Good advice from Roland,as always.
The cork gasket lasted 40 years, or so why reinvent the wheel, although nothing wrong with neoprene.
3 out of 4 lip seals on the hydro are replaceable from the exterior. as well as
the charge pump "O" ring.
The 4th behind the trunion requires disassembly of the hydro.
The fact your asking questions here, would lead me to not advise a novice to try it.
I'd advise,
repair yer bolt problems, and of course the cork gasket as you have it off, and if you want to fix, what is not leaking, as far as seals, your call.
If you want to replace axle seals as you have the housings off, no problem there.
The rear cover gasket is a no brainer.
