Hi
I think the easy way to do this is easy take the rear drums off cheeck the wheel cylinders for leaks replace the shoes if nessery
go to the front remove the calipers and get them serviced ask google this
stainless steel wheel cylinder inserts australia
ring a few and get some prices
you might as well get the master relined as well
for recomadtion of any of the compneys you speek to go to
https://ozvolvo.org/
all easy and the only safe way
there other ways but this is the easy root
only a weekend work
ask the OZ guys for a green book its the volvo workshop book