JP,
Well, in reality, there's not too much to do in terms of maintenance. A visual inspection is warranted on an every so often basis, all depending on just how much annual driving is done and, just what kind of driving is done.
I say "kind" 'cause, you pull a toad and, do NOT have auxiliary braking in it, you will use your coaches brakes to slow down and stop the toad. That means just a tad more wear would be if there was auxiliary braking but, not much. And, if you do a lot of down grades where you have to assist your exhaust or Jake brake systems, you will put a tad more wear on them but, again, not much.
An Exhaust brake or, a Jake (compression brake) adds some serious extra long service life to your regular brakes, as long as you use either correctly.
Now, on occasion, some air brakes will develop some form of a "clunk" (description subjective) as slow speed application is applied in places like say, a parking lot, slow speed city streets etc. That "clunk" is primarily due to sticking S-cam parts in the operation of those brakes. This clunk, is not life threatening but, it is a nuisance.
To correct it, it's a matter of removing the wheel/tire assembly, backing off the slack adjuster to the point that those S-cam components can be removed from the ends of the brake shoes and, cleaned up and lubed, ( a very tiny amount of lube in the correct spots only). Then, all is reassembled and, the slack adjuster is brought back to correct adjustment and, the tire/wheel assembly is re-installed and the lug nuts torqued to the proper tightness.
And, speaking of slack adjusters, about 99.999% of the air brake equipped coaches have them. In short, they are primarily the main way of keeping the "Slack" out of the brake shoe application to the drums/discs. They are a geared mechanism that, is attached to the brake air cans in such a manor that, they move right along with the shoes etc.
But, they are connected in such a manor that, they see just how much "throw" is needed to apply the set of shoes they are attached to. If, they see TOO MUCH throw, they go into action and, by virtue of their design, mechanically adjust the amount of throw so there's minimal action needed to apply the brakes.
The maintenance side is simply lubing them, and other lube points pertaining to the brake system parts (with a grease gun).
Most air brake shoes will last way over 100K miles and even close to 150K or more. Again, it helps to use your E-brake or Jake brake as required.
So, a visual inspection, which can be done by laying on the ground, and, with the use of a mirror and flashlight, to check for general condition of the shoes and drums or pads and discs, should be done on at least an annual basis. There are rules for the periodic application here. I never go by the rules 'cause I do all my own work which, is seriously more frequent than the rules call for.
Then, a lubing every so often of all the brake related components (NOT IN THE SHOE/DRUM area) is also required, usually with the lubing of the rest of the chassis. Hope this has helped some.
Scott
