Everyone periodically reads through TSB's for his coach, correct.
Here is one TSB
for the hydraulic system of your 2001 coach.
To find these TSB's for all years you use COM_NET Link
and this one I just picked it from below in the BLTN's group of bulletins.
You would pick your year TSB coach, for your information.
There is one already for the 2020
You may find one for your year coach, say you bought a used coach, if you have no record of it being done Spartan should have it..
Freightliner would be found the same way.