Bronco II 2WD V6-177 2.9L (1986)
Fig. 4 Exploded view of 8.8 inch ring gear axles. Models w/anti-lock brakes
1.
Remove axle cover, Figs. 1 through 4, then wipe lubricant from internal working parts and visually inspect parts for wear or damage.
2.
Rotate gears to check for any roughness, which indicates damaged bearings or gears.
3.
Check ring gear teeth for signs of scoring, abnormal wear, nicks or chips.
4.
On models with 8.8 or 10.25 inch ring gear, proceed as follows:
a. Using dial indicator, check ring gear backlash and ring gear back face runout. Backlash should be .008---.015 inch and back face runout
should be under .004 inch.
b. Do not use contact pattern as a guide to check for noise. Check for proper gear set assembly using pinion depth gauge tool to determine
correct pinion shim required to ensure acceptable running condition.
5.
On models with 6 3/4 or 7 1/2 inch ring gear, test ring gear runout as follows:
a. Install suitable dial indicator and zero indicator, then rotate ring gear and record reading.
b. If reading exceeds .003 inch, check for improper torque of ring gear bolts or dirt between ring and case.
6.
If reading still exceeds .003 inch after step 5b, diagnose ring gear runout as follows:
a. Remove ring gear. 1987 Bronco II models with anti-lock brakes use an exciter ring located on the ring gear assembly. Removal of the exciter
ring is not necessary when removing ring gear on this model.
b. On models with 6 3/4 inch ring gear, install left case on right and tap them together, then place differential cups on differential bearing cone
and roller.
c. On all models, place differential assembly in carrier casting. On models with 6 3/4 inch ring gear, two bolts and nuts must be installed to
hold case halves together.
d. Install .265 inch shim on left side as guide.
e. Install left bearing cap and tighten bolts finger tight.
f.
Install progressively larger shims on right side until largest shim selected can be assembled with a slight drag feel. Apply pressure toward
left side to ensure that bearing cup is seated.
g. Install right side bearing cap and torque differential bearing cap bolts to 70---80 ft. lbs., then rotate assembly to ensure free rotation.
h. Check runout of differential case flange with dial indicator. If runout is within .003 inch, install new ring and pinion gear. If runout exceeds
specifications, trouble is due to either a damaged case or worn bearings.
i.
Remove differential case from carrier and the differential bearings from case.
j.
Install new differential bearings on case hubs and install differential assembly in carrier less ring gear.
k. Check case runout. If runout is within .003 inch, use new bearings for reassembly. If runout is still excessive, case is damaged and must be
replaced.
7.
Remove axle shafts.
8.
Mark relationship of driveshaft end yoke and axle companion flange for proper assembly, then disconnect driveshaft at rear axle universal joint.
9.
Install inch pound torque wrench on pinion nut and record torque required to maintain rotation of pinion through several turns.
10.
Using suitable tools, hold companion flange and remove pinion nut.
11.
Clean area around oil seal and place drain pan under seal.
12.
Mark relationship of companion flange to pinion shaft for proper assembly, then, using suitable puller, remove companion flange.
13.
Using suitable tool, remove pinion oil seal.
14.
Mark one differential bearing cap to ensure proper positioning of caps during assembly. Do not interchange left and right bearing caps.
15.
Loosen differential bearing cap bolts and bearing caps, noting direction of triangles on bearing caps for proper assembly.
16.
Pry differential case, bearing cups and shims out until they are loose in bearing caps, then remove bearing caps and pry differential assembly from
carrier. When using pry bar, place a wood block between pry bar and axle housing to protect casting face from damage.
17.
Using suitable mallet, drive pinion out of front bearing cone and remove through rear of carrier casting.
18.
Using suitable tools, remove pinion rear cone and roller bearing assembly, then, using micrometer, measure and record thickness of shim found
under bearing cone.
19.
Remove damaged pinion bearing cups from carrier by tapping alternately with brass drift on opposite sides of cups to prevent cups from cocking
in casting.
Final Assembly & Adjustment
1.
If removed, install new bearing cups using suitable tool. Ensure that cups are properly seated in their bores. If a .0015 inch feeler gauge can be
inserted between a cup and the bottom of its bore at any point around cup, the cup is not properly seated. Whenever cups are replaced, the cone
and roller assembly should also be replaced.
2.
Using proper rear axle pinion depth gauge tool, assemble appropriate aligning adapter, gauge disc and gauge block to screw.
3.
Place rear pinion bearing over aligning disc and insert it into rear pinion bearing cup and assemble tool handle to screw. Roll assembly back and
forth a few times to seat bearings while tightening tool handle by hand. Torque tool handle to 20 ft. lbs. The gauge block must be offset 45° to
obtain accurate reading.
4.
Center gauge tube into differential bearing bore, then install bearing caps, torquing bolts to 70---85 ft. lbs. Select thickest shim that will enter
between gauge tube and gauge block. Insert shim directly along gauge block to insure a correct reading. The shim fit should be a slight drag-type
feel. Shims used for gauging must be flat to obtain correct feel.
5.
Place selected shim(s) on pinion and press pinion bearing cone and roller assembly until it is firmly seated on shaft. The same rear pinion
bearing used in this procedure must be used in final assembly of axle. Ensure that press load is not applied to bearing cage.
6.
Check splines on pinion shaft to be sure that they are free of burrs. If burrs are evident, remove them with a fine crocus cloth, working in a
