housing MAZDA MIATA 1991 Factory Service Manual

ADJUSTMENTS
CLOCKSPRING CENTERING
Set front wheels in straight-ahead position. Turn clockspring connector clockwise until it stops (do not force).
Return connector 2 3/4 turns counterclockwise. Rotate clockspring connector further, if necessary, to align
marks on connector and outer housing.
DISPOSAL PROCEDURES
DEPLOYED AIR BAG
Dispose deployed air bag module as you would any other part. Wear gloves and safety glasses when handling
air bag module.
SCRAPPED VEHICLE
1. Ensure vehicle is outside, and away from other vehicles and people. Open convertible top and doors.
Disconnect negative battery cable.
2. Ensure air bag module is firmly mounted to steering wheel. Remove knee protector and disconnect
Orange and Blue clockspring connectors at base of steering column. See Fig. 1
. Cut clockspring
connector Blue wires.
3. Connect 2 jumper wires (20 feet long) to cut clockspring wires. Connect other ends of wires to a 12-volt
battery to deploy air bag. Because of heat, wait 10 MINUTES before touching deployed air bag.
REMOVAL & INSTALLATION
CRASH SENSORS NOTE: Perform the following procedures when scrapping a vehicle with undeployed air
bag.
WARNING:Follow air bag service precautions to prevent accidentalair bag
deployment and personal injury. See SERVICE PRECAUTIONS.
NOTE: After component replacement, check system to ensure proper operation. See
SYSTEM OPERATION CHECK.
NOTE: Crash sensor orientation and mounting is important for proper operation. All
sensors must be positioned so that arrow points forward. If there is sheet metal
damage near sensor mounting point, inspect body structure at sensor
mounting point for deformation. If damaged, restore to original shape. Ensure
sensor mounting bolts or nuts are tightened to specification. See TORQUE
SPECIFICATIONS table.

1991 Mazda MX-5 Miata
AIR BAG RESTRAINT SYSTEM MAZDA 1990-91 AIR BAGS
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Removal & Installation (B2200 & B2600i 2WD)
1. With caliper assembly removed, remove wheel hub grease cap, cotter pin, lock plate and ring adjusting
lock nut. Remove thrust washer and outer bearing from hub. Slide hub and rotor assembly from spindle.
2. Mark rotor-to-hub position. Separate rotor from hub. Machine rotor if lateral runout exceeds
specification. Replace rotor if measured thickness is less than specified minimum thickness. See DISC
BRAKE SPECIFICATIONS at end of article.
3. To install, reverse removal procedure and evenly tighten rotor-to-hub bolts. Adjust wheel bearings.
Removal & Installation (B2600i 4WD) 1) Remove front caliper. Set hub to FREE position. Remove hub
bolts. Remove hub as an assembly. Install 2 bolts and nuts to retain hub assembly together. Remove snap
ring and spacer.
4. Remove set bolt and plate. Remove nut. Remove rotor and hub assembly. Mark rotor-to-hub position.
Remove rotor from hub. Machine rotor if lateral runout exceeds specification. Replace rotor if measured
thickness is less than specified minimum thickness. See DISC BRAKE SPECIFICATIONS
at end of
article. To install, reverse removal procedure.
Removal & Installation (Miata, MPV, MX-6, Protege, RX7, 323 & 626)
1. Raise and support front of vehicle. Remove wheel. Remove caliper with brake hose connected. Support
caliper using rope. Remove 2 rotor-to-hub screws. Remove rotor.
2. Machine rotor if lateral runout exceeds specification. Replace rotor if measured thickness is less than
specified minimum thickness. See DISC BRAKE SPECIFICATIONS
at end of article. To install,
reverse removal procedure.
Removal & Installation (Navajo 2WD)
1. Raise vehicle, and support using safety stands. Remove wheel and caliper assemblies. Remove dust cap,
cotter pin, nut, washer and outer bearing. Carefully remove hub and rotor assembly. Remove inner
bearing and seal.
2. To install, reverse removal procedure. Adjust front wheel bearings. While rotating rotor, tighten adjusting
nut to 17-25 ft. lbs. (23-34 N.m). Back off adjusting nut 120-180 degrees. Install bearing retainer and new
cotter pin.
Removal (Navajo 4WD With Automatic Locking Hubs)
1. Raise vehicle, and support using safety stands. Remove wheel assembly and caliper. See FRONT DISC
BRAKE PADS under REMOVAL & INSTALLATION. Remove retainer washers from lug nut studs.
Remove automatic locking hub housing from spindle.
2. Remove snap ring from end of spindle shaft. Remove axle spacer. See Fig. 13
. Carefully pull plastic
moving cam off wheel bearing adjusting nut. Remove 2 plastic thrust spacers from adjusting nut. Using a
magnet, remove locking key.
CAUTION: DO NOT pry on plastic cam or spacers during removal as damage
may result. To prevent damaging spindle threads, remove locking
key before removing adjusting nut.

1991 Mazda MX-5 Miata
BRAKE SYSTEM 1991 BRAKES Mazda Brake System
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(T70T-4252-B), remove wheel bearing adjusting nut. Remove outer wheel bearing, and then remove
rotor.
Installation
When installing rotor, outer bearing and adjusting nut, tighten adjusting nut to 35 ft. lbs (47 N.m) to seat
bearings. Spin rotor, and back off adjusting nut 1/4 turn. Tighten adjusting nut to 16 INCH lbs. (1.8 N.m). To
install remaining components, reverse removal procedure. See Fig. 13
. After assembly is complete, wheel to
spindle end play should be .001-.003" (.02-.08 mm).
Removal (Navajo 4WD With Manual Locking Hubs)
1. Raise and support vehicle. Remove wheel assembly and caliper. See FRONT DISC BRAKE PADS
under REMOVAL & INSTALLATION. Remove retainer washers from lug nut studs. Remove manual
locking hub housing from spindle.
2. Remove snap ring from end of spindle shaft. Remove axle spacer. See Fig. 14
. Using Lock Nut Wrench
(T86T-1197-A), remove outer wheel bearing lock-nut. Remove lock washer. Using Lock Nut Wrench
(T86T-1197-A), remove inner wheel bearing lock nut, outer wheel bearing and rotor. CAUTION: Extreme caution must be used when aligning adjusting nut lug with
spindle locking key slot to prevent damage to locking key. Extreme
caution must be used when aligning fixed cam key with spindle key slot to
prevent damage to fixed cam.

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 DRIVE AXLES
Differentials & Drive Axles - 929, B2200, B2600i, MX-5 Miata, MPV, Protege & RX-7
AXLE RATIO & IDENTIFICATION
See AXLE RATIO SPECIFICATIONS . To determine axle ratio, divide number of ring gear teeth by number
of pinion teeth.
AXLE RATIO SPECIFICATIONS
DESCRIPTION
An optional Limited Slip Differential (LSD) is available on Miata and RX7 models. Rear drive axles are
retained in the housing by tapered bearings and bearing retainers at axle housing outer ends on B2200 and
B2600i. Rear drive axle bearings on MPV 4WD are held in place by a pressed-on collar.
On front axle on B2600i (4WD) and MPV 4WD, and rear axle on Miata, Protege 4WD, RX7 and 929, drive
axles use CV joints to connect differentials to drive hubs.
LUBRICATION
CAPACITY
Application
No. of Teeth
Pinion/Ring Gear
Ratio
B220011/433.91:1
B2600i
Front & Rear11/413.73:1
MiataN/A4.30:1
MPV (Front & Rear)
A/T10/414.01:1
M/T11/433.91:1
Protege & 929N/AN/A
RX7
A/T (1) 11/433.9:1 or 4.1:1
M/T Non-TurboN/A4.1:1 or 4.3:1
M/T TurboN/A4.1:1
(1)Non-Turbo convertible only.
NOTE: For models with independent suspension, see REAR AXLE SHAFTS (vehicles
that are normally only FWD), or AXLE SHAFTS
- FRONT article in this section
for axle shaft overhaul.

1991 Mazda MX-5 Miata
1990-91 DRIVE AXLES Differentials & Drive Axles - 929, B2200, B2600i, MX-5 Miata, MPV, Protege & RX-7

1991 Mazda MX-5 Miata
1990-91 DRIVE AXLES Differentials & Drive Axles - 929, B2200, B2600i, MX-5 Miata, MPV, Protege & RX-7
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3. Using Bearing Nut Wrench (49 0603 635A ) and Shaft Holder (49 S120 645A ), remove bearing lock nut
from axle shaft. Remove bearing and bearing retainer from axle using Puller (49 S120 520A ). Remove
outer race from hub.
END PLAY SPECIFICATIONS
(1)
Installation
1. Press new oil seal and bearing outer race into bearing retainer. Coat bearing race and outer seal with
grease. Tap inner oil seal flush with end of axle housing. Coat inner seal lip with grease.
2. Position brake backing plate onto axle shaft. Install spacer against backing plate with chamfer facing
backing plate. Using Press Attachment (49 S120 748 ) and a press, install wheel bearing onto axle shaft.
Standard press force is 4.6-6.7 tons (4200-6100 kg). If press fit force is too high or too low, replace the
bearing collar or shaft.
3. Using Bearing Nut Wrench (49 0603 635A ), install bearing lock nut to axle shaft and tighten to 145-217
ft. lbs. (196-245 N.m). Bend tab up into groove. Install one axle shaft into axle housing. Tighten backing
plate nuts to specification. Install dial indicator on backing plate and check drive axle end play.
4. To adjust end play, remove axle and insert appropriate size adjustment shim between axle hub and
housing. End play for second drive axle installed should be set to normal end play clearance of .002-
.010" (.05-.25 mm), with both axles installed.
5. Install parking brake cable, attaching pin and brake line. Install brake shoes and actuating hardware.
Bleed brake system. Install wheel and tire.
BEARING RETAINER SHIMS (B2200 & B2600i)
MPV 4WD
NOTE: On B2200 and B2600i, left axle bearing lock nut has left-hand threads.
ApplicationIn. (mm)
B2200 & B2600i
One Axle Installed.026-.037 (.65-.95)
Both Axles Installed.002-.010 (.05-.25)
(1)Check at axle flange with dial indicator.
NOTE: Ensure end play for first drive axle is within specification before inserting
second drive axle. Use shims to adjust end play if necessary.
Part NumberThickness In. (mm)
083 26 165.004 (.10)
083 26 166.006 (.15)
083 26 167.020 (.50)
083 26 168.030 (.75)

1991 Mazda MX-5 Miata
1990-91 DRIVE AXLES Differentials & Drive Axles - 929, B2200, B2600i, MX-5 Miata, MPV, Protege & RX-7
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1. Raise and support vehicle. Remove rear wheels. Remove brake drum and shoes. Using a dial indicator,
measure axle flange lateral movement. Replace bearing if play exceeds If bearing play exceeds .023" (.57
mm). Disconnect brake line from wheel cylinder. Plug line openings. Disconnect parking brake cable.
2. Remove backing plate retaining nuts. Remove axle shaft and backing plate as an assembly. Use puller or
slide hammer to pull axle and bearing from axle housing. With axle removed, remove retaining ring and
bearing collar. See Fig. 1
.
Fig. 1: Exploded View of Rear Drive Axle (MPV; Others Similar)

Courtesy of MAZDA MOTORS CORP.
3. To remove bearing collar, grind collar until a section of it is .020" (.5 mm) and cut through it with a
chisel. Use a puller or press to remove bearing and brake backing plate. Check axle shaft for straightness.
Maximum runout is .059" (1.5 mm).
4. Use a press to replace wheel studs (if necessary), never use a previously used wheel stud as a
replacement. Lubricate seal lips before replacement. DO NOT lubricate bearing retainer collar before
replacement. Use a press to install bearing collar. If press-fit of collar requires less than 2.7 tons (2699
kg.) replace collar or axle shaft. Reverse removal procedures to complete installation.
DIFFERENTIAL ASSEMBLY

1991 Mazda MX-5 Miata
1990-91 DRIVE AXLES Differentials & Drive Axles - 929, B2200, B2600i, MX-5 Miata, MPV, Protege & RX-7
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Removal (Front - B2600i & MPV 4WD)
1. Raise and support vehicle. Remove engine skid plate. Drain differential. On MPV 4WD, remove tie rod
end and lower arm. Remove front axle shafts. See AXLE SHAFTS
- FRONT article. Mark drive shaft
position, and remove drive shaft.
2. On B2600i, remove differential subframe mounting bolts and nuts. Remove differential, Remote Free
Wheel (RFW) and subframe assembly from vehicle. Remove RFW assembly from right side of
differential housing. Pull drive coupler from carrier. Remove differential carrier retaining bolts. Remove
differential carrier.
3. On MPV 4WD, remove differential housing mounting bolts and mount at end of Remote Free Wheel
(RFW) extension housing. Remove differential and extension housing from vehicle. Remove RFW
assembly from right side of differential housing. Pull drive coupler from carrier. Remove differential
carrier retaining bolts. Remove differential carrier.
Installation
To install, reverse removal procedure. See Fig. 2 or Fig. 3 . Apply Sealant (8527 77 739 ) to carrier mating
flange. Align marks made during removal. Refill differential with lubricant. Tighten all fasteners to
specification. See TORQUE SPECIFICATIONS
.

1991 Mazda MX-5 Miata
1990-91 DRIVE AXLES Differentials & Drive Axles - 929, B2200, B2600i, MX-5 Miata, MPV, Protege & RX-7
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B2600i and MPV, remove brake drum and drive axles. See REAR AXLE SHAFTS & BEARINGS. On
Protege 4WD, RX7 and 929, disconnect CV joint drive axles from differential assembly and wire aside.
2. On all models, mark flanges and disconnect drive shaft. Remove ABS sensor (if equipped). On RX7,
remove rear exhaust system and differential mount on left side of pinion flange. Remove hanger mounts
and allow left side to hang down. Disconnect sublinks and remove differential.
3. On Protege 4WD and 929 models, remove differential housing assembly-to-chassis mounting bolts.
Remove differential housing assembly from vehicle. On all models, remove differential carrier-to-
housing nuts. Remove differential carrier.
Installation
To install, reverse removal procedure. Apply Sealant (8527 77 739 ) to carrier mating flange. Align marks made
during removal. Refill differential with correct type and amount of lubricant. Tighten all fasteners to
specification. See TORQUE SPECIFICATIONS
.
Fig. 4: Exploded View of Differential Assembly (RX7)

Courtesy of MAZDA MOTORS CORP.
Removal (Miata)
1. Raise and support vehicle. Drain differential. Mark flanges and remove drive shaft. Note locations and
disconnect wiring harness from Power Plant Frame (PPF). See Fig. 5
.

1991 Mazda MX-5 Miata
1990-91 DRIVE AXLES Differentials & Drive Axles - 929, B2200, B2600i, MX-5 Miata, MPV, Protege & RX-7
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2. Support transmission with a jack. Remove PPF bracket from rear transmission extension housing.
Remove PPF-to-differential side bolts and pry out spacer. Remove PPF/differential mounting spacer. See
Fig. 6
. Install metric bolt (M14 X 1.5) into sleeve. See Fig. 7 .
3. Twist bolt side-to-side while pulling bolt downward. Install a metric bolt (M6 X 1) into hole in housing
block to hold sleeve and remove long bolt (M14 X 1.5). Remove short bolt (M6 X 1).
4. Remove PPF-to-transmission side bolts and remove PPF. Mark and disconnect CV joint drive axles from
differential assembly and wire aside. Remove differential carrier-to-housing nuts. Remove differential
carrier.
INSTALLATION
1. To install, reverse removal procedure. Apply Sealant (8527 77 739 ) to carrier mating flange. Align marks
made during removal and install differential carrier. Install differential. Raise transmission until engine
and transmission are level.
2. To install Power Plant Frame (PPF), position PPF in place. Install PPF/differential mounting spacer and
tighten bolts to 27-38 ft. lbs. (37-52 N.m). Install PPF-to-transmission side mounting bolts and tighten.
3. Ensure sleeve is installed into PPF housing block. Install spacer and bolts. Ensure reamer bolt is installed
into front hole and tighten. See Fig. 6
.
4. Install transmission-to-PPF bracket. Install remaining PPF bolts and tighten all bolts to specification. See
TORQUE SPECIFICATIONS
. To complete installation, reverse removal procedure.
NOTE: On Miata, front PPF-to-differential side mounting bolt is reamer bolt, which
aligns power plant frame. See Fig. 6
.

1991 Mazda MX-5 Miata
1990-91 DRIVE AXLES Differentials & Drive Axles - 929, B2200, B2600i, MX-5 Miata, MPV, Protege & RX-7
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