2003 FORD MUSTANG steering

PINPOINT TEST F: HYDRO-
BOOST ERRATIC OPERATION, STICKS,
BINDS OR GRABS z
Check accessory drive belt tension and
condition. Refer to Section 303 - 05 .
z Is the accessory drive belt OK? Yes
GO to
E3 .
No
INSTALL a new accessory drive belt.
REFER to Section 303 - 05 .
E3 CHECK POWER STEERING HOSES
z
Check power steering pressure hoses, power
steering gear pressure hoses and power
steering return hose for cracks or leaks.
z Do power steering pressure hose, power
steering gear hose and power steering
return hose check OK? Yes
GO to
E4 .
No
INSTALL new hoses as necessary.
REFER to Section 211 - 00 .
E4 CHECK BRAKE PEDAL LINKAGE
z
Check brake pedal linkage for binding or
sticking operation.
z Does pedal linkage check OK? Yes
GO to
E5 .
No
INSTALL new pedal linkage as necessary.
REFER to Section 206 - 06 .
E5 CHECK POWER STEERING PUMP SPEED
z
Check engine idle speed against
specifications.
z Is engine idle speed OK? Yes
GO to
E6 .
No
SET engine idle speed to specification.
REFER to Powertrain Control/Emissions
Diagnosis (PC/ED) manual. E6 CHECK FOR PLUGGED RETURN HOSE
z
NOTE: The return hose from the oil cooler to
the power steering reservoir has an in- line
filter in the hose.
z Disconnect power steering return hose from
power steering fluid cooler and power
steering pump reservoir.
z Pass air through hose from the oil cooler end.
z Is hose plugged? Yes
INSTALL a new power steering return
hose.
No
GO to
E7 .
E7 CHECK POWER STEERING PUMP FLOW
AND RELIEF z
Test power steering pump for correct flow
and relief pressure. Refer to Section 211 - 00 .
z Is power steering pump operating
correctly? Yes
INSTALL a new power brake hydro-
boost
unit. REFER to Section 206 - 07 .
No
INSTALL a new power steering pump.
REFER to Section 211 - 02 .
Test Step Result / Action to
Take F1 CHECK SUPPLY HOSE
z
Check for obstructions in power steering return hose and Yes Klj . 11 ba
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PINPOINT TEST G: HYDRO-
BOOST BRAKE SYSTEM OPERATION
SUSPECT connections between the power steering pump reservoir and
between the power steering pump reservoir and the hydro-
boost
power brake booster.
z Are there any obstructions? REMOVE
obstructions or
INSTALL a new
hose.
No
GO to
F2 .
F2 CHECK BOOSTER OPERATION
z
Have an assistant check the fluid in the power steering pump
reservoir while rapidly applying the brake pedal approximately one
inch.
z Does the fluid show any movement or spouting? Yes
System OK.
No
INSTALL a new
hydro-boost
assembly. Test Step Result / Action to Take
G1 CHECK BASIC OPERATION
z
Key in OFF position.
z Press and release brake pedal several times to deplete all
hydraulic pressure from the hydro- boost power brake
booster.
z Press and hold brake pedal with light pressure.
z Key in START position.
z Does the brake pedal fall slightly and hold, and is less
pressure now required to hold brake pedal at the new
position? Yes
Hydro-
boost is OK.
No
GO to G2 .
G2 CHECK FOR HYDRAULIC BRAKE LEAK
z
With engine running, press and release brake pedal several
times.
z Hold brake pedal down with medium pressure, 34- 47 Nm
(25- 35 lb- ft).
z Does brake pedal move toward floor? Yes
GO to
G3 .
No
GO to G4 .
G3 CHECK FOR LEAKS —
BRAKE FLUID LINES z
Check for leaks at brake lines, including brake master
cylinder and brake hose.
z Do components check OK? Yes
COMPLETE master cylinder
By-
Pass Condition Test in
this section.
No
INSTALL new hoses and
lines as necessary. G4 CHECK HYDRO-
BOOST CONNECTIONS z
Clean the hydro- boost power brake booster, power steering
pressure hose, power steering gear pressure hose and
power steering return hose and connection.
z Start engine and run at idle.
z Check hose connections for leakage.
z Do hose connections check OK? Yes
GO to
G5 .
No
REPAIR or INSTALL new
hose and connections as
necessary. G5 CHECK FOR HYDRO-
BOOST LEAK Klj . 12 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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7. Bleed each brake tube at the brake master cylinder as follows:
1. Have an assistant pump the brake pedal, and then hold firm pressure on the brake pedal.
2. Loosen the rear most brake tube fittings until a stream of brake fluid comes out. While the assistant maintains pressure on the brake pedal, tighten the brake tube fitting.
3. Repeat this operation until clear, bubble- free fluid comes out.
4. Refill the brake master cylinder reservoir as necessary. Repeat the bleeding operation at the front brake tube.
Master Cylinder Priming — 4.6L
1. CAUTION: Use only bleed screws on the engine side of the brake master cylinder
(2140). The hydro- boost bleed screw, located near the dash on the hydro- booster
casting, is for the booster cavity filled with power steering fluid, not brake fluid.
Connect a clear waste line to the bleed screw closet to the booster first and the other end in a
container partially filled with recommended brake fluid.
2. Open the bleeder screw, have an assistant push the brake pedal down slowly through full travel, close the bleeder screw, then return brake pedal slowly to full released position. Wait five
seconds, then repeat operation until air bubbles cease to appear.
3. Repeat Step 2 for bleeder screw farthest from hydro- booster. Klj . 3 ba
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SPECIFICATIONS
SECTION 206-
07: Power Brake Actuation 2003 Mustang Workshop Manual Torque Specifications
Description Nm lb-
ft Power brake booster nuts 25 19
Brake master cylinder nuts 25 19
Hydraulic tube connections 17 13
Power steering pressure lines 19 14 Klj . 1 ba
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DESCRIPTION AND OPERATION
Brake Booster —
Hydro-Boost
The Hydro- Boost brake booster is a hydraulically operated brake booster powered by the power
steering pump (3A674). The power steering pump provides the fluid pressure to operate both the
power brake booster and the power steering gear (3504).
A Hydro- Boost reserve system (accumulator) stores sufficient fluid under pressure to provide at least
two power- assisted brake applications in the event the power steering pump fluid flow is interrupted.
For low assist concerns on vehicles equipped with the Hydro- Boost system, refer to Section 211 - 00 to
check the power steering pump pressure and flow.
The brakes can also be applied manually if the reserve system is depleted.
Any leakage goes directly back to the power steering pump reservoir (3E764). SECTION 206-
07: Power Brake Actuation 2003 Mustang Workshop Manual Item Part Number Description
1 2140 Master cylinder
2 2B559 Hydro-Boost Klj . 1 ba
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GENERAL PROCEDURES
Hydro-
Boost Bleeding
1. NOTE: The Hydro- Boost power brake booster (2B560) is generally self- bleeding, and the
following procedure will normally bleed the air from the power brake booster. Normal operation
of the vehicle will further remove any additional trapped air.
Fill the power steering oil reservoir (3A697) with MERCON® Multi- Purpose ATF XT-2-QDX or
MERCON® equivalent.
2. Remove the powertrain control module (PCM) fuse to prevent the engine from starting.
3. Crank the engine for several seconds.
4. Check the fluid level in the power steering oil reservoir and add if necessary. Install the powertrain control module (PCM) fuse.
5. Start the engine.
6. With the engine running, turn the steering wheel (3600) from stop- to-stop twice. Turn the engine
off.
7. Depress the brake pedal (2455) several times to discharge the accumulator.
8. Repeat Steps 5 and 6.
9. If foaming occurs, stop the engine and allow the foam to dissipate.
10. Repeat Steps 5 and 6 as required, until all the air is removed from the system (when the foaming stops).
SECTION 206-
07: Power Brake Actuation 2003 Mustang Workshop Manual Klj . 1 ba
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5. Disconnect the power steering return line hose (3A005).
6. Disconnect the power steering pressure lines.
7. Remove the self-
locking pin.
8. Remove the stoplight switch (13480) and the brake booster push rod from the brake pedal pin. Klj . 2 ba
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