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INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . 140
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . 150DIFFERENTIAL
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . 141
REAR AXLE - 11 1/2 AA DESCRIPTION
The axle consists of a cast iron center casting dif- ferential housing with axle shaft tubes extending from each side. The tubes are pressed into the differ- ential housing and welded. The design has the cen- terline of the pinion set below the centerline of the ring gear. The axle is a full floating axle where the loads are supported by the axle housing tubes. The axle has a vent used to relieve internal pressure caused by lubricant vaporization and internal expan- sion.
OPERATION
The axle receives power from the propeller shaft. The propeller shaft is connected to the pinion gear which rotates the differential through the gear mesh with the ring gear bolted to the differential case. The engine power is transmitted to the axle shafts through the pinion mate and side gears. The side gears are splined to the axle shafts.
DIAGNOSIS AND TESTING
GEAR NOISE
Axle gear noise can be caused by insufficient lubri- cant, incorrect backlash, incorrect pinion depth, tooth contact, worn/damaged gears, or the carrier housing not having the proper offset and squareness.
Gear noise usually happens at a specific speed range. The noise can also occur during a specific type of driving condition. These conditions are accelera- tion, deceleration, coast, or constant load.
When road testing, first warm-up the axle fluid by driving the vehicle at least 5 miles and then acceler- ate the vehicle to the speed range where the noise is the greatest. Shift out-of-gear and coast through the peak-noise range. If the noise stops or changes greatly:
† Check for insufficient lubricant. † Incorrect ring gear backlash. † Gear damage. Differential side gears and pinions can be checked by turning the vehicle. They usually do not cause noise during straight-ahead driving when the gears are unloaded. The side gears are loaded during vehi- cle turns. A worn pinion shaft can also cause a snap- ping or a knocking noise.
REAR AXLE - 11 1/2 AA
3 - 128
REAR AXLE - 11 1/2 AA (Continued) BEARING NOISEThe axle shaft, differential and pinion bearings can all produce noise when worn or damaged. Bearing noise can be either a whining, or a growling sound. Pinion bearings have a constant-pitch noise. This noise changes only with vehicle speed. Pinion bearing noise will be higher pitched because it rotates at a faster rate. Drive the vehicle and load the differen- tial. If bearing noise occurs, the rear pinion bearing is the source of the noise. If the bearing noise is heard during a coast, the front pinion bearing is the source.
Worn or damaged differential bearings usually pro- duce a low pitch noise. Differential bearing noise is similar to pinion bearing noise. The pitch of differen- tial bearing noise is also constant and varies only with vehicle speed.
Axle shaft bearings produce noise and vibration when worn or damaged. The noise generally changes when the bearings are loaded. Road test the vehicle. Turn the vehicle sharply to the left and to the right. This will load the bearings and change the noise level. Where axle bearing damage is slight, the noise is usually not noticeable at speeds above 30 mph.
LOW SPEED KNOCK
Low speed knock is generally caused by a worn U-joint or by worn side–gear thrust washers. A worn pinion shaft bore will also cause low speed knock.
VIBRATION
caused by a:
Vibration at the rear of the vehicle is usually † Damaged drive shaft. † Missing drive shaft balance weight(s).
DR
† Worn or out-of-balance wheels. † Loose wheel lug nuts. † Worn U-joint(s). † Loose/broken springs. † Damaged axle shaft bearing(s). † Loose pinion gear nut. † Excessive pinion yoke run out. † Bent axle shaft(s). Check for loose or damaged front-end components or engine/transmission mounts. These components can contribute to what appears to be a rearend vibra- tion. Do not overlook engine accessories, brackets and drive belts.
NOTE: All driveline components should be exam- ined before starting any repair.
DRIVELINE SNAP
A snap or clunk noise when the vehicle is shifted into gear (or the clutch engaged), can be caused by: † High engine idle speed. † Transmission shift operation. † Loose engine/transmission/transfer case mounts. † Worn U-joints. † Loose spring mounts. † Loose pinion gear nut and yoke. † Excessive ring gear backlash. † Excessive side gear to case clearance. The source of a snap or a clunk noise can be deter- mined with the assistance of a helper. Raise the vehi- cle on a hoist with the wheels free to rotate. Instruct the helper to shift the transmission into gear. Listen for the noise, a mechanics stethoscope is helpful in isolating the source of a noise.
DIAGNOSTIC CHART
Condition
Possible Causes
Correction
Wheel Noise
1. Wheel loose.
1. Tighten loose nuts.
2. Faulty, brinelled wheel bearing.
2. Replace bearing.
Axle Shaft Noise
1. Misaligned axle tube.
1. Inspect axle tube alignment. Correct as necessary.
2. Bent or sprung axle shaft.
2. Inspect and correct as necessary.
DR REAR AXLE - 11 1/2 AA (Continued)
REAR AXLE - 11 1/2 AA
3 - 129
Condition
Possible Causes
Correction
Axle Shaft Broke
1. Misaligned axle tube.
2 Vehicle overloaded.
3. Erratic clutch operation.
4. Grabbing clutch.
Differential Cracked
1. Improper adjustment of the differential bearings.
2. Excessive ring gear backlash.
3. Vehicle overloaded.
4. Erratic clutch operation.
Differential Gears Scored
1. Insufficient lubrication.
2. Improper grade of lubricant.
3. Excessive spinning of one wheel/tire.
Loss Of Lubricant
1. Lubricant level too high.
2. Worn axle shaft seals. 3. Cracked differential housing. 4. Worn pinion seal. 5. Worn/scored yoke. 6. Axle cover not properly sealed.
1. Replace the broken shaft after correcting tube mis-alignment.
2. Replace broken shaft and avoid excessive weight on vehicle. 3. Replace broken shaft and avoid or correct erratic clutch operation. 4. Replace broken shaft and inspect and repair clutch as necessary.
1. Replace case and inspect gears and bearings for further damage. Set differential bearing pre-load properly.
2. Replace case and inspect gears and bearings for further damage. Set ring gear backlash properly. 3. Replace case and inspect gears and bearings for further damage. Avoid excessive vehicle weight. 4. Replace case and inspect gears and bearings for further damage. Avoid erratic use of clutch.
1. Replace scored gears. Fill differential with the correct fluid type and quantity.
2. Replace scored gears. Fill differential with the correct fluid type and quantity. 3. Replace scored gears. Inspect all gears, pinion bores, and shaft for damage. Service as necessary.
1. Drain lubricant to the correct level.
2. Replace seals. 3. Repair as necessary. 4. Replace seal. 5. Replace yoke and seal. 6. Remove, clean, and re-seal cover.
Axle Overheating
1. Lubricant level low.
1. Fill differential to correct level.
2. Improper grade of lubricant.
3. Bearing pre-loads too high. 4. Insufficient ring gear backlash.
2. Fill differential with the correct fluid type and quantity. 3. Re-adjust bearing pre-loads. 4. Re-adjust ring gear backlash.
REAR AXLE - 11 1/2 AA
3 - 130
REAR AXLE - 11 1/2 AA (Continued)DR
Condition
Possible Causes
Correction
Gear Teeth Broke
1. Overloading.
2. Erratic clutch operation.
3. Ice-spotted pavement.
4. Improper adjustments.
Axle Noise
1. Insufficient lubricant.
2. Improper ring gear and pinion adjustment.
3. Unmatched ring gear and pinion.
4. Worn teeth on ring gear and/or pinion. 5. Loose pinion bearings. 6. Loose differential bearings.
7. Mis-aligned or sprung ring gear.
8. Loose differential bearing cap bolts.
9. Housing not machined properly.
REMOVAL
INSTALLATION
1. Replace gears. Examine other gears and bearings for possible damage.
2. Replace gears and examine the remaining parts for damage. Avoid erratic clutch operation. 3. Replace gears and examine remaining parts for damage. 4. Replace gears and examine remaining parts for damage. Ensure ring gear backlash is correct.
1. Fill differential with the correct fluid type and quantity. 2. Check ring gear and pinion contact pattern. Adjust backlash or pinion depth. 3. Replace gears with a matched ring gear and pinion. 4. Replace ring gear and pinion.
5. Adjust pinion bearing pre-load. 6. Adjust differential bearing pre-load. 7. Measure ring gear run-out. Replace components as necessary. 8. Inspect differential components and replace as necessary. Ensure that the bearing caps are torqued tot he proper specification. 9. Replace housing.
(1) Raise and support the vehicle. (2) Position a lifting device under the axle. (3) Secure axle to device. (4) Remove wheels and tires assemblies. (5) Remove RWAL sensor from the differential
(1) Raise axle with lifting device and align to the
leaf spring centering bolts.
(2) Install axle U-bolts and tighten to 149 N·m
(3) Install shock absorbers to axle and tighten to
housing.
brackets.
and axle vent hose.
(6) Remove brake hose at the axle junction block
(4) Install the RWAL sensor to the differential
(7) Disconnect parking brake cables and cable
(5) Connect the parking brake cables and cable
(8) Remove brake calipers. (9) Mark propeller shaft and companion flange for
and axle vent hose.
(6) Connect brake hose to the axle junction block
installation alignment reference.
(10) Remove propeller shaft. (11) Remove shock absorbers from axle. (12) Remove U-bolets from axle. (13) Separate the axle from the vehicle.
(7) Align propeller shaft and pinion companion flange reference marks and tighten companion flange bolts to 115 N·m (85 ft. lbs.).
(8) Install the wheels and tires. (9) Fill differential to specifications.
(110 ft. lbs.).
specification.
housing.
brackets.
DR REAR AXLE - 11 1/2 AA (Continued)
(10) Remove lifting device from axle and lower the
vehicle.
ADJUSTMENTS
Ring and pinion gears are supplied as matched sets only. Compensation for pinion depth variance is achieved with a select shim. The shim is located between the rear pinion bearing and the pinion gear head.
PINION DEPTH MEASUREMENT AND ADJUSTMENT Measurements are taken with pinion bearing cups and pinion bearings installed in the housing. Take measurements with Pinion Gauge Set and Dial Indi- cator C-3339 (Fig. 1).
Fig.1PINIONGEARDEPTHGAUGETOOLS
1 - DIAL INDICATOR 2 - ARBOR 3 - PINION HEIGHT BLOCK 4 - CONE 5 - SCREW 6 - PINION BLOCK 7 - SCOOTER BLOCK 8 - ARBOR DISC
(1) Assemble Pinion Height Block 6739, Pinion Block 8897 and rear pinion bearing onto Screw 6741
(Fig. 1).(2) Insert assembled height gauge components, rear bearing and screw into the housing through pin- ion bearing cups (Fig. 2).
(3) Install
front pinion bearing and install the Cone-nut 6740 hand tight. Then check tool rotating torque with an inch pound torque wrench. The rotat- ing torque should be 1.7-2.26 N·m (15-20 in. lbs.). (Fig. 1).
REAR AXLE - 11 1/2 AA
3 - 131
Fig.2PINIONHEIGHTBLOCK
1 - PINION BLOCK 2 - PINION HEIGHT BLOCK
(4) Place Arbor Discs 8289 on Arbor D-115-3 in position in the housing side bearing cradles (Fig. 3). (5) Install differential bearing caps on arbor discs and snug the bearing cap bolts. Then cross tighten cap bolts to 281 N·m (207 ft. lbs.).
NOTE: Arbor should rotate freely in the arbor discs.
Fig.3GAUGETOOLSINHOUSING
1 - ARBOR DISC 2 - PINION BLOCK 3 - ARBOR 4 - PINION HEIGHT BLOCK
(6) Assemble Dial Indicator C-3339 into Scooter
Block D-115-2 and secure set screw.
(7) Position Scooter Block/Dial Indicator flush on the pinion height block. Hold scooter block and zero the dial indicator.
REAR AXLE - 11 1/2 AA
3 - 132
REAR AXLE - 11 1/2 AA (Continued)DR
(8) Slowly slide the scooter block across the pinion height block over to the arbor (Fig. 4). Move the scooter block till dial indicator crests the arbor, then record the highest reading.
(9) Select a shim equal to the dial indicator read-
ing.
(10) Install the select shim between the rear pin-
ion bearing and the pinion gear head.
Fig.4PINIONGEARDEPTHMEASUREMENT
1 - ARBOR 2 - SCOOTER BLOCK 3 - DIAL INDICATOR
DIFFERENTIAL CASE BEARING PRELOAD AND GEAR BACKLASH
Fig.5ADJUSTERLOCKBOLT
1 - DIFFERENTIAL CASE 2 - ADJUSTER LOCK 3 - ADJUSTER LOCK BOLT 4 - BEARING CAP BOLT
Backlash is adjusted by moving the adjusters in and out or both. By moving the adjusters the case/ ring gear will move closer or further away from the pinion. In most cases this adjustment can be used to achieve the correct gear tooth pattern and set the case bearing preload.
(1) Remove adjuster lock bolts and adjuster locks
(Fig. 5).
(2) Loosen the differential bearing caps. (3) Slide differential case toward the pinion gear until the gears make contact/zero backlash. If zero backlash cannot be obtained, turn the pinion side adjuster until zero backlash is obtained.
(4) Holding the differential case toward the pinion gear, turn bearing adjusters with Spanner Wrench 8883 (Fig. 6) until they make contact with the differ- ential bearings/cups.
(5) Back off the ring gear side adjuster 4 holes, to
obtain initial ring gear backlash.
(6) Install ring gear side adjuster lock and bolt. Do
not tighten adjuster lock bolt at this time.
(7) Tighten pinion gear
side adjuster
firmly
against the differential case bearing cup.
(8) Rotate the pinion several times to seat the def-
erential bearings.
Fig.6ADJUSTERSPANNERWRENCH
1 - WRENCH 2 - DIFFERENTIAL
(9) Loosen pinion gear side adjuster until it is no longer in contact with the bearing cup, then tighten it until it makes contact. (10) Tighten pinion gear side adjuster an addi- tional:† New Bearings: 6 Adjuster Holes † Original Bearings: 4 Adjuster Holes (11) Install pinion gear side adjuster lock and bolt.
Do not tighten adjuster lock bolt at this time.
REAR AXLE - 11 1/2 AA
3 - 133
† Gear contact pattern correct (Fig. 8). Backlash
and pinion depth is correct.
DR REAR AXLE - 11 1/2 AA (Continued)
(12) Tighten bearing cap bolts to 115 N·m (85 ft.
(13) Tighten adjuster lock bolts to 33 N·m (24 ft.
lbs.).
lbs.).
(14) Measure ring gear backlash with a Dial Indi- cator C-3339 and Dial Indicator Stud L-4438 at eight points around the drive side of the ring gear (Fig. 7). The backlash should be 0.08-0.25 mm (0.003-0.010
in) with a preferred backlash of 0.13-0.18 mm (0.005- 0.007 in).NOTE: Backlash measurement should not vary more than 0.05 mm (0.002 in) between measuring points. If measurement does vary inspect the gears for burrs, the differential case flange and ring gear mounting.
Fig.8CORRECTCONTACTPATTERN
† Ring gear too far away from pinion gear (Fig. 9). Decrease backlash, by moving the ring closer to the pinion gear using the adjusters.
Fig.7RINGGEARBACKLASH
1 - COAST SIDE TOE 2 - DRIVE SIDE HEEL
Fig.9INCORRECTBACKLASH
1 - DIAL INDICATOR 2 - RING GEAR
GEAR TOOTH CONTACT PATTERN
Gear tooth contact pattern is used to verify the cor- rect running position of the ring and pinion gears. This will produce low noise and long gear life. Gears which are not positioned properly may be noisy and have shorten gear life.
(1) Wipe clean each tooth of the ring gear. (2) Apply gear marking compound to all of the ring
gear teeth.
tion.
(3) Verify bearing cap bolts are torque specifica-
(4) Apply parking brakes lightly to create at 14
N·m (10 ft. lbs.) pinion rotating torque.
(5) Rotate the pinion/pinion yoke 4 full revolutions
in each directions.
(6) Read gear tooth contact pattern:
† Ring gear too close to pinion gear (Fig. 10). Increase backlash, by moving the ring away from the pinion gear using the adjusters.
Fig.10INCORRECTBACKLASH
1 - DRIVE SIDE TOE 2 - COAST SIDE HEEL
REAR AXLE - 11 1/2 AA
3 - 134
REAR AXLE - 11 1/2 AA (Continued) † Ring gear too far away from pinion gear (Fig. 11). Decrease backlash, by moving the ring closer to the pinion gear using the adjusters.DR
† Pinion gear is set too low (Fig. 13). Increase pin- ion gear height, by increasing the pinion depth shim thickness.
Fig.11INCORRECTBACKLASH
1 - DRIVE SIDE HEEL 2 - COAST SIDE HEEL
† Ring gear too close to pinion gear (Fig. 12). Increase backlash, by moving the ring away from the pinion gear using the adjusters.
Fig.13LOWPINIONHEIGHT
† Pinion gear is set too high (Fig. 14). Decrease pinion depth, by decreasing the pinion depth shim thickness.
Fig.12INCORRECTBACKLASH
1 - DRIVE SIDE TOE 2 - COAST SIDE TOE
Fig.14HIGHPINIONHEIGHT
DR REAR AXLE - 11 1/2 AA (Continued) SPECIFICATIONS
REAR AXLE - 11 1/2 AA
3 - 135
AXLE SPECIFICATIONS
DESCRIPTION
Axle Ratio
Ring Gear Diameter Ring Gear Backlash
Pinion Bearing Preload - New Bearings
Pinion Bearing Preload - Original Bearings
Pinion Bearing Preload + Differential Case Bearing
Preload - New Bearing
Pinion Bearing Preload + Differential Case Bearing
Preload - Original Bearing
SPECIFICATION
3.73, 4.10
292 mm (11.5 in.)
0.13-0.18 mm (0.005-0.007 in.) 1.69-2.82 N·m (15-25 in. lbs.)
1-2 N·m (10-20 in. lbs.)
3.4-5.6 N·m (30-50 in. lbs.)
2.8-5.1 N·m (25-45 in. lbs.)
TORQUE SPECIFICATIONS
DESCRIPTION Fill Hole Plug
Differential Cover Bolts
Bearing Cap Bolts Ring Gear Bolts Axle Flange Bolts Adjuster Lock Bolt
SPECIAL TOOLS
N·m 32
40
281
237
129
25Ft. Lbs.
In. Lbs.
24
30
207
175
95
18DIALINDICATORSETC-3339
PINIONDEPTHGAUGE6730
DIALINDICATORSTUDL-4438
ARBORDISCS8289
REAR AXLE - 11 1/2 AA
3 - 136
REAR AXLE - 11 1/2 AA (Continued)DR
ADJUSTERWRENCH8883
PINIONDRIVER8977
PINIONBLOCK8897
PINIONINSTALLER8981
FLANGEPULLER8992
SOCKET8954
FLANGEWRENCH8979
BEARINGINSTALLER8965
DR REAR AXLE - 11 1/2 AA (Continued)
REAR AXLE - 11 1/2 AA
3 - 137
BEARINGINSTALLERD-389
CUPINSTALLER8968
CUPINSTALLER8153
SEALINSTALLER8896
CUPINSTALLER8960
SEALINSTALLER8963
CUPINSTALLER8961
REAR AXLE - 11 1/2 AA
3 - 138
REAR AXLE - 11 1/2 AA (Continued)DR
AXLE SHAFTS REMOVAL
(1) Remove axle shaft flange bolts (Fig. 15).
PLUG8964
SPLITTER1130
BRIDGE938
HANDLEC-4171
Fig.15AXLEFLANGEBOLTS
1 - AXLE FLANGE 2 - FLANGE BOLT
(2) Slide axle shaft out of the axle tube. (3) Remove axle shaft gasket.
INSTALLATION
NOTE: Axle flange bolts must be replaced or use Mopar Lock N’ Seal or LoctiteT 242 on cleaned existing bolts.
(1) Clean axle flange and hub. (2) Install new axle shaft gasket. (3) Slide axle shaft into the axle tube. (4) Install axle shaft flange bolts and tighten to
129 N·m ( 95 ft. lbs.).
AXLE BEARINGS REMOVAL
(1) Remove axle shaft flange bolts and remove
shaft.
shaft tube.
hub.
(2) Remove retianer ring (Fig. 16) from the axle
(3) Remove hub bearing nut locking key (Fig. 17). (4) Remove hub bearing nut with Socket 8954. (5) Remove hub and bearings from the axle. (6) Pry out hub bearing seal from the back of the
DR AXLE BEARINGS (Continued)
REAR AXLE - 11 1/2 AA
3 - 139
Fig.16RETAINERRING
1 - RETAINER RING 2 - LOCKING KEY 3 - BEARING NUT
Fig.18INNERPARTOFSEAL
1 - PRY BAR 2 - AXLE TUBE 3 - REMAINING SEAL
INSTALLATION
(1) Install outer hub bearing cup with Installer
8961 and Handle C-4171.
8153 and Handle C-4171.
(2) Install
inner hub bearing cup with Installer
(3) Pack bearings with the appropriate wheel bear-
ing grease.
(4) Install rear bearing and install new grease
seal with Installer 8963 and Handle C-4171.
(5) Slide hub on the axle tube and install front
bearing into the hub.
(6) Install hub bearing nut with Socket 8954 and tighten to 30 N·m (22 ft. lbs.) while rotating the hub (Fig. 19).
Fig.17LOCKINGKEY
1 - BEARING NUT 2 - LOCKING KEY 3 - AXLE TUBE
NOTE: The inner part of the seal may stay on the axle tube (Fig. 18). This part must also be removed.
(7) Remove rear bearing. (8) Remove hub bearing cups with a hammer and
drift.
Fig.19HUBNUTSOCKET
1 - SOCKET 2 - TORQUE WRENCH
3 - 140
REAR AXLE - 11 1/2 AA AXLE BEARINGS (Continued)(7) Back off nut about 30° and align next hub nut key slot with axle tube key slot and install locking key.
NOTE: End play (0.01-0.001 in.)
should be
0.025-0.25 mm
DR
(8) Install retainer ring with ring end in the key
(9) Install new axle shaft gasket and install the
slot.
axle shaft.
PINION SEAL REMOVAL
(1) Remove axle shafts. (2) Mark the propeller shaft and pinion flange for
installation reference.
(3) Remove propeller shaft. (4) Rotate pinion gear three or four times. (5) Measure and record the amount of torque nec- essary to rotate the pinion gear with an inch pound torque wrench (Fig. 20).
Fig.20PINIONROTATINGTORQUE
1 - PINION FLANGE 2 - TORQUE WRENCH
(6) Hold pinion flange with Flange Wrench 8979
(Fig. 21) and remove pinion flange nut.
(7) Remove pinion flange with Pinion Flange
Puller 8992 (Fig. 22).
(8) Remove pinion shaft seal with a pry tool or
slide hammer mounted screw.
Fig.21FLANGEWRENCH
1 - PINION FLANGE 2 - FLANGE WRENCH
Fig.22PINIONFLANGEPULLER
1 - PINION FLANGE 2 - PULLER
INSTALLATION
(Fig. 23).
ion flange splines.
(1) Install new pinion seal with Installer 8896
(2) Apply a light coat of teflon sealant to the pin-
(3) Lightly tap the pinion flange onto the pinion
until a few threads are showing.
(4) Install flange washer and new pinion nut. (5) Hold pinion flange with Flange Wrench 8979
(Fig. 24) and tighten pinion nut until pinion end play is taken up.(6) Rotate pinion several times to seat bearings. (7) Measure pinion rotating torque with an inch pound torque wrench and compare it to recorded measurement. Tighten pinion nut in small incre-
DR PINION SEAL (Continued)
REAR AXLE - 11 1/2 AA
3 - 141
OPERATION
During straight-ahead driving, the differential pin- ion gears do not rotate on the pinion mate shaft. This occurs because input torque applied to the gears is divided and distributed equally between the two side gears. As a result, the pinion gears revolve with the pinion mate shaft but do not rotate around it (Fig. 25).
Fig.23PINIONSEALINSTALLER
1 - HANDLE 2 - INSTALLER
Fig.25DIFFERENTIAL-STRAIGHTAHEADDRIVING 1 - IN STRAIGHT AHEAD DRIVING EACH WHEEL ROTATES AT 100% OF CASE SPEED 2 - PINION GEAR 3 - SIDE GEAR 4 - PINION GEARS ROTATE WITH CASE
When turning corners, the outside wheel must travel a greater distance than the inside wheel to complete a turn. To accomplish this, the differential allows the axle shafts to turn at unequal speeds (Fig. 26). In this instance, the input torque applied to the pinion gears is not divided equally. The pinion gears now rotate around the pinion mate shaft in opposite directions. This allows the side gear and axle shaft attached to the outside wheel to rotate at a faster speed.
Fig.24FLANGEWRENCH
1 - FLANGE WRENCH 2 - PINION FLANGE
ments, until pinion rotating torque is 0.40-0.57 N·m (3-5 in. lbs.) greater than recorded measurement.
(8) Rotate pinion several times then verify pinion
rotating torque again.
(9) Install axle shafts. (10) Install propeller shaft with reference marks
aligned.
(11) Check differential fluid level.
DIFFERENTIAL DESCRIPTION
The differential case is a one-piece design. The dif- ferential pinion shaft is retained with a snap ring. Differential bearing preload and ring gear backlash is adjusted by the use of adjusters. The adjuster are between the differential bearings and the differential housing. Pinion bearing preload is set and main- tained by the use of a collapsible spacer. The stamped steel cover provides a means for inspection and servicing the differential.
Fig.26DIFFERENTIAL-ONTURNS
1 - PINION GEARS ROTATE ON PINION SHAFT
REAR AXLE - 11 1/2 AA
3 - 142
DIFFERENTIAL (Continued) REMOVALDR
(1) Remove fill hole plug from the differential
housing cover.
the lubricant.
(Fig. 27).
(2) Remove differential housing cover and drain
(3) Remove axle shafts. (4) Remove adjuster lock bolts and adjuster locks
Fig.28ADJUSTERS
1 - BEARING CUP 2 - ADJUSTER 3 - BEARING CUP 4 - ADJUSTER
Fig.27ADJUSTERLOCKS
1 - LOCK BOLT 2 - ADJUSTER LOCK 3 - ADJUSTER 4 - BEARING CAP
(5) Mark bearing caps left and right for installa-
(6) Remove bearing cap bolts and remove bearing
tion reference.
caps.
(7) Loosen differential bearing adjusters (Fig. 28)
with Spanner Wrench 8883.
(8) Remove differential case from the housing. (9) Remove bearing cups and tag them left and
right for installation reference.
DISASSEMBLY
(1) Remove ring gear. (2) Remove pinion shaft with a hammer and punch from the side with the hole in the pinion shaft (Fig. 29).
(3) Rotate one pinion gear with thrust washer (Fig. 30) to the differential window and remove the gear.
Fig.29PINIONSHAFT
1 - PINION GEAR 2 - PINION SHAFT 3 - EXCITER RING
DR DIFFERENTIAL (Continued)
REAR AXLE - 11 1/2 AA
3 - 143
Fig.30FIRSTPINIONGEAR
Fig.32SIDEGEARS
1 - DIFFERENTIAL WINDOW 2 - PINION GEAR 3 - THRUST WASHER
(4) Rotate the other pinion gear with thrust washer (Fig. 31) to the differential window and remove the gear.
1 - SIDE GEAR 2 - SIDE GEAR 3 - PINION GEARS
ASSEMBLY
NOTE: If the same gears and thrust washers are being used, install them into their orignial locations.
(1) Lubricate all differential components with axle
(2) Install differential side gears and thrust wash-
lubricant.
ers (Fig. 33).
Fig.31SECONDPINIONGEAR
1 - DIFFERENTIAL WINDOW 2 - THRUST WASHER 3 - PINION GEAR
(5) Remove differential side gears and thrust
washers (Fig. 32).
Fig.33SIDEGEAR
1 - DIFFERENTIAL WINDOW 2 - SIDE GEAR
REAR AXLE - 11 1/2 AA
3 - 144
DIFFERENTIAL (Continued)(3) Install first pinion gear into the differential window and side gears. Rotate the pinion gear to the back of the case (Fig. 34).
DR
INSTALLATION
(1) Clean the housing cavity with a flushing oil,
light engine oil or lint free cloth.
CAUTION: Do not use water, steam, kerosene or gasoline for cleaning.
(2) Lubricate differential case bearing. (3) Install differential case with bearings cups into
the housing.
NOTE: A light coat of grease on the cups will hold them in place during installation.
(4) Install bearing caps and bolts (Fig. 36). Tighten
the bearing cap bolts finger-tight.
NOTE: Do not torque bearing cap and bolts at this time.
Fig.34PINIONGEAR
1 - DIFFERENTIAL WINDOW 2 - SIDE GEARS 3 - PINION GEAR
(4) Install
the other pinion gear and thrust washer. Rotate the gears to align hole in the pinion gears with hole in the differential case.
(5) Slide pinion shaft into the case and through the pinion gears. Tap the shaft to seat the pinion shaft snap-ring into the case (Fig. 35).
Fig.36CASEBEARINGCAP
1 - DIFFERENTIAL HOUSING 2 - BEARING CAP 3 - ADJUSTER
Fig.35PINIONSHAFTINSTALLATION
1 - SNAP RING 2 - SIDE GEAR 3 - PINION GEAR 4 - PINION SHAFT
(6) Install ring gear.
(5) Slide differential case toward the pinion gear until the gears make contact/zero backlash. If zero backlash cannot be obtained, turn the pinion side adjuster until zero backlash is obtained.
(6) Holding the differential case toward the pinion gear, turn bearing adjusters with Spanner Wrench 8883 until they make contact with the differential bearings/cups.
(7) Back off the ring gear side adjuster 4 holes, to
obtain initial ring gear backlash.
DR DIFFERENTIAL (Continued)
(8) Install ring gear side adjuster lock and bolt. Do
not tighten adjuster lock bolt at this time.
(9) Tighten pinion gear
side adjuster
firmly
against the differential case bearing cup.
(10) Rotate the pinion several times to seat the dif-
ferential bearings.
(11) Loosen pinion gear side adjuster until it is no
longer in contact with the bearing cup.
(12) Tighten pinion gear side adjuster until it just
makes contact with the bearing cup. (13) Tighten pinion gear side adjuster an additional: † New Bearings 6 Adjuster Holes † Original Bearings 4 Adjuster Holes (14) Install pinion gear side adjuster lock and bolt.
Do not tighten adjuster lock bolt at this time.
(15) Tighten bearing cap bolts to 281 N·m (207 ft.
(16) Tighten adjuster lock bolts to 25 N·m (18 ft.
lbs.).
lbs.) (Fig. 37).
Fig.37ADJUSTERLOCKBOLT
1 - DIFFERENTIAL CASE 2 - ADJUSTER LOCK 3 - ADJUSTER LOCK BOLT 4 - BEARING CAP BOLT
(17) Measure ring gear backlash and check gear tooth contact pattern. Refer to Adjustments for pro- cedure.
(18) Install axle shaft gasket and install axle
(19) Install differential housing gasket and cover.
Tighten cover bolts to 40 N·m (30 ft. lbs.).
(20) Fill axle with lubricant, refer to Lubrication &
Maintenance for capacity and lubricant type.
(21) Install fill plug and tighten to 32 N·m (24 ft.
shafts.
lbs.).
REAR AXLE - 11 1/2 AA
3 - 145
DIFFERENTIAL TRAC-RITE DESCRIPTION
The Trac-Rite™ differential is a helical gear differ- ential. The differential has two side gears, six pinion gears and six pinion brake shoes.
NOTE: The differential is seviced as an assembly only if damaged, but can be disassembled for cleaning. The assembly should be cleaned every time a bearing is changed due to damage.
OPERATION
When one wheel begins to spin the pinion gears on that side are forced toward the pinion brake shoes. The pinion brake shoes then cause frictional drag on the opposite pinion gears and the side gear. These friction forces transfer the power to the opposite wheel. Once the frictional forces are overcome, differ- entiation will occur. The torque will be continually biased by the frictional forces to the high traction wheel.
DISASSEMBLY
(1) Remove differential ring gear bolts. (2) Remove differential case cover locating screws
(Fig. 38).
Fig.38LOCATIONSCREWS
1 - DIFFERENTIAL COVER 2 - LOCATION SCREWS
(3) Remove differential case cover. (4) Remove side gear and thrust washer (Fig. 39).
REAR AXLE - 11 1/2 AA
3 - 146
DIFFERENTIAL TRAC-RITE (Continued)NOTE: Mark all component locations.
DR
Fig.39SIDEGEARANDTHRUSTWASHER
1 - SIDE GEAR 2 - THRUST WASHER
(5) Remove three pinion brake shoes (Fig. 40).
Fig.40PINIONBRAKESHOES
1 - BRAKE SHOES 2 - PINION GEARS
(6) Remove six pinion gears (Fig. 41).
Fig.41PINIONGEARS
1 - PINION GEARS 2 - SIDE GEAR
(7) Remove remaining side gear thrust washer and
spacer.
(8) Remove remaining three pinion brake shoes.
CLEANING
Clean the differential case and gears with light oil
or a lint free cloth.
NOTE: Never use water, steam, kerosene or gaso- line for cleaning.
INSPECTION
NOTE: Minor corrosion, nicks or scratches can be smoothed with 400 grit emery cloth and polished out with crocus cloth.
(1) Inspect pinion gears teeth for chips and cracks
(2) Inspect pinion gears shafts and brake shoes for
scratches, flat-spots or worn (Fig. 42).
(3) Inspect side gears teeth for chips and cracks
(4) Inspect pinion and side gear bores for scratches
(Fig. 42).
(Fig. 43).
(Fig. 44).
NOTE: If any damage is found the differential must be replaced as an assembly. Individual components can not be replaced separately.
DR DIFFERENTIAL TRAC-RITE (Continued)
REAR AXLE - 11 1/2 AA
3 - 147
Fig.42PINIONGEARANDBRAKESHOE
1 - BRAKE SHOES 2 - PINION GEAR 3 - PINION SHAFT
Fig.44PINION/SIDEGEARBORE
1 - PINION BORES 2 - SIDE GEAR BORE
(3) Install side gear thrust washer, side gear and
spacer (Fig. 45).
Fig.43SIDEGEARS
1 - THRUST WASHERS 2 - SPACER 3 - SIDE GEARS
ASSEMBLY
NOTE: Install all component in their original loca- tions.
(1) Lubricate all gears and differential bores with
differential lubricant.
case bores.
(2) Install one set of pinion brake shoes into the
NOTE: Brake shoes can be installed upside down, but if install wrong pinion gear will not fit.
Fig.45SIDEGEARANDSPACER
1 - SPACER 2 - SIDE SPACER
REAR AXLE - 11 1/2 AA
3 - 148
DIFFERENTIAL TRAC-RITE (Continued)DR
(4) Install one set of pinion gears into the bores next to the brake shoes, with the pinion shaft facing up.
(5) Install other side gear and thrust washer. (6) Install other set of pinion gears into the brake
shoes in the case.
gears shafts (Fig. 46).
(7) Install other set of brake shoes onto the pinion
Fig.46PINIONBRAKESHOES
1 - BRAKE SHOES 2 - PINION GEARS
(8) Install differential cover and location screws. (9) Install new ring gear bolts and tighten to 237
N·m (175 ft. lbs.).
DIFFERENTIAL CASE BEARINGS REMOVAL
(1) Remove differential case from the housing. (2) Install Plug 8964 into the end of the case. (3) Remove differental case bearings with Bearing
Splitter 1130 and Bridge 938 (Fig. 47).
INSTALLATION
(1) Install differenial case bearings with Installer
8965 and Handle C-4171 (Fig. 48).
(2) Install differentail case into housing.
Fig.47DIFFERENTIALCASEBEARING
1 - BRIDGE 2 - SPLITTER 3 - BEARING 4 - PLUG
Fig.48DIFFERENTIALCASEBEARINGS
1 - HANDLE 2 - DIFFERENTIAL CASE 3 - BEARING 4 - INSTALLER
DR
REAR AXLE - 11 1/2 AA
3 - 149
(6) Remove bolts holding ring gear to differential
case.
(7) Drive ring gear from differential case with a
soft hammer (Fig. 50).
PINION GEAR/RING GEAR/ TONE RING REMOVAL
NOTE: The ring and pinion gears are service in a matched set. Never replace the ring gear/pinion gear without replacing the other matching gear.
(1) Mark pinion flange and propeller shaft for
installation alignment.
(2) Disconnect propeller shaft from pinion flange
and remove propeller shaft.
(3) Remove differential from the housing. (4) Place differential on Plug 8964. Drive exciter ring off the differential case with a hammer and punch (Fig. 49).
NOTE: Do not remove the exciter ring if it is not being replaced.
Fig.50RINGGEAR
1 - DIFFERENTIAL CASE 2 - RING GEAR 3 - HAMMER
(8) Hold pinion flange with Flange Wrench 8979
(Fig. 51) and remove pinion flange nut.
Fig.49EXCITERRING
1 - DIFFERENTIAL CASE 2 - RING GEAR 3 - PUNCH 4 - EXCITER RING
Fig.51FLANGEWRENCH
(5) Place differential case in a vise with soft metal
jaw protectors
1 - PINION FLANGE 2 - FLANGE WRENCH
REAR AXLE - 11 1/2 AA
3 - 150
PINION GEAR/RING GEAR/TONE RING (Continued)DR
(9) Remove pinion flange from pinion with Pinion
Flange Puller 8992 (Fig. 52).
(14) Remove rear pinion bearing with Bearing
Splitter 1130 and a press (Fig. 54).
Fig.52PINIONFLANGEPULLER
Fig.54BEARINGSPLITTER
1 - PINION FLANGE 2 - PULLER
1 - PINION BEARING 2 - SPLITTER
(15) Remove pinion depth shim from the pinion
gear shaft and record thickness of the shims.
(16) Remove front pinion bearing cup from the housing with a punch and hammer, and discard cup.
CAUTION: Do not reuse front pinion bearing/cup.
(17) Remove rear pinion bearing cup from the if bearing is
housing with a punch and hammer, going to be replaced.
INSTALLATION
(1) Install new front pinion bearing cup (Fig. 55)
with Installer 8960 and Handle C-4171.
(10) Remove pinion gear from housing with Pinion
Driver 8977 and a hammer (Fig. 53).
NOTE: Thread the driver on the pinion shaft till it bottoms out.
Fig.53PINIONDRIVER
1 - PINION SHAFT 2 - PINION DRIVER
(11) Remove pinion seal with a slide hammer or
(12) Remove front pinion bearing and discard bear-
pry bar.
ing.
CAUTION: Do not reuse front pinion bearing/cup.
Fig.55FRONTPINIONBEARINGCUP
(13) Remove collapsible spacer from the pinion
shaft.
1 - INSTALLER 2 - HANDLE
DR PINION GEAR/RING GEAR/TONE RING (Continued)
REAR AXLE - 11 1/2 AA
3 - 151
(2) Install new rear pinion bearing cup (Fig. 56)
with Installer 8968 and Handle C-4171.
(4) Install rear pinion bearing (Fig. 58) with
Installer D-389 and a press.
Fig.56REARPINIONBEARINGCUP
1 - INSTALLER 2 - HANDLE
(3) Install pinion depth shim (Fig. 57) on the pin-
ion gear shaft.
Fig.58REARPINIONBEARING
1 - PRESS 2 - INSTALLER 3 - PINION GEAR 4 - REAR PINION BEARING
(5) Install new collapsible spacer (Fig. 59).
Fig.57PINIONDEPTHSHIM
1 - PINION DEPTH SHIM 2 - PINION GEAR
Fig.59COLLAPSIBLESPACER
1 - COLAPSIBLE SPACER 2 - PINION GEAR 3 - REAR PINION BEARING
(6) Lubricate pinion and bearings.
REAR AXLE - 11 1/2 AA
3 - 152
PINION GEAR/RING GEAR/TONE RING (Continued)(7) Install pinion into the housing and place front pinion bearing onto the pinion shaft. Draw the pinion shaft into the front bearing with Installer 8981 (Fig. 60).
DR
Fig.60PINIONGEARINSTALLER
1 - INSTALLER 2 - DIFFERENTIAL HOUSING
(8) Install new pinion seal (Fig. 61) with Installer
8896 and Handle C-4171.
Fig.62FLANGEWRENCH
1 - FLANGE WRENCH 2 - PINION FLANGE
† New Pinion Bearings: 1.7-2.8 N·m (15-25 in. lbs.)† Original Pinion Bearings: 1.1-2.2 N·m (10-20
in. lbs.)Fig.61PINIONSEALINSTALLER
1 - HANDLE 2 - INSTALLER
(9) Apply a light coat of teflon sealant to the pin-
ion flange splines.
(10) Hold pinion and lightly tap the pinion flange
onto the pinion, until a few threads are showing.
(11) Install pinion flange washer and new pinion
nut.
(12) Hold pinion flange with Flange Wrench 8979
(Fig. 62) and tighten pinion nut until pinion end play is taken up.(13) Rotate pinion several times to seat bearings. (14) Measure pinion rotating torque with an inch pound torque wrench (Fig. 63). Tighten pinion nut in small increments until pinion rotating torque is:
Fig.63PINIONROTATINGTORQUE
1 - PINION FLANGE 2 - TORQUE WRENCH
(15) Rotate pinion several times then verify pinion
rotating torque again.
(16) Position the ring gear on differential case and
start two new ring gear bolts.
(17) Install the rest of the new ring gear bolts and
tighten them alternately to seat the ring gear.
(18) Torque ring gear bolts to 237 N·m (175 ft.
lbs.).
DR PINION GEAR/RING GEAR/TONE RING (Continued)
(19) If exciter ring was removed, position differen- tial assembly on differential Plug 8965 (Fig. 64) and place exciter ring on the differential case.
REAR AXLE - 11 1/2 AA
3 - 153
Fig.64EXCITERRING
1 - EXCITER RING 2 - RING GEAR 3 - DIFFERENTIAL PLUG 4 - DIFFERENTIAL CASE
(20) Install the exciter ring on the differential case evenly with a hammer and brass punch (Fig. 65). Drive the ring down until it is seated against the ring gear.
CAUTION: Do not damage exciter ring teeth during installation.
(21) Install differential in housing and verify gear
backlash and gear contact pattern.
Fig.65EXCITERRINGINSTALLATION
1 - EXCITER RING 2 - PUNSH 3 - RING GEAR
(22) Measure final rotating torque with an inch pound torque wrench. The final pinion rotating torque plus differential case bearing preload is: † New Bearings: 3.4-5.6 N·m (30-50 in. lbs.) † Original Bearings: 2.8-5.1 N·m (25-45 in. lbs.) (23) Install axle shafts. (24) Install the propeller shaft with the reference
marks aligned.
(25) Install differential cover with gasket and
tighten bolts to 40 N·m (30 ft. lbs.).
(26) Fill differential with fluid and tighten fill plug
to 32 N·m (24 ft. lbs.).
DR
BRAKES
5 - 1
BRAKES
TABLE OF CONTENTS
BRAKES - BASE . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
BRAKES - ABS . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
page
page
BRAKES - BASE
TABLE OF CONTENTS
page
page
BRAKES - BASE
DIAGNOSIS AND TESTING - BASE BRAKE
SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
STANDARD PROCEDURE
STANDARD PROCEDURE - MANUAL
BLEEDING . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
STANDARD PROCEDURE - PRESSURE
BLEEDING . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
SPECIAL TOOLS
BASE BRAKES . . . . . . . . . . . . . . . . . . . . . . . . 5
ADJUSTABLE PEDAL SWITCH
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . 6HYDRAULIC/MECHANICAL
SPECIFICATIONS
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
REMOVALREMOVAL - REAR . . . . . . . . . . . . . . . . . . . . . 12
REMOVAL - FRONT . . . . . . . . . . . . . . . . . . . . 12
DISASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . 13
INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . . 14
ASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
INSTALLATIONINSTALLATION - REAR . . . . . . . . . . . . . . . . . 16
INSTALLATION - FRONT . . . . . . . . . . . . . . . . 16DISC BRAKE CALIPER ADAPTER
REMOVAL
REMOVAL - REAR . . . . . . . . . . . . . . . . . . . . . 16
REMOVAL - FRONT . . . . . . . . . . . . . . . . . . . . 16INSTALLATION
SPECIFICATIONS - TORQUE CHART BASE BRAKE
. . . . . . . 6
. . . . . . . . . . . . . . . . . . . . . . . . . 7INSTALLATION - REAR . . . . . . . . . . . . . . . . . 17
INSTALLATION - FRONT . . . . . . . . . . . . . . . . 17BRAKE LINES
STANDARD PROCEDURE
STANDARD PROCEDURE - DOUBLE
INVERTED FLARING . . . . . . . . . . . . . . . . . . . . 7
STANDARD PROCEDURE - ISO FLARING . . . 7REMOVAL
REMOVAL - REAR BRAKE HOSE REMOVAL - REAR TUBE / HOSE
DISC BRAKE CALIPER ADAPTER MOUNT
. . . . . . . . . . . . . . . . . . . . . . 17
REMOVAL - REAR INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 17FLUID
DIAGNOSIS AND TESTING - BRAKE FLUID
CONTAMINATION
. . . . . . . . . . . . . . . . . . . . . 18
. . . . . . . . . . 8
STANDARD PROCEDURE - BRAKE FLUID
LEVEL
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
ASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
. . . . . . . . . . . . . . . 9REMOVAL - FRONT HOSE
INSTALLATION
INSTALLATION - REAR BRAKE HOSE INSTALLATION - REAR TUBE / HOSE
. . . . . . 9
ASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
. . . . . 9INSTALLATION - FRONT BRAKE HOSE
BRAKE PADS/SHOES
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 10DISC BRAKE CALIPERS
DESCRIPTION
. . . . . . . . . . . . . . . . . . . . . . . . . 11
SPECIFICATIONS
BRAKE FLUID . . . . . . . . . . . . . . . . . . . . . . . . 18
FLUID RESERVOIR
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 19BRAKE JUNCTION BLOCK
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 19MASTER CYLINDER
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . 19
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . 205 - 2
BRAKES - BASE
DR
DIAGNOSIS AND TESTING - MASTER
CYLINDER/POWER BOOSTER . . . . . . . . . . . 20
STANDARD PROCEDURE - MASTER
SUPPORT PLATE
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 29CYLINDER BLEEDING . . . . . . . . . . . . . . . . . . 20
PARKING BRAKE
REMOVAL
REMOVAL - ALL EXCEPT HYDROBOOST . . . 21
. . . . . . . . . . . . . 21
REMOVAL - HYDROBOOSTINSTALLATION
INSTALLATION - ALL EXCEPT
HYDROBOOST . . . . . . . . . . . . . . . . . . . . . . . 22
INSTALLATION - HYDROBOOST . . . . . . . . . . 22PEDAL
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . 22
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 23ADJUSTABLE PEDAL MOTOR
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . 24
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 24POWER BRAKE BOOSTER
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . 25
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 25HYDRO-BOOST BRAKE BOOSTER
DIAGNOSIS AND TESTING - HYDRAULIC
BOOSTER . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
STANDARD PROCEDURE - BLEEDING . . . . . . 27
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 27ROTORS
REMOVAL
REMOVAL - REAR . . . . . . . . . . . . . . . . . . . . . 28
REMOVAL - FRONT . . . . . . . . . . . . . . . . . . . . 28INSTALLATION
INSTALLATION - REAR . . . . . . . . . . . . . . . . . 28
INSTALLATION - FRONT . . . . . . . . . . . . . . . . 29BRAKES - BASE DIAGNOSIS AND TESTING - BASE BRAKE SYSTEM
Base brake components consist of the brake shoes, calipers, wheel cylinders, brake drums, rotors, brake lines, master cylinder, booster, and parking brake components.
Brake diagnosis involves determining if the prob- lem is related to a mechanical, hydraulic, or vacuum operated component.
The first diagnosis step is the preliminary check.
PRELIMINARY BRAKE CHECK
(1) Check condition of tires and wheels. Damaged wheels and worn, damaged, or underinflated tires can cause pull, shudder, vibration, and a condition similar to grab.
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . 30
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . 30CABLES
REMOVAL
REMOVAL - FRONT PARKING BRAKE
CABLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
REMOVAL - REAR PARK BRAKE CABLE . . . 31
REMOVAL - RIGHT REAR CABLE . . . . . . . . . 31
REMOVAL - LEFT REAR CABLE . . . . . . . . . . 32INSTALLATION
INSTALLATION - FRONT PARKING BRAKE
CABLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
INSTALLATION - REAR PARK BRAKE
CABLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
. . . . . 32
. . . . . . 33INSTALLATION - RIGHT REAR CABLE INSTALLATION - LEFT REAR CABLE
SHOES
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
CLEANING - REAR DRUM IN HAT BRAKE . . . . 33
INSPECTION - REAR DRUM IN HAT BRAKE . . 33
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 34
ADJUSTMENTSADJUSTMENT - PARKING BRAKE SHOES ADJUSTMENT - WITH ADJUSTING TOOL
. . 34
. . . 36PEDAL
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 36CABLE TENSIONER
ADJUSTMENTS
ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . . . . 37
RELEASE HANDLE
REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 38(2) If complaint was based on noise when braking, check suspension components. Jounce front and rear of vehicle and listen for noise that might be caused by loose, worn or damaged suspension or steering components.
(3) Inspect brake fluid level and condition. Note that the brake reservoir fluid level will decrease in proportion to normal lining wear. Also note that brake fluid tends to darken over time. This is normal and should not be mistaken for contam- ination.
(a) If fluid level is abnormally low, look for evi- dence of leaks at calipers, wheel cylinders, brake lines, and master cylinder.
(b) If fluid appears contaminated, drain out a sample to examine. System will have to be flushed if fluid is separated into layers, or contains a sub- stance other than brake fluid. The system seals
DR BRAKES - BASE (Continued)
and cups will also have to be replaced after flush- ing. Use clean brake fluid to flush the system. (4) Check parking brake operation. Verify free movement and full release of cables and pedal. Also note if vehicle was being operated with parking brake partially applied.
(5) Check brake pedal operation. Verify that pedal does not bind and has adequate free play. If pedal lacks free play, check pedal and power booster for being loose or for bind condition. Do not road test until condition is corrected.
(6) Check booster vacuum check valve and hose. (7) If components checked appear OK, road test
the vehicle.
BRAKES - BASE
5 - 3
HARD PEDAL OR HIGH PEDAL EFFORT
A hard pedal or high pedal effort may be due to lining that is water soaked, contaminated, glazed, or badly worn. The power booster or check valve could also be faulty.
PEDAL PULSATION
Pedal pulsation is caused by components that are
loose, or beyond tolerance limits.
The primary cause of pulsation are disc brake rotors with excessive lateral runout or thickness vari- ation, or out of round brake drums. Other causes are loose wheel bearings or calipers and worn, damaged tires.
ROAD TESTING
(1) If complaint involved low brake pedal, pump pedal and note if it comes back up to normal height. (2) Check brake pedal response with transmission in Neutral and engine running. Pedal should remain firm under constant foot pressure.
(3) During road test, make normal and firm brake stops in 25-40 mph range. Note faulty brake opera- tion such as low pedal, hard pedal, fade, pedal pulsa- tion, pull, grab, drag, noise, etc.
(4) Attempt to stop the vehicle with the parking
brake only and note grab, drag, noise, etc.
PEDAL FALLS AWAY
A brake pedal that falls away under steady foot pressure is generally the result of a system leak. The leak point could be at a brake line, fitting, hose, or caliper/wheel cylinder. If leakage is severe, fluid will be evident at or around the leaking component.
Internal leakage (seal by-pass) in the master cylin- der caused by worn or damaged piston cups, may also be the problem cause.
An internal leak in the ABS or RWAL system may
also be the problem with no physical evidence.
LOW PEDAL
If a low pedal is experienced, pump the pedal sev- eral times. If the pedal comes back up worn linings, rotors, drums, or rear brakes out of adjustment are the most likely causes. The proper course of action is to inspect and replace all worn component and make the proper adjustments.
SPONGY PEDAL
A spongy pedal is most often caused by air in the system. However, thin brake drums or substandard brake lines and hoses can also cause a spongy pedal. The proper course of action is to bleed the system, and replace thin drums and substandard quality brake hoses if suspected.
NOTE: Some pedal pulsation may be felt during ABS activation.
BRAKE DRAG
Brake drag occurs when the lining is in constant contact with the rotor or drum. Drag can occur at one wheel, all wheels, fronts only, or rears only.
Drag is a product of incomplete brake shoe release. Drag can be minor or severe enough to overheat the linings, rotors and drums.
Minor drag will usually cause slight surface char- ring of the lining. It can also generate hard spots in rotors and drums from the overheat-cool down pro- cess. In most cases, the rotors, drums, wheels and tires are quite warm to the touch after the vehicle is stopped.
Severe drag can char the brake lining all the way through. It can also distort and score rotors and drums to the point of replacement. The wheels, tires and brake components will be extremely hot. In severe cases, the lining may generate smoke as it chars from overheating.
slide surfaces.
Common causes of brake drag are: † Seized or improperly adjusted parking brake cables.† Loose/worn wheel bearing. † Seized caliper or wheel cylinder piston. † Caliper binding on corroded bushings or rusted † Loose caliper mounting. † Drum brake shoes binding on worn/damaged † Mis-assembled components. † Long booster output rod. If brake drag occurs at all wheels, the problem may be related to a blocked master cylinder return port, or faulty power booster (binds-does not release).
support plates.
BRAKE FADE
Brake fade is usually a product of overheating caused by brake drag. However, brake overheating
BRAKES - BASE
5 - 4
BRAKES - BASE (Continued)and resulting fade can also be caused by riding the brake pedal, making repeated high deceleration stops in a short time span, or constant braking on steep mountain roads. Refer to the Brake Drag information in this section for causes.
BRAKE PULL Front brake pull condition could result from: † Contaminated lining in one caliper † Seized caliper piston † Binding caliper † Loose caliper † Rusty caliper slide surfaces † Improper brake shoes † Damaged rotor A worn, damaged wheel bearing or suspension component are further causes of pull. A damaged front tire (bruised, ply separation) can also cause pull.
A common and frequently misdiagnosed pull condi- tion is where direction of pull changes after a few stops. The cause is a combination of brake drag fol- lowed by fade at one of the brake units.
As the dragging brake overheats, efficiency is so reduced that fade occurs. Since the opposite brake unit is still functioning normally, its braking effect is magnified. This causes pull to switch direction in favor of the normally functioning brake unit.
An additional point when diagnosing a change in pull condition concerns brake cool down. Remember that pull will return to the original direction, if the dragging brake unit is allowed to cool down (and is not seriously damaged).
