Valve MAZDA MIATA 1991 Factory User Guide

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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STEERING GEAR - POWER RACK & PINION
1991 STEERING Mazda - Power Rack & Pinion
DESCRIPTION
Steering system is a power-assisted rack and pinion. The system consists of a rack and pinion steering gear and
power-assist pump/reservoir. The steering gear and pump/reservoir are connected by flexible hoses.
TESTING
HYDRAULIC SYSTEM PRESSURE TEST
Pump Fluid Pressure Test
1. Disconnect pressure hose and connect pressure gauge/valve between steering pump and steering gear. See
Fig. 1
. Bleed air from system.
2. Open valve fully. Start engine and idle. Turn steering wheel lock-to-lock to increase fluid temperature to
122-140°F (50-60°C). To measure pump fluid pressure, close gauge valve completely.
3. Increase engine speed to 1000-1500 RPM. Ensure pump pressure is within specification. See
HYDRAULIC SYSTEM FLUID PRESSURE SPECIFICATIONS
table. If pressure is not within
specification, replace pump.
CAUTION: DO NOT leave gauge valve closed for more than 15 seconds, or pump may
be damaged.

1991 Mazda MX-5 Miata
STEERING GEAR - POWER RACK & PINION 1991 STEERING Mazda - Power Rack & Pinion

1991 Mazda MX-5 Miata
STEERING GEAR - POWER RACK & PINION 1991 STEERING Mazda - Power Rack & Pinion
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Fig. 1: Connecting Pressure Gauge (Except 4-Wheel Steering)
Courtesy of MAZDA MOTORS CORP.
Gear Fluid Pressure Test
1. Ensure pump pressure is within specification. To measure steering gear fluid pressure, open gauge/valve
completely. Increase engine speed to 1000-1500 RPM.
2. Turn steering wheel from lock-to-lock. Gauge pressure must be within specification. See HYDRAULIC
SYSTEM FLUID PRESSURE SPECIFICATIONStable. If pressure is less than specification, steering
gear is defective.
HYDRAULIC SYSTEM FLUID PRESSURE SPECIFICATIONS
(1)
Applicationpsi (kg/cm2 )
Miata1109-1209 (78-85)
MPV, MX-6, 626 & 9291067-1138 (75-80)
Protege
2WD1067 (75)
4WD1138 (80)
RX71138-1209 (80-85)
3231067 (75)

1991 Mazda MX-5 Miata
STEERING GEAR - POWER RACK & PINION 1991 STEERING Mazda - Power Rack & Pinion
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3. Remove pressure and return hose connections from steering gear. Remove mud flap on driver's side.
Remove steering gear mounting bolts. Remove steering gear through wheelwell on driver's side.
4. To install, reverse removal procedure. Fill and bleed system. Tighten bolts to specification. See
TORQUE SPECIFICATIONS
table.
Removal & Installation (Protege & 323)
1. Disconnect negative battery cable. Raise and support front of vehicle. Remove front wheels. Remove
engine undercover. Remove cotter pins and castle nuts from tie rod ends.
2. Using puller, remove tie rods from steering knuckles. Remove steering column intermediate shaft-to-
steering gear pinion shaft bolt. Remove pressure and return hose connections from steering gear box.
3. Remove all accessible steering gear mounting bracket upper nuts and lower bolts. On Protege, support
drive train from above. Loosen stabilizer bar left mounting bracket and remove engine mount
crossmember.
4. Remove transmission control cable clip. Remove transfer case mount nuts. Lower engine gradually until
rear engine mount bolts can be removed. Remove lower left steering gear mounting bolt from between
transaxle and transfer case.
5. On all models, remove steering gear. To install, reverse removal procedure. Fill and bleed system.
Tighten bolts to specification. See TORQUE SPECIFICATIONS
table.
Removal & Installation (RX7)
1. Remove battery. Drain cooling system. Remove fan shroud and radiator. Raise and support front of
vehicle. Remove front wheels and engine undercover.
2. Remove control links and stabilizer bar. Remove cotter pins and castle nuts from tie rod ends. Remove tie
rods from steering knuckles with puller.
3. Remove steering column intermediate shaft-to-steering gear pinion shaft bolt. Remove pressure and
return hose connections from steering gear box.
4. Remove steering gear mounting bolts. Lower steering gear brackets, steering gear and linkage from
vehicle as an assembly.
5. To install, reverse removal procedure. Fill and bleed system. Tighten bolts to specification. See
TORQUE SPECIFICATIONS
table.
Removal & Installation (929)
1. Disconnect negative battery cable. Raise and support front of vehicle. Remove front wheels. Remove
engine undercover. Disconnect pressure and return hose connections in front of steering gear.
2. Drain fluid. Disconnect return hose fitting to control valve. Remove starter for access to control valve.
Disconnect control valve and pressure switch connectors. Remove control valve. Remove cotter pins and
castle nuts from tie rod ends.
3. Using puller, remove tie rods from steering knuckles. Remove steering column intermediate shaft-to-
steering gear pinion shaft bolt. Remove steering gear mounting bolts. Remove steering gear from bottom
of vehicle.
4. To install, reverse removal procedure. Tighten bolts to specification. See TORQUE SPECIFICATIONS

1991 Mazda MX-5 Miata
STEERING GEAR - POWER RACK & PINION 1991 STEERING Mazda - Power Rack & Pinion
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Stabilizer Link Bolt/Nut12-17 (16-23)
Steering Angle Transfer Shaft-To-Steering Gear Bolt13-19 (18-26)
Steering Bracket-To-Frame Mounting Bolt46-69 (63-93)
Steering Gear Mounting Bolt
Miata34-43 (46-58)
MPV55-69 (74-93)
MX-6 & 62627-40 (36-54)
Protege, RX7, 323 & 92923-34 (31-46)
Steering Rack-To-Tie Rod
Miata58-72 (78-98)
MPV, MX-6, RX7 & 62687 (118)
Protege, 323 & 92943-58 (60-78)
Tie Rod Castle Nuts
All Models Except MPV21-32 (29-44)
MPV44-58 (59-78)
Valve Housing Bolt (929)14-22 (20-29)

1991 Mazda MX-5 Miata
STEERING GEAR - POWER RACK & PINION 1991 STEERING Mazda - Power Rack & Pinion
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