Scott
It is best to try and match the parts you have as Beaver or more accurately in this case Safari motor coach made running changes through their production on their Magnum chassis.
Let's start with some of the basics does your coach have air over hydraulic disc brakes or hydraulic over hydraulic ( power steering pump ) over .
Or does it have true air disc brakes.
Does your coach have ABS.
Is the parking brake a drum brake or a disc brake on the bake of the transmission
If you coach is air over hydraulic this link may help
https://beaveramb.org/forum/index.php/topic,12458.msg81857.html#msg81857Eric