Bendix Commercial Vehicle Systems EB/ES BRAKES SERVICE MANUAL - Manual (Page 17)

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3. Apply and hold an 80 psi brake application, and again measure
from face of air chamber to clevis pin centerline. Refer to Figure 9.
Record distance as dimension “B”. 5. Take “A” dimension exactly as before. Take “B” measurement
using a lever to move brake adjuster as shown until the shoes
contact drum. Refer to Figure 10. The result of “B” - “A” is brake
free stroke. Adjust free stroke to within range specifi ed in Table 3.
6. To adjust free stroke, depress locking sleeve on brake adjuster
adjustment nut and turn in direction required. Recheck free stroke
to verify it is within range. Make sure sleeve is “locked” when
adjustment is completed.
7. Verify that brakes are not dragging by spinning wheels by hand
or tapping drum lightly with a hammer and listening for a sharp
ringing sound.
8. Perform Brake Operation Check, to verify proper operation of
brakes before releasing vehicle for service.
Brake Adjustment - Automatic Slack Adjuster
NOTE: A properly working Automatic Slack Adjuster does not require
manual adjustment while in service. The manual adjuster hex is
intended for use during adjuster installation and brake overhaul.
WARNING: Automatic slack adjusters must never be repeatedly
adjusted to correct excessive in service pushrod stroke, because this
condition indicates that a problem exists with the automatic adjuster,
with the installation of the adjuster or with related foundation brake
components which manual adjustment will not correct.
1. Brake adjustment for automatic slack adjusters is the same as for
manual brake adjusters.
2. Refer to the Automatic Slack Adjuster Manufacturer's Instructions for
proper installation.
NOTE: If adjustment is necessary, Bendix Brakes are adjusted to
achieve proper free stroke. The difference between free stroke and
applied stroke is merely the method used to move the brake adjuster
from rest. Applied stroke uses an 80 psi brake application; free
stroke is measured using a lever to move the brake adjuster until the
brake shoes contact the drum. If applied stroke exceeded the
maximum and adjustment is necessary, adjust the brakes as
described in steps 5 through 8 below.
4. Subtract dimension “A” from “B”. The difference is applied stroke.
Compare applied stroke to maximum value in Table 3. If applied
stroke equals or exceeds maximum applied stroke shown, adjust
brakes. If less than the maximum, no adjustment is required and you
may perform Brake Operation Check.
Figure 9. Measurement, 80 psi Applied
Figure 10. Measurement, Brake Applied
80 - 90 PSI
Air Chamber Maximum Desired
Size Applied Free
Stroke Stroke
Type 30" Long Stroke 2.5" 3/8" to 5/8"
Type 30" 2" (Without Drag)
Type 24" 1-3/4"
Type 24" (w/ 2-1/2" 2"
extended stroke)
Type 24 (w/3" extended stroke) 2.5"
Type 20" and 16" 1-3/4" 3/8" to 1/2"
Type 12" 1-3/8" 3/8" to 1/2"
Maintenance and Adjustment
Table 3. Stroke Values
Periodic Service