TrailMax FWTD-50-T, Manual

Page: 33 / 58

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page 33
FWTD-50-T (17.5)
Maintenance
a. Measure the applied stroke. Using a ruler, measure the distance from the face of
the air chamber to the center of the large pin in the clevis. (Another method is to mark
the shaft where it exits the chamber). Make a 100 psi brake application and allow the
chamber pushrod to travel to its maximum stroke. Again, measure the distance from the
face of the chamber to the center of the large pin. The applied stroke is the difference
between the two measurements. If this distance is less than 2", then the slack adjuster
is functioning properly. If the applied stroke is more than 2", proceed with step b.
b. Measure the free stroke. Make the same two measurements as described above
for measuring the applied stroke, but instead of air pressure use a lever to move the
slack adjuster arm until the brake shoes contact the drum. This distance should be
between
1 /
2
" to 5 /
8
".
If the free stroke is good but the applied stroke is too long then there is a problem
with the foundation brake. Check the foundation brake for missing or worn compo-
nents, cracked brake drums, or improper lining to drum contact.
If the free stroke is less than 1 /
2
", then a dragging brake can occur. Readjust the
slack adjuster manually as described below.
If the applied stroke is good but the free stroke is greater than the recommended
distance (
1
/
2
" to
5
/
8
"), then a function test of the slack adjuster should be performed as
described below.
M
A
I
N
T
E
N
A
N
C
E