1991 MAZDA MIATA Valve

BRAKE SYSTEM
1991 BRAKES Mazda Brake System
DESCRIPTION & OPERATION
All models use hydraulic-operated brake system with a tandem master cylinder and a power brake unit.
BRAKE SYSTEM BLEEDING
BRAKE LINE BLEEDING SEQUENCE
ADJUSTMENTS
MASTER CYLINDER PUSH ROD (NAVAJO)
1. Remove master cylinder to gain access to push rod. To check screw adjustment, fabricate a gauge. See
Fig. 1
. NOTE: For information on anti-lock brake systems, see appropriate ANTI-LOCK BRAKE
SYSTEM article in the BRAKES Section.
NOTE: See BRAKE BLEEDING article in the BRAKES Section.
ApplicationSequence
Protege & 323RR, LR, LF, RF
RX7 (1) RR, LR, RF, LF
All OthersLongest Line First
(1)If rear caliper has not been disassembled, open upper bleed valve only.
NOTE: Push rod has an adjustment screw to maintain correct distance between
booster push rod and master cylinder piston. If push rod is adjusted too long, it
prevents master cylinder piston from completely releasing hydraulic pressure,
causing brakes to drag. If push rod is adjusted too short, it causes excessive
pedal travel and an undesirable clunk in booster area.

1991 Mazda MX-5 Miata
BRAKE SYSTEM 1991 BRAKES Mazda Brake System

1991 Mazda MX-5 Miata
BRAKE SYSTEM 1991 BRAKES Mazda Brake System
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4. On all models, measure applied pedal height. If distance is not as specified, check brake adjustment or
system for air. See BRAKE PEDAL HEIGHT SPECIFICATIONS TABLE.
BRAKE PEDAL HEIGHT SPECIFICATIONS
TESTING
POWER BRAKE UNIT
1. With engine off, depress brake pedal several times. Press and hold brake pedal and start engine. If brake
pedal moves down slightly immediately after engine starts, power brake unit is operating. If brake pedal
does not move as specified, go to next step.
2. Run engine for 1-2 minutes. Stop engine. Press brake pedal several times and note if first pedal stroke is
longer than subsequent strokes. If first pedal stroke is longer than subsequent strokes, power brake unit is
operating. If length of strokes is equal, test check valve and vacuum hose between vacuum source and
power brake unit. Repair as necessary, and go to next step.
3. Start engine. Press and hold brake pedal. Stop engine. Hold pedal down for about 30 seconds. If pedal
height remains at same height, power brake unit is operating. If pedal height recedes, test check valve and
vacuum hose between vacuum source and power brake unit. Repair as necessary.
REMOVAL & INSTALLATION
FRONT DISC BRAKE PADS
Removal & Installation (Protege & 323)
Raise and support front of vehicle. Remove wheels. Remove spring "A". See Fig. 5 . Remove spring "B".
Remove pad pins. Remove pads, shims and anti-squeak shim. Replace pad if lining thickness is less than
specified. See MINIMUM PAD LINING SPECIFICATIONS (FRONT) TABLE. To install, reverse removal
ApplicationIn. (mm)
Pedal Released
B2200 & B2600i7.1-7.3 (180-185)
Miata, MX-6, 626 & 9296.7-7.1 (171-181)
MPV7.5-7.9 (191-201)
Protege & 3237.6-7.7 (193-196)
RX77.2-7.4 (184-189)
Pedal Applied (1)
B2200 & B2600i4.1 (105)
Miata, MX-6, 626 & 9293.7 (95)
MPV5.2 (133)
Protege & 3232.8 (70)
RX73.9 (100)
(1)Minimum height.

1991 Mazda MX-5 Miata
BRAKE SYSTEM 1991 BRAKES Mazda Brake System
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S120-645A) and Wrench (49-0603-635A).
2. Using Puller (49-S120-520A) and Adapter (49-S120-523A), remove rear axle bearings. Remove oil seal
from axle housing.
Installation
1. Install oil seal in axle housing. Install bearing inner race. Install and position oil seal flush with end of
axle casing. Apply multipurpose grease to oil seal lip. Install spacer with concave side facing backing
plate.
2. Press axle bearing onto axle shaft. Using wrench, install and tighten lock nut to 145-217 ft. lbs. (197-295
N.m). Install axle shaft assembly. Install backing plate. Reconnect brake line and parking brake cable.
Install brake drum and wheel. Bleed brake system.
MASTER CYLINDER
Removal
1. Disconnect fluid level sensor coupler (if equipped). Disconnect and plug hydraulic lines at master
cylinder to prevent entry of dirt and loss of fluid.
2. Remove nuts attaching master cylinder to firewall or power brake unit. Remove master cylinder from
vehicle. On RX7, remove proportioning valve by-pass bolt.
Installation
1. Place Adjustment Gauge (49-F043-001) onto master cylinder. Turn screw on adjuster gauge until it
contacts piston. Remove adjuster gauge. Apply 19.7 in. Hg to power brake unit.
2. Invert adjuster gauge and place it on power brake unit. Adjust push rod on power brake unit until there is
no clearance between push rod and adjuster gauge screw. Install master cylinder. Bleed hydraulic system.
POWER BRAKE UNIT
Removal & Installation
1. Remove master cylinder from power brake unit. See MASTER CYLINDER under REMOVAL &
INSTALLATION . Disconnect vacuum line at power brake unit. From inside vehicle, remove cotter pin
and clevis pin. Separate push rod from brake pedal.
2. Remove power brake unit-to-firewall nuts. Remove power brake unit. See Fig. 22
To install, reverse
removal procedure. Bleed hydraulic system. NOTE: Left wheel lock nut has left-hand threads.

1991 Mazda MX-5 Miata
BRAKE SYSTEM 1991 BRAKES Mazda Brake System
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1990-91 ENGINE COOLING
Cooling System Specifications - MX-5 Miata
COOLING SYSTEM SPECIFICATIONS
COOLING SYSTEM SPECIFICATIONS
ApplicationSpecification
Coolant Replacement Interval30 Months Or 30,000 Miles
Coolant Capacity6.3 qts. (6.0L)
Pressure Cap11-15 psi (0.75-1.05 kg/cm2 )
Thermostat Open Temperature
Starts
Main Valve188-193°F (86.5-89.5°C)
Sub Valve182-188°F (83.5-86.5°C)
Fully Open212°F (100°C)
Thermostat Open Lift
Main Valve0.31" (8 mm)
Sub Valve0.06" (1.5 mm)

1991 Mazda MX-5 Miata
1990-91 ENGINE COOLING Cooling System Specifications - MX-5 Miata

1991 Mazda MX-5 Miata
1990-91 ENGINE COOLING Cooling System Specifications - MX-5 Miata
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ELECTRICAL COMPONENT LOCATOR
1991 MAZDA ELECTRICAL COMPONENTS
BUZZERS, RELAYS & TIMERS
BUZZERS, RELAYS & TIMERS LOCATION
CIRCUIT PROTECTION DEVICES
CIRCUIT PROTECTION DEVICES LOCATION
CONTROL UNITS
ComponentLocation
ABS System
Check Valve RelayOn top of ABS pump motor.
Motor RelayOn top of ABS pump motor.
Buzzer & Timer UnitOn bracket, behind left side of dash.
See Fig. 1
.
Circuit Opening RelayOn bracket, behind left side of dash.
See Fig. 1
.
Cooling Fan RelayIn engine compartment fuse/relay
block. See Fig. 1
.
Dashboard Illumination Lights RelayOn bracket, near master cylinder. See
Fig. 1
.
EFI Main RelayIn engine compartment fuse/relay
block. See Fig. 1
& Fig. 2 .
Fuel Pump RelayBehind left front kick panel.
Headlight RelayOn bracket, near master cylinder. See
Fig. 1
.
Headlight Retractor RelayOn bracket, near master cylinder. See
Fig. 1
.
Horn RelayOn bracket, behind left side of dash.
See Fig. 1
.
Ignition RelayIn engine compartment fuse/relay
block.
Turn Signal/Hazard Flasher RelayOn bracket, behind left side of dash.
See Fig. 1
.
ComponentLocation
Fuse BlockBehind left side of dash.
Fuse/Relay BlockIn right rear corner of engine compartment, near firewall.
See Fig. 2
.
Heater Blower Motor Circuit BreakerIn passenger compartment fuse block.

1991 Mazda MX-5 Miata
ELECTRICAL COMPONENT LOCATOR 1991 MAZDA ELECTRICAL COMPONENTS

1991 Mazda MX-5 Miata
ELECTRICAL COMPONENT LOCATOR 1991 MAZDA ELECTRICAL COMPONENTS
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CONTROL UNITS LOCATION
SENDING UNITS & SENSORS
SENDING UNITS & SENSORS LOCATION
MOTORS
MOTORS LOCATION
SOLENOIDS & SOLENOID VALVES
SOLENOIDS & SOLENOID VALVES LOCATION
ComponentLocation
ABS Control UnitBehind center of dash, near ECU.
Cruise Control UnitBehind left side of dash, above fuse block.
Engine Control Unit (ECU)Behind center of dash. See Fig. 2 .
Supplemental Safety Restraint (SRS)
ModuleBehind left side of dash. See Fig. 3 .
ComponentLocation
ABS Wheel SensorsOn each front & rear wheel hub
assembly.
Airflow MeterConnected to air filter housing. See Fig.
2 .
Atmospheric Pressure SensorBuilt-in ECU.
Brake Fluid Level SensorInside brake master cylinder.
Coolant Temperature SensorOn water outlet, at left rear of engine. See
Fig. 2
.
Cooling Fan ThermoswitchOn thermostat housing.
Crank Angle SensorOn right rear side of cylinder head. See
Fig. 2
.
Intake Air ThermosensorIn airflow sensor unit.
Oil Pressure SensorOn left side of engine near oil filter.
SRS Crash/Impact Sensors
FrontOn center, left and right front of
vehicle. See Fig. 3
.
CenterBehind center of dash. See Fig. 3 .
Throttle Position Sensor (TPS)Mounted on side of throttle body. See
Fig. 2
.
ComponentLocation
A/C-Heater Blower MotorBehind left side of dash.
Wiper MotorOn right side of firewall.

1991 Mazda MX-5 Miata
ELECTRICAL COMPONENT LOCATOR 1991 MAZDA ELECTRICAL COMPONENTS
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SWITCHES
SWITCHES LOCATION
MISCELLANEOUS
MISCELLANEOUS LOCATION
COMPONENT LOCATION GRAPHICS
ComponentLocation
Idle Speed Control SolenoidOn throttle body.
Purge Control Solenoid ValveOn right side of engine compartment, on shock
tower.
ComponentLocation
A/C Pressure SwitchOn high pressure refrigerant line.
Back-Up Light SwitchOn left side of transmission.
Clutch SwitchOn bracket, above clutch pedal. See Fig. 2 .
Neutral SwitchOn right rear side of transmission. See Fig. 2 .
Parking Brake SwitchOn base of parking brake lever.
Power Steering Pressure SwitchOn power steering housing assembly. See Fig. 2 .
Seat Belt Buckle SwitchOn driver's side seat belt buckle.
Stoplight SwitchOn bracket, above brake pedal. See Fig. 2 .
ComponentLocation
Diagnostic Check ConnectorOn left rear of engine compartment, near master cylinder. See Fig. 2 .
IgniterOn right rear corner of engine compartment, near fuse/relay block. See
Fig. 2
.
SRS Back-Up BatteryMounted below SRS control unit. See Fig. 3 .
NOTE: Figures may show multiple component locations. Refer to appropriate table for
proper figure references.

1991 Mazda MX-5 Miata
ELECTRICAL COMPONENT LOCATOR 1991 MAZDA ELECTRICAL COMPONENTS
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A/C-HEATER SYSTEM - MANUAL
1990-92 Manual A/C-Heater Systems
A/C SYSTEM SPECIFICATIONS
A/C SYSTEM SPECIFICATIONS
DESCRIPTION
Blower case, mounted under right end of instrument panel, contains blower motor and fresh/recirculated air
door. Evaporator case, to left of blower case, contains evaporator, evaporator thermoswitch and expansion
valve. Heater case, to left of evaporator case, contains airflow mode door and air-mix (temperature blend) door.
ELECTRICAL COMPONENT LOCATIONS
OPERATION
All air control doors are controlled manually by cable from control panel. Top lever controls the air-mix door,
center lever controls the fresh/recirculated air door and bottom lever controls the airflow mode door.
ApplicationSpecification
Compressor TypeNippondenso Rotary Vane
Compressor Belt Deflection (1) (2)
New5/16-23/64" (8-9 mm)
Used23/64-25/64" (9-10 mm)
Compressor Oil Capacity2.7-3.3 oz.
Refrigerant (R-12) Capacity28 oz.
System Operating Pressures
High Side171-235 psi (12.0-16.5
kg/cm
2 )
Low Side21-43 psi (1.5-3.0 kg/cm2 )
(1)With 22 lbs. (10 kg) pressure applied to center of belt.
(2)On vehicles with P/S, measure midway between crankshaft pulley and P/S pump pulley. On vehicles
without P/S, measure midway between crankshaft pulley and A/C idler pulley.
ComponentLocation
A/C RelayIn Right Front Corner Of Engine Compartment
Blower Motor RelayIn Left Rear Corner Of Engine Compartment
Blower ResistorOn Bottom Of Blower Case
Evaporator Thermoswitch. On Left Side Of Evaporator Case
Pressure SwitchIn High-Pressure Line, Between Receiver-Drier
And Evaporator

1991 Mazda MX-5 Miata
A/C-HEATER SYSTEM - MANUAL 1990-92 Manual A/C-Heater Systems

1991 Mazda MX-5 Miata
A/C-HEATER SYSTEM - MANUAL 1990-92 Manual A/C-Heater Systems
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