BENDIX TCH-008-041 ユーザーズマニュアル
Technical
Bulletin
Bulletin No:
Effective Date:
Cancels:
Page: 1 of
Subject:
© 2006 Bendix Commercial Vehicle Systems LLC All rights reserved. 6/2006 Printed in U.S.A.
TCH-008-041
6-20-2006
N/A
3
Bendix
®
AD-9
™
Air Dryer Purge Valve Identifi cation & Kits
The Bendix
®
AD-9
™
air dryers are available with various purge valve confi gurations; hard seat, soft seat
and DLU discharge line unloader types. The difference between these types relates to the type of sealing
surface for the turbo cut-off valve. All AD-9
surface for the turbo cut-off valve. All AD-9
™
air dryers contain two valve sections and have a rubber (soft)
seat for the actual purge valve, but the turbo cut-off valve section can be one of three types:
1. Hard seat purge valve has a metal to metal turbo cut-off valve sealing surface. Most AD-9
™
air dryers
come standard with the hard seat purge valve.
2. Soft seat purge valve has a bonded rubber ring on the piston that contacts a metal seat on the housing
to make the turbo cut-off valve seal. This seal is extremely air tight for applications that require zero
leakage, such as the Bendix
leakage, such as the Bendix
®
EverFlow
™
system and drop-in style air dryers which use older Holset
type E compressors.
3. Discharge line unloading (DLU) purge valve has the turbo cut-off valve bypassed by removing the
middle o-ring sealing surface from the body. This valve is used to positively vent the compressor
discharge line, such as when the vehicle has a non-unloading compressor.
discharge line, such as when the vehicle has a non-unloading compressor.
NOTE: Although a soft seat purge valve can be substituted for a hard seat purge valve, a hard seat purge
valve should not be substituted for a soft seat purge valve. DLU purge valves cannot be substituted for any
other type.
valve should not be substituted for a soft seat purge valve. DLU purge valves cannot be substituted for any
other type.
Figure 1 - Identifi cation of Hard and Soft Seat Purge Valves
Hard Seat
Soft Seat
Metal
Black
Rubber