![](../../../img/35/AC000870AC00ENG.png)
![](../../../img/35/AC000871AC00ENG.png)
![](../../../img/35/AC000872AC00ENG.png)
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1.Carry out the simplified
brake booster operation check in the following
procedure: (1)
Run the engine for 1 to 2 minutes, and then stop. Depress
the brake pedal with normal
depression force. The result is judged as "Good" when the
pedal stroke is great at the first
depression, and becomes smaller as you repeat depressing the
pedal. If the pedal stroke does
not change, the result is judged as "No Good." (2)
With the engine stopped, depress the brake pedal several
times. Keep the brake pedal depressed
and start the engine. At this time, when the pedal moves
down slightly, the result is judged
as "Good." The result is judged as "No Good" if the pedal
does not moves down. (3)
With the engine running, depress the brake pedal. Stop the
engine in this condition. The
result is judged as "Good" when the pedal height does not
change for approximately 30 seconds.
The result is judged as "No Good" if the pedal moves
up. 2.The brake booster is judged as normal when
the results of all the above checks are
"Good." When one or more of the above check results are
"No Good," then the check valve, vacuum
hose, or brake booster is suspected faulty.
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1.Before starting this
inspection, remove the brake booster check valve from the
vehicle
and check its operation (Refer to
<LHD>,
<RHD>).
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![](../../../img/35/AC610136AB00ENG.png)
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2.After checking, install
the check valve to the vacuum hose and connect it to the
vacuum
gauge. Install special tool booster test adapter (MB992146)
to the brake booster and connect
it to the vacuum gauge. Connect the pressure gauge and pedal
depression gauge as shown in the
figure. Bleed the pressure gauge and then perform the
following tests: (1)
Airtightness test with no load Start the engine, and stop
it when the vacuum gauge indicator has reached approximately
-67
kPa. The result is judged as "Good" when the drop of the
vacuum approximately 15 seconds after
the engine was stopped is within -3.3 kPa. (2)
Airtightness test with load Start the engine and depress
the brake pedal with 200 N. Stop the engine when the vacuum
gauge indicator reached approximately -67 kPa. The
result is judged as "Good" when
the drop of the vacuum approximately 15 seconds after the
engine was stopped is within -3.3
kPa. When one or more of the above check results are
judged as "No Good," the vacuum hose or
brake booster is suspected faulty. (3)
Brake booster characteristics test Perform this test
after the above (1) and (2) were performed. .....1.
Non-servo effect test With the engine stopped, make sure
that the vacuum gauge reading is 0 kPa. Depress the
brake pedal with 100 N and 300 N, and measure the fluid
pressure generated.
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Standard
value:
Item
|
Pedal
depression
force
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100
N
|
300
N
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Generated fluid
pressure kPa
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0 -
600
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1,030 -
2,220
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.....2.
Servo effect test Start the engine. Depress the brake
pedal with 100 N and 300 N when the vacuum gauge indicator
reached approximately -67 kPa, and measure the fluid
pressure generated.
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Standard
value:
Item
|
Pedal
depression
force
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100
N
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300
N
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Generated fluid
pressure kPa
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6,570 -
8,330
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10,370 -
11,560
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