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 year coach's.
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.