Toyota Tundra Service Manual: Brake Actuator Operation Sound is Loud during Initial Check

CAUTION / NOTICE / HINT

NOTICE:

When replacing the skid control ECU (brake actuator assembly), perform system variant learning and acceleration sensor zero point calibration.

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PROCEDURE

(a) After turning the ignition switch to ON, compare the operating sound of the brake actuator the first time the vehicle speed reaches 9 km/h (6 mph) with a known good vehicle of the same model.

OK:

The operating sound is the same or quieter than that of a known good vehicle of the same model.

HINT:

When the vehicle speed reaches approximately 9 km/h (6 mph), the initial check of the brake actuator assembly is performed and pump motor operation sounds are generated.

OK

END

NG

(a) Check that the cushion of the brake actuator bracket assembly is not worn, damaged or deformed.

OK:

The brake actuator bracket assembly is not worn, damaged or deformed.

NG

REPLACE BRAKE ACTUATOR BRACKET ASSEMBLY

OK

(a) Drain the brake fluid.

(b) Disconnect all brake lines from the brake actuator assembly.

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(c) Connect each brake line so that the cushion of the brake actuator assembly is tensioned evenly.

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NOTICE:

After connecting all the brake lines, add brake fluid and bleed the brake system.

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HINT:

By reducing the tension on the brake lines and cushion, the operating sound of the brake actuator assembly may be reduced.

(d) Check that no brake lines interfere the vehicle body or other components.

NEXT

(a) Perform a road test and check the magnitude of the operating sound again.

OK:

The operating sound is the same or quieter than that of a known good vehicle of the same model.

OK

END

NG

REPLACE BRAKE ACTUATOR ASSEMBLY