Air Brake Manual
Air Brake Manual
Air Brake Manual
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· Make a chalk mark where the push rods enter the<br />
brake chambers.<br />
· Reapply spring parking brakes and measure the<br />
distance from the brake chamber to the chalk<br />
mark. Ensure the slack (push rod travel) is within<br />
1/2 - 3/4 inches or within manufacturer’s<br />
specifications and the angle between the slack<br />
adjuster and push rod is 90° or as close as<br />
practical. If not, then a brake adjustment is<br />
required.<br />
The following are recommended adjustment steps<br />
for S-cam brakes with manual slack adjusters.<br />
· Ensure vehicle is secure and wheels blocked,<br />
release the spring parking brake.<br />
· Verify reservoirs are at full pressure.<br />
· Use a wrench to disengage the external locking<br />
device (if so equipped) from the adjustment bolt of<br />
the slack adjuster.<br />
· Turn the adjustment bolt until the brake lining<br />
contacts the brake drum. If possible, visually<br />
check to see that the brake linings are in contact<br />
with the brake drum.<br />
· When turning the adjustment bolt on the slack<br />
adjuster, the S-cam should turn in the same<br />
direction as if a brake application were being<br />
made.<br />
· Back off the adjustment bolt about 1/4 to 1/2 of a<br />
turn. Check that the push rod free travel is now<br />
between 1/2 to 3/4 inches, or within<br />
manufacturer’s specifications.<br />
<strong>Brake</strong> Test<br />
· Reapply the spring parking brake, remove wheel<br />
blocks.<br />
· Gently tug against the spring parking brakes in<br />
low gear, it should hold the vehicle.<br />
· Release the spring parking brakes.<br />
· Move vehicle ahead slowly and make a service<br />
brake application to check brake response.<br />
Combination Unit<br />
When upgrading your driver’s licence from single to<br />
combination vehicles with air brakes, you will be<br />
required to satisfactorily demonstrate the pre-trip air<br />
brake inspection for combination vehicles.<br />
The pre-trip air brake inspection should be completed<br />
within 30 minutes. Failure to complete the test within<br />
30 minutes may result in the test being discontinued.<br />
Practical examination will be conducted in either the<br />
metric or imperial systems of measurement,<br />
whichever coincides with the equipment being<br />
operated.<br />
Vehicle Secure<br />
· Set the spring parking brake on tractor and trailer.<br />
· Block the wheels; the vehicle should be on level<br />
ground if possible.<br />
· Check that the compressor is secure.<br />
· Check the drive belt and pulleys for wear, cracking,<br />
slippage and tension (if equipped).<br />
· Drain all reservoirs completely on the tractor<br />
(wet/supply reservoirs first) then the trailer.<br />
When reservoirs are empty close the drain valves.<br />
“For testing purposes only, the applicant will not be<br />
required to manually drain the reservoirs. Instead,<br />
the applicant will verbally explain the steps that they<br />
would follow when draining the reservoirs and then<br />
fan the brake pedal to empty the reservoir.”<br />
· Check brake chambers, air lines and slack adjusters<br />
for security and wear.<br />
· Ensure the air brake glad hands and trailer electrical<br />
cord is connected properly.<br />
Compressor and Warning Devices Check<br />
· Start the engine and run at fast idle to build up air<br />
pressure.<br />
· Warning device(s) must operate to 55 psi or higher.<br />
· Ensure reservoir air pressure builds from 50 to 90 psi<br />
within three minutes.<br />
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