TOYOTA PREVIA 91-97 REPAIR MANUAL

9-42 BRAKES

Actuator

REMOVAL & INSTALLATION

1. Disconnect the brake lines leading to the actuator.


2. Disconnect the electrical wiring attached to the actuator.


3. Remove the bolts and extract the actuator from the vehicle,
   the nuts retaining the bracket to the unit.
   To install:


4. Attach the bracket to the actuator, tighten to 48 inch Ibs. (5


5. Secure the actuator with bracket to the vehicle and tighten 1
   to 14 ft. Ibs. (19 Nm).


6. Attach the electrical wiring to the unit.


7. Attach the brake lines and tighten each to 11 ft. Ibs. (15 Nm


8. Fill the brake master cylinder reservoir with new brake fluid
   the system and check for leaks.

Remove

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e bolts

Bleed

ABS ECM

The ABS ECM can be located in the front engine compartment.

REMOVAL & INSTALLATION

1. If the van is equipped with a C/D player, remove the amplifier to
   access the ABS ECM.


2. Remove the ABS ECM cover (if equipped) and the computer from the
   mounting bracket.


3. Disconnect the wiring from the ECM and remove the compij er from
   the vehicle.
   To install:


4. Connect the harnesses and insert the wiring harness to the it amp.


5. Position the computer and install it with the 5 screws, tighteji them to
   48 inch Ibs. (5 Nm).


6. Install the computer cover, if equipped.


7. Install the C/D amplifier if equipped.

Deceleration Sensor

TESTING

f»The following procedures require driving the vehicle while it is in
the diagnostic mode. The anti-lock system will be disabled; only
normal braking function will be available.

1. Check the battery voltage with the engine OFF; voltage shou be
   approximately 12 volts.


2. With the ignition switch ON, make certain the ABS warning limp
   comes on for about 3 seconds and then goes out on 1991-93 mod I's and
   4 times every 1 second on 1994-97 models.


3. Apply the parking brake fully, depress the brake pedal and start the
   engine.


4. After a short delay, the ABS dashboard warning lamp should flash
   about once every second. This is slower than the usual system flashing
   when transmitting a code.


5. Release the parking brake and drive the vehicle straight ahead at 12.4
   mph (20 kph) or greater speed. Lightly depress the brake pedal; there
   should be no change in the flashing dashboard lamp.


6. Continue to drive at the same speed and apply the brakes moderately.
   The warning lamp should stop flashing and remain on during braking only.
   Once the brake is released, flashing continues at the previous rate.


7. Continue driving at the same speed; apply the brakes strongly. The
   dash warning lamp should remain on during the braking period and change
   to a rapid flash when the brakes are released.


8. If the warning lamp display does not meet specifications, check the
   installation of the deceleration sensor. It must be correctly and securely
   installed. If installation is proper, replace the sensor and retest the system.


9. Stop the vehicle and turn the ignition switch OFF. Remove the
   jumper wire from the check connector.

Sensor Ring (Rotor)

REMOVAL & INSTALLATION

The wheel mounted sensor rings are integral parts of either the wheel

hub or the axle shaft; if the ring is damaged, the hub or shaft must be

replaced. For axle shaft and wheel hub removal and installation procedures,

please refer to the appropriate section of this repair manual.

Bleeding The ABS System

The brake fluid reservoir is located on top of the master cylinder. While

no special procedures are needed to fill the fluid, the reservoir cap and sur-

rounding area must be wiped clean of all dirt and debris before removing

the cap. The slightest dirt in the fluid can cause a system malfunction. Use

only DOT 3 fluid from an unopened container. Use of old, polluted or non-

approved fluid can seriously impair the function of the system.

Bleeding is performed in the usual manner, using either a pressure

bleeder or the 2-person manual method. If a pressure bleeder is used, it

must be of the diaphragm type with an internal diaphragm separating the

air chamber from the fluid. Tighten each bleeder plug to 74 inch Ibs. (8

Nm).

Always begin the bleeding with the longest brake line, then the next

longest, and so on. If the master cylinder has been repaired or if the reser-

voir has been emptied, the master cylinder will need to be bled before the

individual lines and calipers. During any bleeding procedure, make certain

to maintain the fluid level above the MIN line on the reservoir. When the

bleeding procedure is complete, fill the reservoir to the MAX line before

reinstalling the cap.