Differential Output Shaft Bearing: Service and Repair

RENEW

Remove the rear brake disc.

Cut the locking wire and remove the five bolts securing the caliper mounting flange to the final drive.

Withdraw the complete output shaft/bearing assembly and discard the O-ring.

Clean the output shaft/bearing assembly.

Clamp the caliper mounting bracket between suitably protected jaws of a vice.

Fig.1:

Fig.2:

Push back the lock washer tabs and remove the bearing retaining nut (1, Fig.1) from the shaft using Service Tool SL 15A (Fig.2).

Remove and discard the lock washer.

Fig.3:

Withdraw the output shaft (1, Fig.3) from the caliper mounting bracket (2, Fig.3). Collect the inner bearing (3, Fig.3) and cone. Discard the collapsed spacer (4, Fig.3).

Fig.1a:

NOTE: If the outer bearing remains on the shaft and pushes the oil seal out of the caliper mounting bracket on withdrawal, remove it from the shaft using Service Tool SL 47-3/ 1 (1, Fig.1). Pry the old oil seal from the caliper mounting bracket. Collect the outer bearing and cone. Discard the oil seal.

Fig.3:

Using a suitable drift, gently tap the bearing cups (5, Fig.3) out of the housing. Remove the caliper mounting bracket from the vice and carefully clean internally.

NOTE: When bearings are to be renewed, always replace complete bearings. Never fit new cone and roller assemblies into used cups.

Before fitting, new bearings should be lightly greased, but it is most important that at least 4 cc of hypoid oil is added to the cavity between the bearings during assembly, and that the oil seal is lubricated by packing the annular space between its sealing edges with grease. This prevents premature seal or bearing wear before oil flow begins from the axle centre.

Press the cups of the replacement bearings into the housing, using a suitable press and adaptors to ensure that the cups are pressed fully home in the housing.

Place the roller and cone assembly of the outer bearing (already greased) into position.

Fig.2b:

Press the new oil seal into position (1, Fig.2),
ensuring that the spring-loaded sealing edge is adjacent to the bearing.

Load the seal with grease between the sealing edges. Clamp the caliper mounting bracket between the protected jaws of the vice.

Check that the four special bolts for the brake disc are in position in the output shaft flange.

Enter the shaft through the seal and outer bearing.

Fit new collapsible spacer.

Fill the space between the bearings with Shell Spirax 90 oil before refitting the rollers and cone of the inner bearing.

Fit a new lock washer on to the shaft.

Place the nut on to the shaft, grease the face next to the washer and tighten finger-tight only.

Using Service Tool SL 15A and a tommy-bar on the disc attachment bolts to oppose the torque, tighten the nut on the shaft just sufficiently to almost eliminate any play from the bearings. Torque required to turn the shaft should be 0.14-0.0.28 kgf/m (10-20 lbf/in.).

Further tighten the nut, very slightly (not more than a thirty-second of a turn or about 5 mm (3/16 in.) at the perimeter of the nut, and re-check the torque required to turn the shaft. Continue to tighten the nut in very small increments, turning the shaft to seat the bearings and measuring the torque after each increment until the correct figure is reached.

CAUTION: IF THE TORQUE REQUIRED TO TURN THE SHAFT EXCEEDS BY MORE THAN 0.28 kgf/m (20 lbf/in.) THE TORQUE RECORDED IN THE FIRST CHECK, DISMANTLE THE ASSEMBLY, DISCARD THE COLLAPSIBLE SPACER AND REBUILD WITH A NEW COLLAPSIBLE SPACER.

It is not permissible to slacken off the nut after collapsing the spacer, as the bearing cones are then no longer rigidly clamped.

Lock over the tab washers in two places to lock the shaft nut. Remove the assembly from the vice.

Refit the output shaft assembly to the final drive unit.

Refit the brake caliper and disc.

Refit the drive shaft.

SERVICE TOOLS
186 681 Torque screwdriver
SL 15A Spanner
SL 47-3/1 Bearing remover/replacer
SL 47-3/2 Bearing remover/replacer

TORQUE FIGURES
Caliper mounting bracket to unit 81.5-93 Nm
Drive gear to differential flange 102-118 Nm
Radius rod to wishbone 81-94.5 Nm

OILS / SEALANTS / LUBRICANTS
Differential oil Spirax Super 90