I thought my post might recreate some interest and it did. Tom and Barb posted a nice theory story about how the system works but I didn't see a chart for the various size brake chambers and their allowable stroke . If you don't know the values and the procedure for checking your particular stroke travel which most likely are different from front and rear axle , then you can't possibly understand the concerns of those who know what some of us are referring to.
Another personal observation on my own truck which is equipped with Meritor auto slacks was that EP2 grease was too heavy and they wouldn't adjust automatically. Meritors require EP1.
No you aren't required to cross the scales in Canada with a Motor Home but that is no exemption from having an unsafe vehicle whether you know it or not. California and Florida are two states that I know of that do not require an air brake endorsement and they are legal to drive in Canada if they are legal in the state they are licensed in. However as mentioned that is no excuse anywhere for an unsafe vehicle.
I wouldn't be too surprised if many of the ridiculous comments are coming from people who don't own an air brake vehicle such as "All you need to know is mash the brake peddle"
I'm not sure what that would do for you if you lost air pressure at 60 mph in an emergency stop or brakes out of adjustment.
The OP asked a question and I hope some of the somewhat vague answers created enough interest to answer for himself.
We can't put a two day course of classroom and hands on practical training on
here.
Incidentally the practical part of the test is to be performed once each day the vehicle takes to the road and a written form completed and signed by driver.
Many truckers sign the book and go as well and that is why they get in trouble at the scale or road side check
In ending If you don't know you can't check and you can't check if you don't know.
Good Luck and Merry Christmas to all.