This thread is kinda all over the place with everyone's suggestions. but I will give my 2 cents.
Maybe to fix you belt problem you need rix brand belts
... seems to be the answer from what I read.
My experience is that bsp threads seize up in aluminum filter housings....
The steel thread rusts because the moisture sits between the aluminum housing and the fitting.
(In hydraulics its fine even preferable...)
Unless you are using SS fittings....
SS may seem to be the answer but is very expensive and can pickup the treads or not seal very well on the jic mate seat..
If I use bsp in an air system I will nicely wrap a bit of teflon tape (white thicker stuff) on the treads (and I like to use a small film of gasket eliminate locktite on top of the tape). Not to seal pressure. (Thats not how bsp works) but to fill the gap and try to prevent water from rusting the fitting
And tearing out the aluminum threads...
Ps if you ever think you have plumbed your system right..... you will come up with something that you want to add or change etc.....