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Freightliner Business Class M2. Manual - part 24

14. Place the desiccant cartridge in a vise, and turn

the end cover clockwise an additional 180 to 225
degrees to fully tighten the desiccant cartridge to
the end cover.

NOTE: Desiccant cartridge torque should not
exceed 50 lbf·ft (68 N·m).

15. Place the housing over the desiccant cartridge

and align the mounting holes with the end cover.

IMPORTANT: Replace, do not reuse the Nylok
nuts on the air dryer cover.

16. Install the 6 bolts, 12 washers, and 6 new Nylok

nuts. Torque the Nylok nuts in a star pattern 17
to 24 lbf·ft (23 to 33 N·m). See

Fig. 2

17. Install the air dryer on the lower mounting

bracket. Install the two previously marked bolts,
four washers, and two new Nylok nuts. Torque
the two remaining Nylok nuts 17 to 24 lbf·ft (23

08/09/95

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7
8

5/16 x 4-1/2 Upper Mounting
Bracket Bolt

Upper Mounting Bracket Strap

Lockwasher

5/16-Inch Nylok Nut

Upper Mounting Bracket

Housing

Nylok Nut

3/8-Inch Special Washer

Desiccant Cartridge

10. O-Ring
11. Safety Valve
12. Lower Mounting Bracket
13. 3/8-Inch Bolt (long)
14. Check Valve Assembly
15. Purge Valve Assembly
16. Purge Valve Capscrew
17. Exhaust Diaphragm

18. Purge Valve
19. 1/4-Inch Tapping Screw
20. Purge Valve Housing
21. Heater and Thermostat

Housing

22. Return Spring
23. Purge Piston
24. 3/8-Inch Bolt
25. End Cover

Fig. 1, AD–9 Air Dryer (exploded view)

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to 33 N·m). Install the bolt, two washers, and a
new Nylok nut in the upper mounting bracket
strap. Torque the upper mounting bracket strap
Nylok nut 80 to 120 lbf·in (900 to 1360 N·cm).

18. Connect and tighten the three air lines. Connect

the harness connector to the heater and thermo-
stat assembly until the lock tab snaps in place.

19. Start the engine, build the air pressure, and

check the air brake system for leaks. If any air
leaks are present, see Group 42 of the vehicle
Workshop Manual for diagnosis and repair
information.

AD–IP

Park the vehicle on a level surface, apply the
parking brakes, and chock the tires.

Using a wrench or a socket, loosen the desiccant
cartridge bolt. Then separate the desiccant car-
tridge from the end cover.

Pull the cartridge bolt out of the cover and re-
move the cartridge.

WARNING

Do not attempt to disassemble the desiccant car-
tridge assembly. Parts for the assembly are not
available and the cartridge contains a 150 lb

spring that cannot be mechanically caged. Disas-
sembly could release the spring, resulting in per-
sonal injury.

Remove and discard both O-rings from the car-
tridge bolt.

Using a clean rag, wipe clean the inside of the
end cover. Clean the cartridge bolt bore in the
end cover, and the sealing surfaces for the large-
and small-diameter desiccant cartridge sealing
rings.

Inspect the end cover for physical damage, then
inspect all air line fittings for corrosion; replace
as necessary.

Clean and inspect the bolt, paying attention to
the threads and O-ring grooves.

IMPORTANT: Use only the grease supplied with
Bendix replacement kits.

Lubricate the O-rings, bolt O-ring grooves, seal-
ing rings, and cartridge grooves. Lubricate the
end cover bore for the bolt.

Install both O-rings on the cartridge bolt, then,
using a twisting motion, insert the assembled
desiccant cartridge bolt in the end cover.

10. Install the desiccant cartridge on the end cover,

making sure the cartridge is properly seated and
flush on the end cover.

NOTE: It may be necessary to rotate the car-
tridge slightly until the anti-rotation lugs are
properly aligned and allow the cartridge to rest
flush against the end cover.

11. Using a wrench or socket, tighten the desiccant

cartridge bolt 70 lbf·ft (95 N·m). Do not over-
torque.

12. Before placing the vehicle in service, perform the

test below.

12.1

Close all reservoir drain cocks.

12.2

Build system pressure to governor cut-
out, and note that the AD-IP air dryer
purges with an audible escape of air.

12.3

Fan the service brakes to reduce system
air pressure to governor cut-in. Note that
the system once again builds to full pres-
sure and is followed by a purge at the
AD-IP air dryer exhaust.

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09/20/94

Fig. 2, AD–9 End Cover to Housing Torque Pattern

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12.4

Check for excessive leakage around the
head of the desiccant cartridge where it
contacts the end cover. With the com-
pressor in loaded mode (compressing
air), apply a soapy solution to these
areas, and observe that any leakage
does not exceed a 1-inch bubble in 1
second. If leakage exceeds this measure,
remove and re-install the desiccant
cartridge.

AD-9si and AD–IS

Park the vehicle on a level surface, apply the
parking brakes, and chock the tires.

Drain the air reservoirs.

Using a strap wrench or equivalent, loosen the
desiccant cartridge. Spin the cartridge off by
hand and discard it. See

Fig. 3

On the new desiccant cartridge, lubricate the
sealing rings with silicone grease.

IMPORTANT: Only use the silicone grease sup-
plied with Bendix replacement kits.

Screw the desiccant cartridge onto the body by
hand until the seal makes contact with the body.
Rotate the cartridge clockwise about one full
turn. Tighten the cartridge firmly.

42–03 Governor D–2A Check

IMPORTANT: Review the warranty policy before
performing any intrusive maintenance proce-
dures. An extended warranty may be voided if
intrusive maintenance is performed during this
period.

Every 12 months, 100,000 miles (160 900 km), or
3600 operating hours, perform the operational test
below.

Operational Test

Start the vehicle engine, build air pressure in the
brake system, and check the pressure registered
by a dash or test gauge at the time the governor
cuts-out, stopping the compression of air by the
compressor. Cut-out pressure should be in ac-
cordance with the pressure setting of the piece
number being used. Common cut-out pressures
are 125 to 135 psi (862 to 931 kPa). With the
engine still running, make a series of brake appli-
cations to reduce the air pressure, and observe
at what pressure the governor cuts-in the com-
pressor. As in the case of cut-out pressure, cut-in
pressure should be in accordance with the pres-
sure setting of the piece number being used.
Cut-in pressure is 105 psi (724 kPa).

NOTE: If the governor cover is marked nonad-
justable, and the adjusting stem has been
sheared off, this is a non-serviceable governor
and it must be replaced with a new or remanu-
factured unit.

Never condemn or adjust the governor pressure
settings unless they’re checked with an accurate
test gauge or a dash gauge that’s registering ac-
curately. If the pressure settings of the D-2 gov-
ernor are inaccurate or it’s necessary that they
be changed, the adjustment procedure follows.

2.1

Remove the top cover from the governor.

2.2

Loosen the adjusting screw locknut.

2.3

To raise the pressure setting, turn the ad-
justing screw counterclockwise; to lower
the setting, turn the screw clockwise. Be
careful not to overadjust. Each 1/4 turn of
the adjusting screw raises or lowers the
pressure setting approximately 4 psi (28
kPa).

04/16/98

f421910

Desiccant Cartridge

Cartridge Sealing Ring

Threaded Base Post

Fig. 3, Desiccant Cartridge Replacement

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2.4

When proper adjustment is obtained,
tighten the adjusting screw locknut, and
install the top cover. The pressure range
between cut-in and cut-out is not adjust-
able.

Cut-In Position

Apply soap solution around the cover and to the ex-
haust port. Slight bubble leakage is permitted. Exces-
sive leakage indicates a faulty inlet valve or faulty
lower piston O-ring.

Cut-Out Position

Apply soap solution around the cover and to the ex-
haust port. Slight bubble leakage is permitted. Exces-
sive leakage indicates a faulty exhaust valve seat,
exhaust stem O-ring, or O-ring at the top of the
piston.

If the governor does not function as described, or if
leakage is excessive, it is recommended that it be
replaced with a new or remanufactured unit, or re-
paired with genuine Bendix parts.

42–04 Bosch Hydraulic Brake

System Inspection

Before checking lining wear with the wheel removed,
review the following brake lining exposure warnings.

WARNING

Breathing brake lining dust (asbestos or non-
asbestos) could cause lung cancer or lung dis-
ease. Unless exposure can be reduced below legal
limits, wear an air purifying respirator approved
by MSHA or NIOSH at all times when servicing the
brakes, starting with removal of the wheels and
continuing through assembly.

To minimize the possibility of creating airborne brake
lining dust, clean the dust from the brake rotor, brake
caliper, and brake assembly, using an industrial-type
vacuum cleaner equipped with a high-efficiency filter
system. Then, using a rag soaked in water and
wrung until nearly dry, remove any remaining dust.
Do not use compressed air or dry brushing to clean
the brake assembly.

Check lining wear, as follows.

1.1

Apply the parking brakes. Chock the tires
to prevent vehicle movement.

1.2

Remove one or more of the lining inspec-
tion plugs, and measure brake lining
thickness.

1.3

On front and rear axles, replace linings
worn to less than 1/16 inch (1.6 mm).

1.4

Make sure that the brake rotor and linings
are free of oil and grease.

1.5

Install the inspection plug(s).

If the wheel and hub assembly is removed from
the axle, check lining wear. Replace the linings
on all brake assemblies if worn to less than 1/16
inch (1.6 mm) at the thinnest point. Check the
brake pads for wear and replace, as necessary.

42–05 Dana Spicer, Haldex,

and Gunite Slack
Adjuster Lubrication

IMPORTANT: Perform a brake inspection before
lubricating the camshaft bracket.

Automatic slack adjusters that have a grease fitting
must be lubricated periodically to ensure proper
brake operation.

WARNING

Failure to lubricate slack adjusters could lead to
dragging brakes or a brake failure, resulting in
property damage, personal injury, or death.

Dana Spicer and Haldex

WARNING

Do not use moly-disulfide-loaded grease or oil.
Both the life and reliability of the slack adjuster
will be reduced if this type of grease is used,
which could lead to brake failure, resulting in
property damage, personal injury, or death.

Lubricate the automatic slack adjuster at the grease
fitting. See

Fig. 4

for a Dana Spicer slack adjuster.

Dana Spicer Low Lube slack adjusters should be lu-
bricated with SHC 460 synthetic lubricant. See

Fig. 5

Brakes

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