IRS AXLE - BEARING REPLACEMENT
To get the drums off, you'll need a 36mm socket (3/4" drive) with a solid breaker bar (no swivel) and a 4 ft stout pipe extension.
Have someone stand on the brakes while removing the nut.
Check the CV joint bolts; you'll need the correct tool for the bolts on your model. Clean out the bolt head recesses so the tool will fit all the way in. This is a good time to lube the CV joints as well.
Also a good time to redo the brakes while the drums are off.
The stub axle can now be driven out with a soft mallet. It usually comes out easily.
There are 2 grease seals, one in the bearing cap and one in the rear of the axle housing. Remove them. Next is a giant circlip in the rear part of the axle housing. Remove that to gain access to the inner (ball) bearing. You can drive the inner bearing out using a drift from the outer end of the housing. It will come out as one unit; the races are not separable.
The outer (roller) bearing has a separable inner race.
Drive the outer bearing out from the rear.
All side loads are taken by the ball bearing (and the circlip!).
The 2 bearings are clamped together by the nut, drum and the 3 spacers. The roller bearing is there to carry most of the radial load.
The inner and outer spacers double as the sealing surfaces for the grease seals. The inner spacer may be hard to spot; it often looks like part of the stub axle flange.
Clean the old grease out and refill with wheel bearing grease. Don't overfill the hub; the grease needs room to move around. Pack the bearings with grease also.
Install the bearings by lightly tapping on the outer race only. If you can, make up some kind of sleeve to match the bearing OD.
Re-install the CirClip.
Carefully install the seals and lubricate the lips.
If you can't find replacement O-rings, RTV sealant or similar works well to seal the bearing cap to the housing.
Grease seal (2) 113 501 315G
Inner bearing 113 501 283
Outer bearing 113 501 277A
Tighten the axle nut to 250 Ft-Lb.
Tighten the CV joint bolts to 25 Ft-Lb.
(After losing a CV joint once, I now impact them on and inspect them periodically for loose bolts.)
There is an exploded pic (from Haynes) of the axle assembly: