2003 FORD MUSTANG wheel

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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not machine a new brake disc.
7. For vehicles with a two- piece hub and brake disc assembly:
z Match-mark before disassembly.
z Remove the brake disc.
z Using a die grinder with a mild abrasive (Scotch Brite® type), remove any rust or
corrosion from the hub and brake disc mounting surfaces.
z Align the match- marks and reinstall the brake disc on the hub.
8. CAUTION: Do not use a bench lathe to machine brake discs.
NOTE: The depth of cut must be between 0.10 and 0.20 mm (0.004 and 0.008 inch). Lighter
cuts will cause heat and wear. Heavier cuts will cause poor brake disc surface finish.
Using on- vehicle brake lathe, machine the brake discs. Follow the manufacturer's instructions.
After machining, make sure the brake disc still meets the thickness specification.
9. Using a dial indicator, verify that the brake disc lateral runout is now within vehicle specification.
10. Remove any metal chips.
11. Remove the hub adapter.
12. Remove any remaining metal chips from the machining operation.
13. CAUTION: Do not carry out this step on rear drum- in-hat brake discs.
For vehicles with a two- piece hub and a non drum- in-hat brake disc assembly:
z Remove the brake disc from the hub.
z Remove any remaining metal chips from hub and brake disc mounting surfaces and from
the ABS sensor.
z Apply High Temperature Nickel Anti- Seize Lubricant F6AZ-9L494-AA to the mounting
surfaces.
z Using the match- marks, mount the brake disc on the hub.
14. Install the caliper and check brake operation.
Symptom Chart Symptom Chart
Condition
Possible Sources Action
z The Brakes Pull or
Drift z
Tire air pressure.
z Wheel alignment.
z Brake pads.
z Brake components.
z Suspension
component. z
Go To Pinpoint Test A .
z The Red Brake
Warning Indicator Is z
Instrument cluster.
z Circuit. z
Go To Pinpoint Test B . Klj . 4 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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Component Tests
Brake Booster
1. Check the hydraulic brake system for leaks or insufficient fluid.
2. With the transmission (7003) in NEUTRAL, stop the engine (6007) and apply the parking brake control (2780). Apply the brake pedal several times to exhaust all vacuum in the system.
3. Apply the brake pedal and hold it in the applied position. Start the engine. If the vacuum system is operating, the brake pedal will tend to move downward under constant foot pressure. If no
motion is felt, the power brake booster system is not functioning. Continue with the following
steps.
4. Remove the vacuum booster hose from the check valve connection. Manifold vacuum must be available at the check valve end of the vacuum booster hose with the engine at idle speed and
the transmission in NEUTRAL. If the manifold vacuum is available to the power brake booster,
connect the vacuum booster hose to the power brake booster check valve and repeat Steps 2
and 3.
5. If no downward movement of the brake pedal is felt, install a new power brake booster.
6. Operate the engine a minimum of 10 seconds at fast idle. Stop the engine, and let the vehicle stand for 10 minutes. Then apply the brake pedal with approximately 89 N (20 lb) of force. The
brake pedal feel should be the same as that noted with the engine operating. If the brake pedal
feels hard (no power assist), install a new power brake booster check valve and retest. If the
brake pedal feels spongy, bleed the hydraulic system to remove air. For additional information,
refer to Bleeding — System in this section. Check Valve z
Engine running at idle speed.
z CAUTION: Do not hold the brake pedal at 444 Nm
(100 lb) force for more than 5 seconds at a time.
z Apply brake pedal with approximately 444 Nm (100 lb)
force and hold.
z Check hydro-boost unit input seal, housing seal,
accumulator seal, piston seal and spool plug seal for
leakage.
z Is hydro- boost unit free of leaks? Yes
GO to
G6 .
No
INSTALL a new hydro- boost
unit. G6 CHECK RESERVE RETENTION
z
Engine running at idle speed.
z CAUTION: Do not hold the brake pedal at 444 Nm
(100 lb) force for more than 5 seconds at a time.
z Charge system to pressure by holding the steering wheel at
stop or by pressing the brake pedal with approximately 444
Nm (100 lb) force.
z Key in OFF position.
z Wait five seconds.
z Press brake pedal and observe if there is any power brake
reserve.
z Is there any power brake reserve? Yes
Hydro-
boost unit is OK.
No
INSTALL a new hydro- boost
unit. Klj . 13 ba
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Four Wheel Anti-
Lock Brake System (4WABS) Hydraulic Control Unit (HCU)
NOTE: This procedure only needs to be performed if the 4- wheel anti-lock brake (4WABS) hydraulic
control unit (HCU) has been installed new or if the HCU lines have been opened.
1. Clean all dirt from and remove the brake master cylinder filler cap (2162), and fill the brake master cylinder reservoir (2K478) with the specified brake fluid.
2. Connect a clear waste line to the RH rear bleeder screw (2208) and the other end in a container partially filled with recommended brake fluid.
3. Loosen the RH rear bleeder screw until a stream of brake fluid comes out. While the assistant maintains pressure on the brake pedal (2455), tighten the RH rear bleeder screw.
zRepeat until clear, bubble- free fluid comes out.
z Refill the brake master cylinder reservoir as necessary.
4. Tighten the RH rear bleeder screw, and disconnect the waste line. Klj . 4 ba
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GENERAL PROCEDURES
Runout Check —
Brake Disc and Hub
CAUTION: The brake disc (1126) runout specification must be met to ensure correct brake
performance without roughness complaints.
CAUTION: Do not install brake discs that are less than the minimum thickness specified.
Do not machine a brake disc below the minimum thickness specification.
NOTE: When installing brake discs, always align the painted match marks on the brake discs with
those on the front hub or rear axle.
NOTE: When installing brake discs, always apply anti- seize lubricant to the brake disc-to-front hub or
to the brake disc- to-rear axle mating surfaces.
1. Do not remove the tire and wheel assembly. Tighten the wheel nuts to specification with a torque stick or torque wrench.
2. Raise and support the vehicle.
3. Assemble the Brake Measurement Kit, using the spherical tip extension.
4. Locate an opening on the inboard side of the dust shield that will allow the dial indicator tip to be positioned at least 5 mm (0.2 inch) from the outer edge of the brake disc.
5. NOTE: Do not clamp the gauge set to a vehicle component separated from the brake disc by a
flexible joint, such as a ball joint or body mount.
Clamp the Brake Measurement Kit on the vehicle, making sure the flexible indicator arm and
probe tip do not touch the dust shield or tire while rotating.
6. NOTE: For rear wheel measurement only, have an assistant push in on the wheel cover or axle
shaft center while rotating the wheel.
Rotate the wheel for six revolutions, and record the total indicated runout.
SECTION 206-
00: Brake System — General Information 2003 Mustang Workshop Manual Special Tool(s)
Brake Measurement Kit
134-R0199 or equivalent
Material Item Specification
High Temperature Nickel Anti-
Seize Lubricant
F6AZ-
9L494- AA ESE-
M12A4-
A Klj . 1 ba
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7. If the total indicated runout exceeds the maximum specification, remove the brake disc. For
additional information, refer to Section 206 - 03 for front or to
Section 206 - 04 for rear.
8. Clean the brake disc mounting face of dirt, rust and foreign material.
9. For front wheels, measure and record the total indicated runout of the hub face outside the stud circle.
10. Install a new front hub if the total indicated runout exceeds the maximum specification. For additional information, refer to Section 204 - 01 .
z Repeat the hub runout measurement.
11. NOTE: Clean the axle flange surface before measuring.
NOTE: For rear wheels, press inward on the axle shaft while measuring the rear axle runout.
For rear wheels, measure and record the total indicated runout at a point on the axle shaft
outside the stud circle.
12. If the total indicated runout exceeds the maximum specification, inspect the rear axle. For additional information, refer to Section 205 - 00 . Repair as necessary.
z Repeat the rear brake disc runout measurement. Klj . 2 ba
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