The jack should look like the photo in 98 FPAs post, Howere, it sounds like yours is the same as mine, and the spring is on the side and blocks the bolts. not sure if it creeped this way over the years or what, but theres no way they could have originally mounted it like that..
You might be able to use a pry bar and twist the spring so it faces the back. If it wont twist, lower the jack and put some wooden wedges in the spring coils, then raise the jack, This may take enough force off the top spring mount so you can twist it toward the back, or remove the spring. and get to the bolts..
As for rebuilding, some of the jacks are deemed unserviceable and they don't sell parts for them.. NOT A PROBLEM.. On my front jacks, I was able to make a new top guide, and install new o-rings and scrapers. The new o-rings and scrapers was about $10.
Power Gear 500384 hydraulic jack re-assembly – 1999 Southwind 35S
Power Gear 500384 hydraulic jack teardown – 1999 Southwind 35S