good chance you'll have to replace some bolts,they're old.
can of WD40 helps. not just 1 type of spanner,use open end,ring,socket spanners and also a socket set with
some extension bars may help.
i found i needed like 2 different spaners just to work 1 bolt from the dump-turbo.
its like a puzzle,can only go together 1 way so you cant really stuff it up.
goodluck