Re: Do I have Air Brakes?
No five times? Four for no air brake parts plus one for no hydraulic master cylinder?
I would guess that four out of five means no air brakes, especially with no air canisters behind the rear wheels. But then again, I have no clue what the "dreaded Lucas-Girling air-over-hydraulic brake system" that other members talk about is. They are usually talking about Fords, I think, not GMs.
I have seen vehicles with two air pressure gauges instead of one with dual needles as in the first picture, but I don't think you can make an air brake vehicle without any pressure gauges. Some hydraulic brake commercial vehicles have an optional vacuum gauge so you can be sure that you have enough vacuum for power assist, usually with a big red light for low vacuum. But that gauge is not a requirement.
Regarding the second photo, I have seen some older vehicles with air brakes whose emergency/parking brake is not a yellow diamond like all newer trucks, but I can't remember which ones. Maybe '80s-'90s Prevost coaches had round knobs? Some older buses have a black plastic diamond knob with a round yellow metal insert instead of the yellow plastic diamond. I don't think an '89 would have an older knob, but I don't know for sure.
If the bus has hydraulic brakes, there has to be a master cylinder somewhere, perhaps below the floor instead of on the firewall? You should locate it, because you have to be able to check the fluid level as a preventative maintenance item.
Someone said "Making good decisions comes from experience, experience comes from bad decisions." I say there are three kinds of people: those who learn from their mistakes, those who learn from the mistakes of others, and those who never learn.