To obtain your Class “B” license you must complete the DMV Pre-Trip and road test. Below are some useful tools to help you be successful the first time. If you have any questions please contact us at In-Service Training (213) 485-6087.
Air Brake Check (for air brake equipped vehicles only)
All items marked with an asterisk (?) are critical parts of the in-cab air brake test and must be demonstrated during DMV testing. They may be performed in any order. If these items are not performed correctly, it is considered an automatic failure of the pre-trip test. The driver must verbalize and demonstrate the air brake test.
• C = Air compressor cuts in.
• O = Air compressor cuts out.
• L = Low pressure warning.
• A = Air leakage.
? Check air compressor governor Cut-in pressure With the compressor off, and the engine idling, reduce the air tank pressure sufficient to cause the air compressor to cut-in (the gauge pressure will begin to rise). The air compressor must cut-in no lower than 85 psi.
? Check air compressor governor cut- Out pressure
Run the engine at a fast idle. The air governor will cause the compressor to cut¬-out at 130 psi/max; normal acceptable cut-out range is from 110 to 120 psi. The air pressure shown by the gauge(s) will stop rising.
? Test Low pressure warning signal
With the engine off, low pressure warning device must activate between 55 and 75 psi.
? Test Air leakage rate
With a fully-charged system (typically 125 psi), turn off the engine, release all brakes and then apply full steady pressure to the brake pedal (brake on) and hold (for one full minute.) After the initial pressure drop, the air pressure should not fall more than:
• 3 psi in one minute for single vehicles, or
• 4 psi in one minute for combination vehicles.
Note: The COLA test may be performed in any order. The following order is “RECOMMENDED” for LAFD vehicles:
(1) Cut-in pressure.
(2) Cut-out pressure.
(3) Air leakage rate.
(4) Low pressure warning signal.