5.1
Open the cover to the main power distri-
bution module (PDM).
5.2
Pull the fuse in position F6 for the Hydro-
Max relay.
5.3
Inspect the relay to make sure the fuse is
not damaged. If the fuse is damaged, in-
stall a new fuse. If the fuse is not dam-
aged, install the fuse in position F6.
5.4
Close the PDM cover.
6.
Check the operation of the Hydro-Max brake
booster, as follows.
6.1
With the engine off, depress the brake
pedal; the warning light and buzzer
should come on, and the electric motor
should run.
6.2
Start the engine and allow the gauges to
sweep. Depress the brake pedal; no
warning lights, buzzer, or electric motor
should come on.
42–15 WABCO System Saver
Air Dryer Desiccant
Cartridge Replacement
NOTE: The following instructions apply to the
System Saver 1200, 1200 Plus, and Twin air
dryers.
NOTICE
The WABCO System Saver air dryers can use ei-
ther a standard or oil coalescing desiccant car-
tridge. When replacing the desiccant cartridge, it
is very important to use the same type of car-
tridge that was originally installed on the dryer. Oil
coalescing cartridges can be used in any applica-
tion, but require more frequent service intervals
(every 1 to 2 years instead of every 2 to 3 years
for a standard cartridge). Do not replace an oil co-
alescing cartridge with a standard cartridge, as
this may result in contamination and malfunction-
ing of downstream air system components.
Refer to
for cartridge replacement.
1.
Drain the air system.
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.
42–16 Versajust Slack Adjuster
Inspection and
Lubrication
IMPORTANT: Perform the
Brake Inspection
maintenance operation before lubricating the
slack adjusters.
f4212
9
2
10/07/2016
1
2
3
1.
Seal
2.
O-Ring
3.
Air Dryer Base
Fig. 11, Desiccant Cartridge Replacement
Brakes
42
Business Class M2 Maintenance Manual, November 2015
42/15
Property of American Airlines
