1991 MITSUBISHI 3000GT Service Manual

SERVICE BRAKES - Service Adjustment Procedures35-5514N0171
\\ \ \14NOO98]
14A04013
REAR BRAKE DISC THICKNESS CHECKM35FVA.D1. Remove dirt and rust from brake disc surface.
2. Measure disc thickness at 4 locations or more.
Standard value:
18.0 mm (-71 in.)
20.0 mm (.79 in.)
Limit:
16.4 mm (.65 in.)
18.4 mm (.72 in.)
Replace the discs and pad assembly for both sides left and
right of the vehicle if they are worn beyond the specified
limit.
REAR BRAKE DISC RUN-OUT CHECKM35FWAC
1.Remove the rear brake assembly, and support it by a wire,
etc.
2. Place a dial gauge approximately 5 mm
(.2 in.) from the
outer circumference of the brake disc, and measure the
run-out of the disc.
Limit: 0.08 mm
(.0031 in.) or less
NOTETighten nuts to secure the disc to the hub.
REAR BRAKE DISC RUN-OUT CORRECTIONM35FXAB
1.If the run-out of the brake disc is equivalent to or exceeds
the limit specification, change the phase of the disc and
hub, and then measure the run-out again.
NOTEThe procedures for checking by changing the installation
phase of the disc are the same as those for the front brake
discs. Note, however, that the axial play (limit) in the hub
differs. (Refer to
P.35-53.)Limit:
0.05 mm (.002 in.)
0.8 mm (.031 in.)
2.If the problem cannot be corrected by changing the phase
of the brake disc, replace the disc.
1 TSB Revision

35-56SERVICE BRAKES - Service Adjustment Proceduresi
14N0179
\14N008Ei
BRAKE LINING THICKNESS CHECKM35FIAD
1.Remove the rear brake assembly, and support it by a wire,
etc.
2. Remove the brake disc.
3.
L?jMeasure the wear of the brake lining at the place worn the
most.
Standard value: 2.8 mm
(.I1 in.)
Limit:
1.0 mm (-04 in.)
Replace the shoe and lining assembly if brake lining
thickness is less than the limit and/or if it is not worn evenly.
Caution
Whenever the shoe and lining assembly is replaced,
replace both RH and LH assemblies as a set to prevent
car from pulling to one side when braking.
BRAKE DRUM INSIDE DIAMETER CHECKM35FJAD
1.Remove the rear brake assembly, and support it by a wire,
etc.
2. Remove the brake disc.
3. Measure the inside diameter of the hub and drum at two or
more locations.
Standard value: 168.0 mm (6.6 in.)
Limit: 169.0 mm (6.7 in.)
Replace brake drums and shoe and lining assembly when~~
wear exceeds the limit value or is badly imbalanced.
BRAKE LINING AND BRAKE DRUM CONNECTION
CHECK~M35FPAD
1.Remove the rear brake assembly, and support it by a wire,
etc.
2. Remove the brake disc.
3. Remove the shoe and lining assembly.
4. Chalk inner surface of brake disc and rub with shoe and
lining assembly.
5. Replace shoe and lining assembly or brake disc if very
irregular contact area.
NOTEClean off chalk after check.
TSB Revision

SERVICE BRAKES - Service Adjustment Procedures35-57
i
~18~17~16~15~14~13~12~11~10~ 9 18 I 7 16 I 5 14 13 12 1 1 1[35~34~33~32~31~30~29~28~27~26~25~24~23~22~21~20~19~Check connector
ECU
/m/Body harness
MB991 35614N018(
I I I 2When turned manually
~---~---~-.-~---[--.I 1MEASUREMENT OF
WHEEL SPEED SENSOR
OUTPUT VOLTAGEM35FOAO
1. Lift up the vehicle and release the parking brake.
2.Disconnect the ECU harness connector and measure with
the adapter harness (MB991 356) connected to the harness
side connector.
Caution
1. Never insert a probe, etc. into the connector as it
may result in poor contact later.
2.Do not connect the connector (Special Tool) markedwith “r+”except when recording the waveform on a
driving test. In such a case, connect the connector
to the ECU.
Terminal No. (same for AWD and FWD)
FL
RRFRRL
4
24218
52623393. Manually turning the wheel to be measured by
112 to 1
turn/second, measure the output voltage with a circuit
tester or oscilloscope.
Output voltage:
When measured with circuit tester: 70
mV or more
When measured with oscilloscope (max. voltage): 100
mV or more
Probable causes of low output voltage
l Speed sensor pole piece-to-rotor clearance too large
l Faulty speed sensor
4. Then, in order to observe the output state of the wheel
speed sensors, shift into low gear
(AWD vehicle) and drive
the wheels, observe the output voltage waveform of each
wheel speed sensor with an oscilloscope.
In the case of the FWD vehicle, observe the waveform with
an oscilloscope; for the front wheels, shift into low gear and
drive the wheels; for the rear wheels, turn the wheels
manually at a constant speed.
NOTE
1.Waveform may also be observed by actually driving the
vehicle.
2.The output voltage is low when the wheel speed is low
and increases as the wheel speed increases.
TSB Revision

35-58SERVICE BRAKES - Service Adjustment Procedures
POINTS IN WAVEFORM MEASUREMENT
Symptom
Too small or zero waveform
amplitudeProbable causes
Faulty wheel speed sensorRemedy
Replace sensor
Incorrect pole piece-to-rotor clearance
Adjust clearance
Waveform amplitude fluctuates
excessively (this is no problem ifAxle hub eccentric or with large runout
Replace hub
the minimum amplitude is
100 mV
or more)
Noisy or disturbed waveformOpen circuit in sensor
Open circuit in harness
Incorrectly mounted wheel speed sensor
Rotor with missing or damaged teethReplace sensor
Correct harness
Mount correctly
Replace rotor
NOTEThe wheel speed sensor cable moves following motion of the front or rear suspension. Therefore, it is likely that it has an
open circuit only when driving on rough roads and it functions normally on ordinary roads. It is, therefore, recommended
to observe sensor output voltage waveform also under special conditions, such as rough road driving,
(ME!991 377)12FOO5i
INSPECTION OF HYDRAULIC UNITINSPECTION BY FEEL
(I) Jack up the vehicle and support the vehicle with rigid racks
placed at the specified jack-up points.
(2) Release the parking brake and determine the drag force
(drag torque) of each wheel by feel.
LJ(3) Set the MUT through the adapter harness (MB991377) as
illustrated.
(4) After confirming that the shift lever or selector lever is in
the neutral position, start the engine.
The ABS warning light lights up, it goes into the MUT mode.
In the MUT mode, ABS does not function.
(5) Operate the MUT to force the actuator to operate (item No.
04, 05, 06).
(6) Turning the wheel manually, check the change of the
braking force when the brake pedal is depressed.
The change should be as shown in the following illustration.
NOTEWhile the ABS is in the fail safe mode, the MUT actuator
test cannot be made.
TSB Revision

SERVICE BRAKES- Service Adiustment Procedures35-59
iPressure decrease
Release
pjgKq LockDrag force when
pedal is releasedMUT actuator
itest start
3 sec.
I3 sec.
Pedal operation
Pedal operation
pattern @
pattern @
JJ.r__---------------
I
I
I
I----------
------------------4
I1r-’ - - - - - - - - - a -I6 sec.
1------ __---____-__ - --___-__--_ ---J’-
14FOO96(7) If any abnormality is found in the check, take corrective
action according to the following “Judgement in Inspection
by Feel” table.
Judgement in Inspection by Feel
No.
I IMUT display
04FR VALVE
M
05FL VALVEM
t
106”
I IRear VALVEM”Operation
(1) Depress brake pedal to
lock wheel.
(2) Using the MUT. select
the wheel to be checked
and force the actu-
ator to operate.
(3)Turn the selected wheel
manually to check the
change of brake force.
1-1 ‘gkte / Remedy
Normal
Brake force
released for 6
seconds after
locking.Wheel doesClogged brake Check and
not lock when
line other than clean brake
brake pedal HUline
is depressed.
Clogged
hy-Replace HU
draulic circuit assembly
in HUBrake force is
Incorrect HUConnect
not releasedbrake tubecorrectly
connection
HU solenoid
valve not
functioning
correctlyReplace HU
assembly
NOTE*: FWD
TSB Revision

35-60SERVICE BRAKES - Service Adjustment Procedures
INSPECTION BY USING BRAKE FORCE TESTER
NOTE
(1) The brake force tester roller and tire must be dry during the
test.
(2) When testing the front brakes, apply the parking brake and
when testing the rear brakes, apply chocks to the front
wheels to lock them.
(I) Place the front or rear wheels on the brake force tester
roller.(2) Set the MUT through the adapter harness
(MB9913771 as
illustrated.
(3) After confirming that the shift lever or selector lever is in
the neutral position, start the engine.
(The ABS warning light lights up, it goes into the
-MUTmode. In the MUT mode, ABS does not function.)
(4) Operate the brake force tester roller.
(5) Depress the brake pedal until the brake force tester
indicates the following value and keep the brake force at
this level during the test.
Front wheels: 1,000 N (220
Ibs.)Rear wheels: 650 N (143
Ibs.)(6) Allow the brake tester indication to stabilize before operat-
ing the MUT to perform actuator test (Item No. 01,
02, 03).
Then, read change of tester indication.
Referring to the following “Judgement in Inspection by
Using Brake Force Tester” table, judge and take corrective
action if necessary.
NOTEWhile the ABS is in the fail safe mode, the MUT actuator
test cannot be made.
1 TSB Revision

SERVICE BRAKES - Service Adiustment Procedures35-61
?ic.-
5Y
:6
iW
1
:f5
EF ‘.w g.-.sZE a,E.Y&
6?--
zF.c m%G
ii5
-:z
423_-5WGt:WC.c w g
?g&=230$5;
'5 E.o-o.s 2w= g
9; 8.,o L-0v)CW." $5c+wOCm‘.G s 5Fm”a,gg” :002wars,v.-‘X 0‘E‘U-t +-d‘0 c’-.wougzz0”
.c2.EG EXig 2 5
wg $-c w L+-Qv,P$?-F‘Z m+-S&C
.$f E.g +likQ-o’‘0 w
w w.2
2y w i;,225 &QCnWY+p=sCWQ'E-wowp,;Z& ge
O.--2-c“--5
0E
F
PmcnrmQW
Y2Q
&50
E=m
%5
E
:z=m
2
z
5'5
z
2zW
z
1 TSB RevisionI

When energized
Between terminals 4 and 5Continuity
When de-energized
Between terminals 4 and 5\i fl \\ 16FO264No continuity
Between terminals 1 and 3Continuity
16FO122L--J18FOCII
SERVICE BRAKES - Service Adjustment ProceduresI
INSPECTION OF POWER RELAYM35FOAP
7
1.Remove the relay box cover in the engine compartment and
remove the power relay.
2. Apply the battery voltage to the terminal @ and check for
‘L-J1
continuity between the following terminals when the
terminal @ is short-circuited to ground.
35-62
14FOOS14FOO8
l-TSB
1
REMEDY IN CASE OF DISCHARGED BATTERY
M35FOAQIf the engine is jump-started, because of a completely
discharged battery, the vehicle may suffer misfiring and fail to
start if an attempt is made to start without allowing the battery
to recover sufficiently. This is because the ABS consumes a
great deal of current for its self check. In such a case, allow the
battery to sufficiently charge or remove the ABS power relay in
the engine compartment to disable the ABS. Removing the
ABS causes the ABS warning light to light. After the battery is
charged sufficiently, install the power relay and restart the
engine to check that the ABS warning light goes out.
INSPECTION OF VALVE RELAY AND MOTOR
RELAY (ABS)M35FOAR1. Remove the splash shield
(FR) and remove the relay box
cover by inserting a screwdriver between the hydraulic unit
and cover to pry off the lock.
2.Remove the relays. The one closest to you (larger one) is
the motor relay and the one farthest from you (smaller one)
is the valve relay.
‘d~ i
wision