Depending on how tight the clutch plate and pulley are on there, you may need an ordinary steering wheel puller and/or a gear puller. But, probably not.
Just last week I removed the clutch plate and pulley from a SD-709 with only a couple of screwdrivers and a wrench. Some snap ring pliers are handy but not essential.
If you do this pry evenly and only lightly on the fixed part of the clutch plate so you don't distort it. It'll probably come off pretty easy. On the pulley, a couple of large levers worked evenly between the pulley and the front casing of the compressor will usually get it off. If you have any difficulty, look again to make sure you have the snap rings removed.
Go to this thread in the 164 section and download the guide I wrote there. It pertains to a 164, but all are essentially the same:
Also, see this thread by Alfisto Steve on removing the clutch and pulley:
As far as damaging the shaft seal, no, as long as you don't bang on the shaft with a hammer. There is an outer felt dust grommet that you can lift out. It's just a friction fit in the inner section of the compressor's front face pulley boss.
Also look at these web sites. Lots of good information there: