air regulator question

[bevans6]

John, I did in fact document my procedures, in another thread on testing air brakes.  My understanding, from my air brake course and from reading, is that after a certain point in the late 1970's air pressure gauges, by regulation, had to read the pressure in the service tank (also known as the dry tank).  My thinking is that's the best place for a single gauge to read from, it tells you the most important pressure.  If I was going to add a gauge for operational use, it would be to the parking brake tank.  If I was going to troubleshoot air systems seriously, I would add a gauge to the accessory tank system (already have, actually) and a manual valve so I could isolate it from the rest of the air system, maybe with a tee so i could add air just to the accessory system and look for leaks without having to annoy my mosquitos by running the bus all the time!

My bus got a "DOT" inspection and $3K worth of brake work just days before I got it - the deal was it came with new brakes.  A highly reputable trucking company with a large shop did the work.  there was no audible low air alarm - big $ ticket and sitting by the side of the road if you got stopped and inspected, and the front slack adjusters were "adjusted" so that the available travel was exceeded, the canisters bottomed out and there were no front brakes - both actively dangerous, and the big $ ticket and call out a tech to adjust them.  In Ontario, where I live, you have to be licensed to do brake adjustments, and while there may be an exception for privately owned vehicles, they sure don't advertise it.  Brand new shoes, not working brakes.  And it had a Ministry of Transport safety certificate issued.  so I have no inherant respect for DOT inspections, but huge respect for knowing how to do them so you can check the work myself.  hence my quest for knowledge...

If you have an air dryer between your compressor and the wet tank, then it has a check valve that is intended to retain air pressure in the wet tank when the air dryer purges.  the only time reed valves in the compressor should see continuous pressure that they could leak is if the bus is turned off during a compressor cycle, at that time it will see any air pressure in the line from the compressor head up to the air dryer, and whatever is inside the air dryer.  Even if that leaks down, the check valve is supposed to retain air inside the wet tank.

Brian

[JohnEd]

Brian,

Thanks for the info.  I have always had the highest regard for the Kanuk DOT inspection systems.  Sorry to hear that they aren't as good as I had heard and hoped.  I think the nice thing about your system is the licencing and the fact that you can actually grip to someone that wants your vote and that guy can screw with their permits to do the tests and MAKE A BUCK.  That always get attention....as it does with me.

What is the thread that you already posted?  I assume that it compliments this one.  Actually, I am interested in anything you post and will start looking at your past posts.  Still need that reference. though.

My sincere thanks for your consideration and sharing the results of your good work.

John

[pvcces]

Hey, guys, keep up the good work.

Our gauge is connected to the auxiliary tank, and that works fine. However, I got ambitious one day and installed a dual needle gauge. The second needle is connected to the treadle valve so that I can see how much pressure is requred for downhill braking. I like that much better.

I have often seen that the auxiliary tank gauge was reading zero after setting overnight and then stepped on the treadle and found that I had air for the brakes. I had realized that the the system could be figured out by using the various cues, but I had never got around to analyzing it.

I'm glad to see that work all in one place, even if there are some differences between our system and the one that was the subject in the writeup. Thanks a bunch, Brian.

Tom Caffrey

[bevans6]

John, here is the thread I referred to:   http://www.busconversions.com/bbs/index.php?topic=12988.0

Brian

[buswarrior]

An inspection of any kind is only as good as the person doing it.

Training is a far cry from what most think it is.

And where their value system has been bent over the years of trying to stay employed and/or solvent.

Busnuts would be well advised to do their own reading and pay close attention if they are paying for things done by others who are supposed to have credentials.

happy coaching!
buswarrior