How to replace lower motor mount?

[MoVolvos]

Also, by jacking up the engine, am I likely to break anything, this is the major concern for me right now, what should I remove or disconnect in order to prevent that? I’ve got 3 of the 4 arm bolts loose, just that one which is blocked by the engine to get, bit nervy as I’ve never attempted this on this car before.

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Pretty standard to put a piece of wood under the engine per FCP. Have not seen a write up or warning before about cracking the pan. Use an appropriate sized piece to evenly and flatly distribute the load. Not too high also as other mounts and things (?) are attached. I owned the 98 S70 T5 in the early 2010 and replaced it twice, both FCP parts so not the freshest in my mind in terms of R&R. You should be fine regardless.
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[volvolugnut]

Use good sense for the board - 2 x 4 or 3/4 plywood. Don't try with thin plywood or OSB panel. You want the board stiff enough not to flex and allow a high load in the center of the pan. Get a board long enough to span the width of the pan.
volvolugnut

[foggydogg]

It has been a while since I had to deal with four-bolt subframe stuff, but I think I used an offset box end wrench to get to that bolt, one flat at a time. Pretty slow slogging, and I didn't bother replacing that bolt, just left it in situ. The engine shouldn't need to be raised much, just an inch or 2 (dunno what that is in metricspeak), and if that is the plan a suggestion would be to remove the nut from the bottom of the front hydraulic mount to keep from stretching it.
(As a side note, this thread was started about the mount by the crankshaft damper pulley.)