MAZDA 626 1987 Workshop Manual

POWER BRAKE UNIT 1 1
76G11X-034
INSPECTION OF CHECK VALVE
Note (MTX)
The check valve is pressed into the vacuum
hose. There is an arrow on the hose surface
to indicate direction of installation.
Inspection
1. Disconnect the vacuum hose from the engine.
2. Apply suction and pressure to the hose from the
engine side. Check that air flows only toward the
engine.
If the air passes in both directions or not at all, re-
place the check valve (along with the hose).
REMOVAL
Remove in the sequence shown in the figure, referring to removal note for specially marked parts.
1. Fluid level sensor connector
2. Vacuum switch coupler
(RF, RF-CX)
3. Brake pipe
4. Master cylinder
5. Clutch pipe holder
6. Vacuum hose and check
valve
7. Clevis pin
8. Steering shaft
76G11X-069
9. Power brake unit
10. Gasket
11. Locknut
12. Operating lever
11-29

1 1 POWER BRAKE UNIT
Removal Note
Steering Shaft
To remove the mounting nuts of the power brake unit,
the steering shaft must be removed. (Refer to page
10—22 for removal and installation procedures.)
76G11X-102
DISASSEMBLY AND ASSEMBLY
1. Disassemble in the sequence shown in the figure, referring to disassembly note for specially marked
parts.
2. Inspect each part, referring to inspection note.
3. Assemble in the reverse order of disassembly, referring to assembly note for specially marked parts.
8.8—13 N-m (90-130 cm-kg, 78—112 in-lb)
1. Dust boot
2. Rear shell assembly
3. Retainer
4. Bearing
5. Dust seal
6. Retainer
7. Air filters
8. Air silencer
9. Diaphragm and plate
10. Power piston assembly
11. Retainer key
12. Valve rod and plunger as-
sembly
13. Reaction disc
76G11X-070
14. Spring
15. Push rod
16. Front shell assembly
17. Retainer
18. Seal
19. Vacuum switch (RF, RF-CX)
11-30

POWER BRAKE UNIT 1 1
76G11X-071
Disassembly Note
Front and rear shells
1. Secure the front shell studs in a vise after attach-
ing suitable nuts to them to prevent damage to the
studs.
2. Before separating the front and rear shell assem-
blies, make matching marks to be used in reas-
sembly.
3. Fit a wrench onto the rear shell studs; then fasten
two of them with suitable nuts.
4. Rotate the rear shell counterclockwise to unlock.
Caution
The rear shell is spring loaded; loosen it
carefully.
Retainer key
Depress the plunger rod fully; then remove the re-
tainer key.
86U11X-049
86U11X-050
Assembly Note
Application of Grease
Before assembly, coat the parts shown in the figure
with silicon grease.
(1) Entire surface of reaction disc
(2) Dust seal lip
(3) Push rod
(4) Diaphragm-to-shell contacting surfaces
(5) Power piston
(6) Valve plunger oil seal
Retainer key
1. Push down the plunger rod.
2. Align the groove of the valve plunger with the slot
of the power piston.
3. Insert the retainer key.
86U11X-051
11—31

1 1 POWER BRAKE UNIT
Diaphragm
Install the diaphragm to the power piston and plate.
Caution
Check that the diaphragm is well seated in the
groove.
86U11X-052
Rear shell assembly
Assemble the rear shell assembly; carefully guiding
the tube end of the power piston through the dust
seal of the rear shell.
86U11X-053
Front shell and rear shells
Press down the rear shell assembly, and rotate it
clockwise until the matching marks are aligned.
Caution
Fit suitable nuts to two studs of the rear shell
and tighten them to mount the wrench.
76G11X-072
INSPECTION
1. Inspect all rubber parts. Wipe free of fluid and care-
fully inspect all rubber parts for cuts, nicks, and
other damage.
2. Check the power piston for cracks,distortion, chip-
ping, and damaged seats.
3. Inspect the reaction disc rubber for deterioration.
4. Check that the seats of the valve rod and plunger
are smooth and free of nicks and dents.
5. Inspect the front and rear shells for scratches,
scores, pits, dents, and other damage.
6. Check the diaphragm for cuts and other damage.
11—32

POWER BRAKE UNIT 1 1
INSTALLATION
1. Install in the reverse order of removal, referring to installation note for specially marked parts.
2. Tighten all nuts and bolts to the specified torque, referring to torque specifications.
3. After installation:
(1) Add fluid and bleed the air. (Refer to page 11—9.)
(2) Check all parts for fluid leakage.
(3) Make an on-vehicle check of the unit (Refer to page 11—27.)
(4) Verify that the vacuum hose does not contact other parts.
Torque specifications
76G11X-035
1. Vacuum hose and check valve
11—33

1 1 POWER BRAKE UNIT
Installation Note
Application of grease and sealant
1. Apply grease to the clevis pin contact surface.
2. Apply sealant to the gasket contact surface.
86U11X-057
Vacuum hose and check valve
Install the vacuum hose and check valve, noting the
installation direction.
Note (MTX)
The check valve is pressed into the vacuum
hose. There is an arrow on the hose surface
to indicate direction of installation.
76G11X-036
11—34

VACUUM PUMP 1 1
VACUUM PUMP
1. Disconnect the vacuum hose and release the re-
maining vacuum.
2. Connect a vacuum gauge as shown in the figure.
3. Run the engine at idle speed.
Idle speed: 720 1 20 rpm
4. Check that the vacuum reaches 500 mmHg (19.7
inHg) in 8 seconds or less.
5. Check that the maximum vacuum is within approx.
700—720 mmHg (27.6—28.3 inHg) in 80 sec-
onds or less.
REMOVAL AND INSTALLATION
1. Remove in the sequence shown in the figure.
2. Install in the reverse order of removal, referring to installation note for specially marked parts.
Note
The engine oil will leak out when disconnecting the oil hose. Prepare a suitable container
for it to drain into.
76G11X-038
76G11X-037
1. Vacuum hose
2. Oil return hose
3. Oil inlet hose
4. Drive velt cover
5. Vacuum pump

1 1 VACUUM PUMP
Vacuum pump
Checking
point
B -
VacuumA^^^^ pump [
(o) y
©
Rear
\ camshaft
jpulley
AHP"
76G11X-039
DISASSEMBLY AND ASSEMBLY
1. Disassemble in the sequence shown in the figure.
2. Assemble in the reverse order of disassembly.
Installation Note
Belt deflection
Inspection
Check the belt deflection within specification apply-
ing moderate pressure.
Specification
New belt: 7.5—8.5mm (0.30—0.33)
Used belt: 8.5—9.5 mm (0.33—0.37)
Adjustment
1. Loosen the mounting bolt ©and adjust bolt (§).
2. Lever the vacuum pump outward and apply ten-
sion to the belt.
3. Tighten the mounting bolt ®and adjust bolt (§)to
the specified torque. (See page 11 —35.)
18—49 N-m (2.0—5.0 m-kg, 14—36 ft-lb) ' 39—77 N-m (4.0—7.0 m-kg, 29—51 ft-lb)
29—59 N-m (3.0—6.0 m-kg, 22—43 ft-lb)
,_B.B Nm--90 cm-kg, 5.9 (60 52—78 In-lb)
2.0—4.9 N-m (20—50 cm-kg, 17—43 In-lb)
49—88 Nm (5.0-9.0 m-kg, 51—65 It-lb)
Left hand threads
1. Vacuum pump housing
2. Rotor
3. Vane
76G11X-040
4. Center plate
5. Vacuum pump bracket
assembly
6. O-ring
7. Pulley
11-36

VACUUM PUMP 1 1
INSPECTION
1. Check the rotor, housing and cover for wear or
damage.
2. Check the O-ring for deterioration or damage.
3. Check the vane for wear or damage. Replace if
necessary.
Height:
13.0—13.5 mm (0.512—0.530 in)
76G11X-041
4. Check the housing inner diameter.
Diameter:
57.0—57.1 mm (2.244—2.248 in)
76G11X-042
11-37

1
1
DUAL PROPORTIONING VALVE
B6U11X-060
DUAL PROPORTIONING VALVE
FUNCTION CHECK
1. Connect
two
pressure gauges [9,810
kPa (100

kg/cm2,1,422 psi)
]
to the brake pipes and adap-
tors
as
shown
in
the
figure.
Adaptor and flare
nut
tightening torque:
13—22 N m (1.3—2.2 m-kg, 9—16 ft-lb)
Note
Disconnect and connect the brake pipes with
the
SST
(49
0259 770B).
2. Bleed
air
from
the
brake system.
(Refer
to
page 11—9.)
76G11X-043
t 0}
^
£
»

Rear

brake
pressu
kPa
(kg/cm2,
p
>
DO

Rear

brake
pressu
kPa
(kg/cm2,
p
>
DO
TTi
A
B

Master cylinder pressure
kPa
(kg/cm2,
psi)

76G11X-044
Depress the brake pedal until the master cylinder
pressure equals A; then measure rear brake pres-
sure
A'.

Depress the brake pedal again; apply additional
pressure until
A
equals
B;
then measure pressure
B'.
If the measurements
are
not
within specification,
replace
the
valve assembly.
Install the brake pipes to the valve,
and
bleed
air

from
the
brake system.
Specification
Fluid pressure
kPa
(kg/cm2,
psi)

A A' B B'
Except General
LHD
and
RHD

1,962 (20,284)
1,962 ±
196
(20
± 2,
284
± 28)
6,867 (70,995)
3,434 ±
196
(35
± 2,
498
± 28)

General
LHD
and
RHD
2,943 (30,427)
2,943 ±
196
(30
± 2,
427
± 28)

6,867 (70,995) 4,120 ±
196
(42
± 2,
597
± 28)

11-38