42–21 Sealco Moisture Ejection
Valve Operation- and
Leak-Testing (Model
6300)
Operation-Testing
WARNING
Keep away from the front of the moisture ejection
valve exhaust outlet because moisture, scale, or
other debris will be ejected with force when the
compressor is cycled. Use eye protection such as
safety glasses when checking the moisture ejec-
tion valve to prevent harm to your eyes from fly-
ing debris.
When the moisture ejection valve is plumbed to the
governor unloader, an exhaust of air/sludge will occur
only when the air compressor starts or stops pump-
ing air. With the air system charged, cycle the brake
foot valve until the air compressor starts pumping air.
Notice if an exhaust of air/sludge occurs at the ex-
haust outlet of the moisture ejection valve (
Fig. 11
)
when the air compressor starts pumping (cuts in) or
stops pumping (cuts out).
If there is no discharge, repair or replace the mois-
ture ejection valve; for instructions, see Group 42 of
the
Heavy-Duty Trucks Service Manual
.
Check the valve again for operation. Repeat the in-
structions under this heading until the valve operates
as specified. If the valve fails to operate properly,
install a new one.
Leak-Testing
For leak-testing instructions, see Group 42 of the
Heavy-Duty Trucks Service Manual
.
42–22 Midland Quick Release
and Flipper Valve
Checking
1.
Chock the tires.
2.
Start the engine and run it long enough to pres-
surize the air system to at least 80 psi (550 kPa),
then turn off the engine. Repeat as needed, to
maintain 80 psi (550 kPa) pressure during these
checks.
3.
Clean off road grime from the valves, and any
material from all valve exhaust ports.
4.
Listen for air leakage around fittings and exhaust
ports. Tighten the fittings as needed; use two
wrenches to avoid twisting the tubing.
If any valve fails this check, or is damaged, re-
pair or replace it. Refer to the Midland service
manual for instructions.
5.
Remove the chocks from the tires.
42–23 Meritor WABCO System
Saver 1000 Air Dryer
Desiccant Replacing
Replace the desiccant cartridge. For instructions, see
Group 42 of the
Heavy-Duty Trucks Service Manual
.
NOTE: Desiccant change intervals may vary
from vehicle to vehicle. Typical desiccant car-
tridge life is three years. However, if experience
has shown that extended or shortened life has
f420007a
1
2
3
4
5
6
7
05/28/93
1.
Reservoir Inlet
2.
Upper Cap
3.
Guide Post
4.
Column
5.
Body Casting
6.
Application Line
7.
Exhaust Outlet
Fig. 11, Sealco 6300 Moisture Ejection Valve
Brakes
42
42/13