B
BRAKES
Read all of SAFETY and this section before attempting any procedure. Pay particular attention to Notices, Cautions, Warnings and Dangers.
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Repair and Service Manual
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Figure 13 Periodic Brake Performance Test
NOTICE: Over time, a subtle loss of performance
may take place; therefore, it is important to estab-
lish the standard with a new vehicle.
Drive the vehicle at maximum speed on a flat, dry, clean,
paved surface (Figure 13). Quickly press the brake pedal
to latch the parking brake at the line or marker in the test
area and remove foot from pedal. The vehicle should stop
aggressively. The wheel brakes may or may not lock.
Observe the vehicle stopping location or measure the
vehicle stopping distance from the point at which the
brakes were latched. The vehicle should stop within the
“normal” range of stopping distances. If the vehicle stops
more than 4 ft. (1.2 m) beyond the acceptable stopping
distance or pulls to one side, the vehicle has failed the
test.
Repeat test two more times.
If the vehicle fails to pass two of three Periodic Brake Per-
formance Tests, perform the Aggressive Stop Test 10
times as described below, then repeat the Periodic Brake
Performance Test three more times (second set of three).
If the vehicle passes two of three Periodic Brake Perfor-
mance Tests, check that the clevis pins at the brake
levers are loose. If they are loose, return vehicle to ser-
vice. If they are tight, adjust free travel. See the
Then repeat the Periodic Brake
Performance Tests. If vehicle fails, remove from service
and refer to ‘Wheel Brake Inspection’, to evaluate the rea-
son for failure.
Aggressive Stop Test
To prevent serious injury or death,
all brake tests must be done in a
safe location with regard for the
safety of all personnel.
Always conduct a visual inspection and evalu-
ate pedal travel before operating a vehicle to
verify some braking function is present.
The purpose of this test is to attempt to fully expand and
release the brake adjusters on a vehicle which has failed
the first set of Periodic Brake Performance Tests. It is
important that the technician/mechanic exercise care and
perform the test in a non-congested area with regard for
the safety of all personnel.
To perform an Aggressive Stop Test, equally load both
sides of the vehicle (Figure 13) and apply maximum force
and travel to the service brake pedal while moving. Do
not latch the parking brake. Do this a total of 10 times with
the first few at slow speed. If brake function is adequate
or improves, increase speed for the remaining tests.
Before the end of the tests, both wheels should lock at
approximately the same time and slide straight.
NOTICE: The brake adjuster mechanism must
expand and release fully to function. Under light
usage this may not occur, even though the vehicle
stops acceptably. The adjuster functions most con-
sistently with aggressive braking.
Latch
Parking Brake
and Take Foot
Off Pedal
Line or Marker
Acceptable
Stopping
Distance
Normal Range of
Stopping Distance
Any vehicles that stop
more than 4 ft. (1.2 m)
beyond the Acceptable
Stopping Distance or
pulls to one side should
be removed from service
and inspected by a
qualified mechanic
Accelerate To
Maximum Speed
4 ft. (1.2 m)
Line or Marker
Dry, Level, Clean, Paved Surface
