I have a '98 V70 which has a bad upper spring seat in the passenger front. my car has 175K miles on it and I don't know if the struts in the front have ever been changed. they feel O.K. and don't excessively bounce over rough terrain. first of all, if I change one spring seat on one side, should I do the other side at the same time? As well, should I just replace the struts too? (again, the struts don't seem bad, I just don't know how old they are)

 

I would do both spring seats at once. If the struts feel fine leave them the way they are.

 

When you replace upper spring seats, is it essential to get an alignment? I have an AWD V70. if I tackle this job myself, I assume I need a spring compressor, is it a relatively easy job?

 

You really don't need to get an Alignment right away.
There is only really minor movement with the bolts loose. Not enough to mess up the alignment to bad.
If it was done under Warranty Volvo would NOT pay for an alignment.

It really isn't that bad to do. Yes you will need a spring compressor.
You will need for tools:18mm Wrench,17mm Socket,15mm Socket,13mm Socket,Channel locks,13/16 Socket or 21mm Socket,Maybe a T-45 socket bit or Visegrips. Depending on exact year and Chasis.The center of the strut might be a Torxes or just a Flat spot.

I remove the ABS sensor out of the strut.Then the 1 bolt for the Sway bar link. Then the 2 bolts for the strut.
Then the 3 13mm's up top and it should slide out. Then you need the spring compressor.

Tip: atleast break the top nut loose if you can before you drop the strut. If not it might be a pain without Impact wrenches.

 

Also have a bad spring seat. Haven't done it yet but been gather info. Here is a link on how to avoid alignment

http://volvospeed.com/vs_forum/index...opic=40453&hl=