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| This
time study was performed by an independant
large fleet maintenance department. |
| Previously,
this fleet was using the mark and measure method
to check pushrod stroke on a mileage schedule. |
Three
methods were studied with the following results.
|
| Method
1. Mark
and Measure: |
Marking
each pushrod at the brake chamber face
with a chalk (10 pushrods).
Applying the service brake (air pressure set at 90 psi).
Measuring each pushrod stroke.
ELAPSED TIME = 25 MINUTES |
|
| This
is the conventional method. |
| |
| Method
2. Adjusting Slack: |
Adjusting
each slack by bringing the brake linings
to contact the brake drums and backing
off one half turn (10 slacks).
ELAPSED TIME = 11 MINUTES |
This
method is only acceptable with manual slack
adjusters. Adjusting auto slacks in this manner
is often mistakenly used by maintenance personnel
when brake stroke checks are requested. To
adjust auto slacks in this manner instead of
actual brake stroke measurement is not reliable.
Seldom is there a check to verify proper operation
of the auto slack adjusters or to verify that
the pushrods are operating within the readjustment
limits.
|
| |
| Method
3. The Solution: |
|
With Safety-Check™ brake
gauges installed and with brakes released,
check that the clevis pin indicators
are touching the front gauge pins.
This position assures that the pushrods
are at the fully released positions
and not hung up.
Apply service brake (air pressure set at 90 psi.)
Check that all clevis pin indicators are not touching the rear
gauge pins.
ELAPSED TIME
= 3 MINUTES
|
Not
only is this the fastest method, but it has
the added benefit of confirming that all
brakes are releasing correctly. The time
savings can be even greater, since NO tools
are required and adverse conditions have
little effect.
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