Lesson 3/Learning Event 3
Learning Event 3:
INSPECTION AND ROAD TEST
The inspection and road test of wheeled vehicles to determine the
condition of the brake system is about the same regardless of whether
the brakes are air or airhydraulic. Therefore, except for a few
special airbrake components, the inspection and test is made similar
to that for 2 1/2 and 5ton vehicles.
The inspection consists of checking the air hoses, fittings,
chambers, cylinders, and linkage for looseness or damage. Also check
for water in the air reservoirs. Then start the engine and observe
the air pressure buildup. Check for leaks in the lines, fittings,
and components by stopping the engine and seeing if the air pressure
gage drops noticeably in a period of one minute. If it does, more
testing for leaks is required.
If a visual inspection indicates that the brake system seems to be in
good condition, roadtest the vehicle to see just how well the brakes
operate. During the road test, check for side pull, noise, or
clatter. Make several stops to be sure of this check. Immediately
after the road test, check the temperature of the brake drums. If
they are too hot, the brakes are dragging; if one is too cool, the
wheel brake is not operating.
If any deficiencies are noted during the inspection and road test,
they must be corrected. We will discuss some of the test and
replacement procedures for those airbrake components that are
different from the ones on hydraulic or airhydraulic systems. Table
1 provides a troubleshooting guide for the service brake system.