Air Brake REFRESHER and TEST procedures incl. Leak test

[dentmac]

Safety FIRST.
-The operating range for an Air Brake system must be between 80 and 135 psi.

-With the engine between 600 and 900 rpm , the cut in pressure for the compressor must be above 80 and the cut out must be below 135.
---------------- With the engine running and the emerg. brake set , fan the brake peddle (on and off) and note the cut in pressure, then wait to note the cut out pressure.

-The low pressure warning alarm must come on above 55 psi (usually 60)
-----------------With the engine not running and the spring/emerg on , fan the brake peddle until the light/alarm comes on. The warning light/sound must occur before the gauge reads 55 psi.

Note that the Spring/emerg brakes will automatically activate near or below 55 PSI

-Pressure build up timing will check the compressor. The build up from 85 to 100 psi must be under 2 minutes at 600 to 900 rpm
----------------- After the previous test (or with the pressure below 80 psi) and the emerg brake on. Start the engine and with the idle RPM (between 600-900) , record the time required to go from 85 to 100 PSI. This must be under 2 minutes.

-Check for leaks. a maximum of 3 psi per minute is allowed.
----------------With the pressure above 100, the spring brakes OFF and the engine not running, apply and hold significant pressure on the peddle. Note the pressure loss per minute. (easiest to hold for 2 or 3 minutes and average since 3 pounds is difficult to read on the gauge.)

Check Spring brakes,
---------------With the emerg. brakes set, put the transmission in gear and slowly add a little engine power. The vehicle will not move if the Spring brakes are functional.