 04 .
z Brake booster-to-
brake master
cylinder push rod
adjustment. z
ADJUST the push rod.
REFER to Section 206 -
07 .
z Brake master
cylinder. z
PERFORM the brake
master cylinder
component test in this
section.
z Excessive Brake
Pedal Effort z
Power brake
booster. z
PERFORM the brake
booster component test
in this section.
z Power brake
booster check
valve (2365). z
PERFORM the check
valve component test in
this section.
z Power brake
booster hose. z
REROUTE, REPAIR or
INSTALL a new brake Klj . 5 ba
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Pinpoint Tests
PINPOINT TEST A: THE BRAKES PULL OR DRIFT booster hose as
necessary.
z Red Brake Warning
Indicator Inoperative z
Circuit.
z Bulb. z
REFER to Section 413 -
01 .
z Brake Noise zDisc brake
component. z
MACHINE or INSTALL a
new brake component as
necessary. REFER to
Section 206 - 03 or
Section 206 - 04 .
z Hydro-Boost, No
Power Assist z
Power steering
pump.
z Linkage.
z Power steering
fluid flow.
z Hydro-boost unit. z
Go To Pinpoint Test E .
z Hydro-Boost Erratic
Operation, Sticks,
Binds or Grabs z
Supply hose.
z Hydro-boost unit. z
Go To Pinpoint Test F .
z Hydro-Boost Brake
System Operation
Suspect z
Leakage.
z Hydro-boost unit. z
Go To Pinpoint Test G .
Test Step Result / Action to Take
A1 CHECK THE TIRES
NOTE:
Check tire pressure with the brakes off.
z Check tires for uneven and excessive wear and for correct
pressure.
z Are the tires OK? Yes
GO to
A2 .
No
CORRECT as necessary.
RETEST for normal
operation. A2 CHECK THE ALIGNMENT
z
Check the caster, camber and toe. Refer to Section 204 -
00 . Yes
GO to
A3 .
No
CORRECT alignment as
necessary. REFER to Section 204 - 00 . RETEST for correct
operation. Klj . 6 ba
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z
Key in ON position.
z Does the brake warning indicator stay on? cylinder reservoir. TEST the
system for normal operation.
B2 CHECK PARKING BRAKE SWITCH
z
Key in OFF position.
z Disconnect: Parking Brake Switch.
z Key in ON position.
z Does the brake warning light stay on? Yes
GO to
B3 .
No
INSTALL a new parking brake
switch. TEST the system for
normal operation. B3 CHECK THE GEM
z
Key in OFF position.
z Disconnect: GEM C201e.
z Measure resistance to ground at C201e- 13.
z Is the resistance greater than 10,000 ohms? Yes
REPAIR the GEM. TEST the
system for normal operation.
No
For vehicles without Daytime
Running Lights (DRL), GO to
B4
. For vehicles with DRL, GO
to B5 .
B4 CHECK CIRCUITS 977 (VT/WH), 22 (LB/BK) AND 128
(VT/YE) z
Remove the fused jumper from C124.
z Measure the resistance to ground at C124- 2.
z Is the resistance greater than 10,000 ohms? Yes
REPAIR the ground short in
circuit 128 (VT/YE). TEST the
system for normal operation.
No
REPAIR the ground short in
circuit 977 (VT/WH) or circuit 22
(LB/BK). TEST the system for
normal operation.
B5 CHECK CIRCUIT 128 (VT/YE)
z
Remove the fused jumper from C124.
z Measure the resistance to ground at C201e- 13. Yes
GO to
B6 . Klj . 8 ba
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PINPOINT TEST C: BRAKE LOCKUP DURING LIGHT BRAKE PEDAL
FORCE z
Is the resistance greater than 10,000 ohms? No
REPAIR the ground short in
circuit 128 (VT/YE). TEST the
system for normal operation.
B6 CHECK DAYTIME RUNNING LIGHTS (DRL) MODULE
z
Disconnect: DRL Module C1030.
z Measure the resistance to ground at C124- 2.
z Is the resistance greater than 10,000 ohms? Yes
REPAIR the DRL module. TEST
the system for normal operation.
No
REPAIR the ground short in
circuit 22 (LB/BK) or 977
(VT/WH). TEST the system for
normal operation.
Test Step Result / Action to Take
C1 INSPECT THE TIRES
z
Inspect the tires for uneven or excessive
wear, correct pressure, correct size and
type.
z Are the tires OK? Yes
GO to
C2 .
No
CORRECT as necessary. RETEST for
normal operation. C2 CHECK THE BRAKE CALIPER
COMPONENTS z
Inspect the brake pads and brake discs for
wear, damage, contamination and correct
installation.
z Are the brake components OK? Yes
GO to
C3 .
No
CORRECT as necessary. RETEST for
normal operation. C3 CHECK THE PROPORTIONING VALVE
z
Install the gauges from the ABS brake and
pressure test kit on one front and one rear
bleeder screw.
z Apply 6895 kPa (1000 psi) to the front
brake system.
z Is the pressure in the rear system 3516- Yes
INSPECT the disc brake calipers and
INSTALL new calipers as necessary.
RETEST for normal operation.
No Klj . 9 ba
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PINPOINT TEST D: EXCESSIVE/ERRATIC BRAKE PEDAL TRAVEL
PINPOINT TEST E: HYDRO-
BOOST, NO POWER ASSIST 4481 kPa (510-
650 psi)? INSTALL a new proportioning valve.
RETEST for normal operation.
Test Step Result / Action to Take
D1 CHECK FOR SPONGY PEDAL
z
Key in ON position.
z Operate the brake pedal and note pedal feel.
z Does the pedal feel spongy? Yes
BLEED the brake system. REFER to
Bleeding —
System in this section.
RETEST for normal operation.
No
GO to D2 .
D2 CHECK THE BRAKE PEDAL
z
Inspect the brake pedal and bracket for
binding, obstruction or damage.
z Is the brake pedal OK? Yes
GO to
D3 .
No
REPAIR or INSTALL a new brake pedal as
necessary. RETEST for normal operation. D3 CHECK THE BRAKE COMPONENTS
z
Inspect the calipers bolts, anchor plate bolts
and anti- rattle springs for binding, damage,
contamination and correct installation.
z Are the bolts and springs OK? Yes
GO to
D4 .
No
REPAIR or INSTALL new components as
necessary. RETEST for normal operation. D4 CHECK THE BOOSTER AND MASTER
CYLINDER z
Check the power brake booster and brake
master cylinder for correct installation and
correct push rod adjustment. Refer to
Section 206 - 06 and to Section 206 - 07 .
z Are the power brake booster and the
brake master cylinder OK? Yes
INSPECT the front wheel bearings for
wear, damage and correct installation and
the rear axle end play. CORRECT as
necessary. RETEST for normal operation.
No
CORRECT as necessary. RETEST for
normal operation.
Test Step Result / Action to Take
E1 CHECK FLUID LEVEL IN POWER STEERING
PUMP z
Check fluid level in power steering pump.
z Is level within specification? Yes
GO to
E2 .
No
CHECK for leakage of power steering
fluid. ADD fluid as necessary. E2 CHECK ACCESSORY DRIVE BELT Klj . 10 ba
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