Just thought I'd document some comments on rear swinging arm bearing relacements:

The bad point about the bearing design is the use of re-greasable bearings instead of sealed-for-life (taper-roller)coupled with their location and poor protection from ingress of water. The bearing change is not the difficult part of the job. The
difficulty in a car which has never had it done before is as follows:

Locking pin keeping the hydraulic strut and swinging arm connected together
Its a steel pin passing through aluminium alloy, hardened steel and aluminium alloy again. The corrosion causes the pin to be siezed in place and its a &^%$£%^ to get out. Heat, sweat and LOTS of foul language are the only tools I have found to work. Drilling is a non starter becuse the pin is hardened.

Sphere
To get the sphere off you need to hold the strut still. The only mechanism to prevent it from rotating is a small rolled dowel pin which sticks out from the strut at 90 degrees. It locates in a groove in the chassis leg but it is not very strong. Coupled with the fact that the galvanic corrosion between the pin and the strut rots the strut at this point. If its really stuck a combination of heat, shock and stilsons with a Pleiades sphere tool is the only solution I have found to work.

Anti Roll Bar securing bolts
These are VERY tight, they are put on with threadlock, access is difficult (but not impossible) with a socket, they corrode due to the steel/aluminium alloy interface.

Brake pipe
The brake pipe is exposed to the elements in this location and the inevitable corrosion sets in. The quadrangle plate holding the pipe secure to the swinging arm always rusts. Getting the securing bolt loose and getting it off the pipe usually ends up with pipe fracture. If the flare nut at the caliper end is original it will be steel and hollow. Getting it out intact is nigh on impossible.

Once the above 4 obstacles have been overcome, the rest of the job is
reasonably straightforward. The usual modification done by the DIYer
is to add a grease nipple to the hollow part of the swinging arm and
once reassembled, pump it full of grease until it comes out the ends.

I hear, however, Pleiades have produced (read 'sold on from a bearing
manufacturer') a sealed-for-life bearing. In which case there would be no need
for the grease nipple.

The non-sealed-for-life bearings are only £8 per pair so in total cost terms the bearings were never the issue. The above problems with removal is by far the costliest part of the whole job.

For interests sake I have taken upwards of 4 hours to get a single strut off in the past. However, if all the parts are greased prior to re-assembly the job becomes much easier. e.g. I can have the rear strut of my XM out in my hand in 15 minutes from putting the kettle on and jacking the car up. I've done it twice since in order to repair a leaky seal in the strut so this is an accurate assessment.

Hope this helps anyone with sagging rear swinging arm bearings.

Cheers

noz