I wanted to pass on a simple tool or tools you can make if you need to release the locking mechanism on a DOT push on air fitting. I had to change many times some of my air fitting configurations on my bus and got so dam pissed trying to unlock the push on type fitting until I come up with this after trying using a screw driver, plyers , my finger nails etc. like I know you have too.
Just go to a flea market and get a 1/4", 3/8", 1/2", 5/8" wrenches to match the most common sizez of DOT tubing used on our buses. Pay only a 25 cents or so for them. Then put them in a vice one at time and use your acetlyene torch to heat up the wrench near the open end of the wrench and hit easily with a hammer to bend the wrenchs to about 45-60 deg. I would say or what would be comfortable to you to use. Look at my photo and judge for yourself. Maybe a perfect 90 deg. bend or a little less will be easier to get a good shot at breaking the locking mechanism loose.
The above diameters of the wrenches are exactly what the outside diameters of the DOT tubing is and this gives you over 50 % of the diameter of the fitting to press in to release the locking feature of the fitting.
Here is a tip too, before trying to pull out the tubing, push the tubing in more to bottom the tubing out inside the fitting as you pull back on the wrench. Put your thumb on the bottom of the fitting as you support the wrench against the locking lip of the fitting as in the photos included here and pull out on the tube with a sharp yank, the tube should come out pretty easily, it may take a second shot to get the jist of this but you will thank me one day and not get pissed at trying to do this.
Gary
![Image](http://i629.photobucket.com/albums/uu19/busconverter101/Conversion%20of%20DD3%20Brakes%20to%20Spring%20Brakes/P1000271.jpg)