freightliner 108SD 2021, Driver Manual

Page: 137 / 191

2. Using a strap wrench, turn the desiccant car-
tridge counterclockwise and remove it.
3. Remove and discard the O-ring.
4. Clean the top surface of the dryer base with a
commercial cleaning solvent.
IMPORTANT: If the air dryer base is damaged,
preventing a tight seal, replace the air dryer.
5. Using a multipurpose, high-temperature grease
that resists water, steam, and alkali, lightly coat
the surfaces of the new O-ring and the dryer
base. Install the O-ring.
6. Thread the desiccant cartridge onto the dryer
base (turn clockwise). When the seal contacts
the base, tighten the cartridge one complete turn
more. Do not overtighten.
42–11 Versajust Slack Adjuster
Inspection and
Lubrication
IMPORTANT: Perform the Brake Inspection
maintenance operation before lubricating the
slack adjusters.
1. Visually check for physical damage, such as bro-
ken air lines and broken or missing parts.
2. Using a quality multipurpose chassis lubricant,
NLGI Grade 2, lubricate the slack adjuster
through the grease fitting until clean lubricant
flows from the grease relief opening in the boot.
3. Perform the "In Service Inspection."
In Service Inspection
1. Apply and release the brakes several times while
observing the slack adjuster. The slack adjuster
and brake actuator should move freely, without
binding or interference, and should return to the
full released position. Observe the looseness that
exists between the clevis and adapter bushing
and the yoke and link pins and their mating parts
(clevis, body, link). Replace these parts if loose-
ness appears excessive. Make certain the brake
actuator pushrod jam nut is tightened securely.
2. Inspect the slack adjuster for physical damage,
paying attention to the link, boot, and clevis. If
any components are damaged, repair or replace
them as necessary.
3. Measure the brake actuator pushrod stroke while
making an 80 to 90 psi (552 to 621 kPa) brake
application. Actuator pushrod strokes should not
exceed the values shown in
Table 3 and
Table 4 . To achieve the correct pressure for this
test, build the system pressure up to a 100 psi
(690 kPa). Shut down the engine. Fan the
brakes to attain a 90 to 95 psi (621 to 655 kPa)
reading. Make and hold a full brake application
while the strokes are checked.
Actuator Stroke–Standard Stroke
Brake Actuator Size
Recommended Maximum
Operating Stroke (Inches)
30 2
24 1-3/4
20 1-3/4
16 1-3/4
12 1-3/8
Table 3, Actuator Stroke–Standard Stroke
Actuator Stroke–Long Stroke
Brake Actuator Size
Recommended Maximum
Operating Stroke (Inches)
30 Long Stroke 2-1/2
24 Long 2
24 Long Stroke 2-1/2
20 Long 2
16 Long 2
Table 4, Actuator Stroke–Long Stroke
42–12 Bendix Automatic Drain
Valve Operating and
Leakage Tests
Operating Test
Perform the following test after repairing or replacing
the DV-2 valve, to ensure that the valve is function-
ing properly.
With the system charged, apply the brakes several
times. Each time the brakes are applied, an exhaust
Brakes
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108SD and 114SD Maintenance Manual, October 2019
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