Brake parts for your chassis are not unique to motor home chassis or even to Freightliner .
When I need brake springs and S cam rollers for my front brakes ( 21 years of rust damage ) I walked into the local truck repair shop , with parts in hand and before I got half way to the counter , the parts man said " isle 4 the yellow bin "
a whole milk crate full of the exact parts.
Brake chambers , shoes , S cam shafts ; everything in stock and my home town only has 18,000 people .
BTW: You'll need one of these .
EDIT: Remember the lug nut torque is 450 ft/lbs and retorque in 100 miles.