Installation - BENDIX AD-9 Service Data

4. Install the end cover outer housing o-ring (23) on the
shoulder in the end cover. Place the housing (24) over
the desiccant cartridge and align the holes. Install the
six 3/8" cap screws (16), lock nuts (19) and twelve special
washers (17) making certain they are in the proper
position as marked during disassembly. The two longer
3/8" cap screws (18) will be used to secure the AD-9 to
its mounting bracket. Tighten the six cap screws and
nuts in a star pattern in a fashion similar to Figure 8;
depending on lower bracket location. Torque to 270-385
in. Ibs. (Refer to Fig. 8.) Note: The two remaining bolt
holes in the end cover and two 3/8" cap screws must be
the ones marked during disassembly to assure proper
orientation of the ports and adequate length of the cap
screws.

INSTALLATION

1. Install the assembled AD-9 air dryer back onto the vehicle
by slipping it into the upper mounting bracket. Align the
two unused holes in the end cover with the bottom
mounting bracket such that the bottom bracket supports
air dryer. The AD-9 end cover should rest on the bracket.
Using the remaining two 3/8" cap screws (18), four special
washers (17), and two lock nuts (19), secure the air
dryer to the lower bracket. Tighten, then torque the two
remaining cap screws to 270-385 in. Ibs.
2. Tighten the 5/16" X 4-1/2" bolt and nut on the upper
mounting bracket. Torque to 80-120 in Ibs.
3. Reconnect the three airlines to the proper ports on the
end cover (identified during disassembly).
4. Reconnect the vehicle wiring harness to the AD-9 heater
and thermostat assembly connector by plugging it into
the air dryer connector until its lock tab snaps in place.
5. Before placing vehicle back into service, perform the
Operation and Leakage Tests stated elsewhere in this
manual.
RETROFITTING THE AD-9 AIR DRYER
GENERAL
The following retrofit instructions are presented for reference
purposes only since Bendix aftermarket retrofit and
replacement air dryers are packaged with the most up-to-
date installation instructions. The instructions packaged with
the AD-9 should be followed in lieu of those presented here.
The preceding portion of this manual deals with “in-service”
repair and or replacement of the AD-9 air dryer. The portion
of the manual that follows is concerned with installing an
AD-9 on a vehicle not previously equipped with one.
VEHICLE APPLICATION REQUIREMENTS
The basic application requirements presented here apply to
a standard air dryer installation. The majority of highway
vehicles in use today will meet these basic requirements
10
however, some may not. Examples of vehicles that may not
meet the requirements include, bulk trailer unloading
operations and other high air consumption/continuous flow
systems. While the AD-9 air dryer can be used on these
vehicles the standard installation procedure presented in
this manual may require modification to assure proper
operation and service life. Consult your local authorized
Bendix parts outlet or sales representative for additional
information.
1. Charge Cycle Time - The AD-9 air dryer is designed to
provide clean, dry air for the brake system. When a
vehicle’s air system is used to operate non-brake air
accessories it is necessary to determine that during
normal, daily operation the compressor should recover
from governor “cut-in” to governor “cut-out” (usually 100
psi to 120 psi) in 90 seconds or less at engine RPMs
commensurate with the vehicle vocation. If the recovery
time consistently exceeds this limit, it may be
necessary to “bypass” the air accessory responsible for
the high air usage. Consult your local authorized Bendix
parts outlet or sales representative for additional
information.
2. Purge Cycle Time - During normal vehicle operation, the
air compressor must remain unloaded for a minimum
of 20 seconds for the standard AD-9 Air Dryer or 30
seconds for the Extended Purge model. These
minimum purge times are required to ensure complete
regeneration of the desiccant material. If the purge time
is occasionally shorter than the times specified, no
permanent ill effect should be expected, however, if the
purge time is consistently less than the minimum, an
accessory by-pass system must be installed.
3. European Air Brake Systems - Brake systems that
incorporate compressors without integral unloading
mechanisms and/or utilize a compressor discharge line
unloader valve have special AD-9 air dryer installation
requirements. Consult your local authorized Bendix parts
outlet or sales representative for additional information.
4. Air Compressor Size - Although the AD-9 air dryer can
be used in conjunction with larger compressors, it was
designed primarily for units rated for up to 17 CFM. It is
recommended that when using the AD-9 air dryer with a
compressor which has a rated displacement exceeding
17 CFM that an authorized Bendix parts outlet or Bendix
marketing representative be contacted for assistance.
5. Holset “E or QE” Type Air Compressors - In order for the
AD-9 to function properly when installed with the Holset
Type “E or QE” compressor, several specialized Holset
components are required. Consult your local authorized
Holset parts outlet or sales representative for additional
information.
6. Use of Standard or Extended Purge AD-9 - Use the
following guidelines: