Picked up the PB Blaster at Checker Auto this afternoon...sprayed a couple of times. 98 degrees here in Minnesota so I'll try to get to them in a day or so...to hot to work in the barn.
My M5 is probably in the same, or worse condition. One time, I had to take the whole bar off to get better access and really be able to pound on the pins. The other time, I put a jack under the bar so I'm pounding on something solid and not just causing the whole deck to bounce. When you start to lift the whole deck, you know you've got something solid to pound down on. Now I really grease the pins up before putting them back so next time the job is much easier. Good luck.
The first blade change on my Woods M60-4 was a real challenge. I don't think the previous owner ever changed them so it had been some time since they had been off. I ended up using a heavy duty "C" clamp, a large socket and lots of heat. Took two days. Hopefully your efforts won't be as involved. Now the pins are greased at least 2-3 times a season and blade changes take about 5 minutes.