Page K-10
Repair and Service Manual
B
MECHANICAL BRAKES
Read all of Section B and this section before attempting any procedure. Pay particular attention to Notices, Cautions, Warnings and Dangers.
soon as the accelerator pedal is depressed.
Fig. 10 Parking Brake Pedal Hinge Inspection
To prevent serious injury or death from the use
of worn parking brake components, do not
attempt to re-new worn components. The park-
ing brake latch arm, kick-off cam and catch
bracket are hardened parts. Do not grind or file
them as doing so will cause the parts to lose
their hardness characteristics. New parts must
be used.
10.
Inspect catch bracket and latch arm.
Replace if showing signs of wear or damage (Ref. Fig.
11).
11.
Inspect the parking brake kick-off cam.
Look for wear and for correct adjustment. With the
parking brake engaged and fully latched, there must
be no gap between the top of the cam and the latch
arm. Adjust the kick-off cam (3) if required (Ref. Fig.
11). It is very important that the correct setscrews are
used to hold the kick-off cam to the pivot rod. Use of
longer screws prevents correct adjustment of pedal
bumper (pedal travel) and may prevent the brakes
from adjusting properly.
12. Inspect kick-off cam linkage and bushings.
Check for wear and damage. The kick-off cam pivot
and bushings should move freely and be free of corro-
sion. The kick-off cam should rotate when the acceler-
ator pedal is depressed.
Fig. 11 Kick-off Cam Inspection
Periodic Brake Performance Test (PBPT)
To prevent severe injury or death resulting
from operating a vehicle with improperly oper-
ating brake system, the braking system must
be properly maintained. All driving brake tests
must be done in a safe location with regard for
the safety of all personnel.
The Periodic Brake Performance Test (PBPT) should be
performed regularly (see Periodic Service Schedule in
the GENERAL INFORMATION AND ROUTINE MAIN-
TENANCE section of this manual) as an evaluation of
braking system performance. It is useful as a method of
identifying subtle loss of performance over time and as
part of troubleshooting a problem vehicle.
Before performing this test, inspect the brake pedal and
linkage and correct any problems found including adjust-
ing the brake pedal free travel if required.
The purpose of this test is to compare the braking per-
formance of the vehicle to the braking performance of
new or “known to be good” vehicles or to an established
acceptable stopping distance (see below). Actual stop-
ping distances will be influenced by weather conditions,
terrain, road surface condition, actual vehicle weight
(accessories installed) and vehicle speed. No specific
braking distance can be reliably specified. The test is
conducted by latching the parking brake to eliminate dif-
ferent pedal pressures and to include the affects of link-
age mis-adjustment. Significant changes or differences
in braking performance will be evident due to mis-adjust-
ment.
Establish the acceptable stopping distance by testing a
new or “known to be good” vehicle and recording the
stopping location or stopping distance. For fleets of vehi-
Torsion
Springs
Hinge
Pin
Push
Nut
Kick-Off
Cam
Set
Screw
Pedal Latch Arm
Catch
Bracket
Cam Must Be Against
Latch Arm At This Point
0.0" Gap
(0.0 mm)
Summary of Contents for EXPRESS L6 2012
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