Technical Bulletin
Bulletin No: TCH-013-017 Effective Date: 7/30/08 Cancels: N/A Page: 1 of 2
Subject: Protect Your Bendix
®
ATR-1
™
, ATR-2
™
and R-14
®
Relay Valves from
De-icing Chemicals
Vehicles exposed to harsh winters, de-icing and/or
other chemical sprays, often experience excessive
corrosion and contamination. As a result, these
vehicles typically need maintenance more often,
and vehicle parts exposed to de-icing chemicals
tend to require replacement sooner. For air system
components, one potential result of exposure to
corrosion and contamination can be restricted or
blocked exhaust ports which can reduce air system
performance.
Regular maintenance routines typically include in-
spections for corrosion and contamination. Air control
valves with smaller secondary exhaust ports, such as
the Bendix®ATR-1™orATR-2™traction control valves
and R-14®relay valves (See Figure 1), are especially
important to check. These valves are often situated
in difficult-to-reach locations on the vehicle, however,
by following the steps outlined in this Bulletin, the
technician can verify that the valves are functioning
correctly.
Bendix recommends that potentially affected
vehicles:
• Use the specific test(s) below to determine if the
valves are functioning properly
• Install air system components in areas protected
fromdirect splashand roadspray, andinstall splash
guards where necessary
• Have more frequent inspection and maintenance
schedules in regions that have greater exposure
to de-icing chemicals
Early indications that maintenance is required include
reports of “brake drag” — that service brakes appear
to be slow to release following a braking or traction
control event.
When conducting the following Tests, follow all industry
standard safety guidelines, including, but not limited to,
those shown on page two of this Bulletin.
In all cases, consult your vehicle manufacturer’s
servicemanualfordetails of any further teststhatthey
recommend.
To Test ATR-1™and ATR-2™Traction Relay
Valves:
The antilock traction control (ATC) system is tested
by connecting the vehicle to a PC with the Bendix®
FIGURE 1 - EXAMPLES OF R-14®RELAY VALVE AND
ATR-1™AND ATR-2™TRACTION RELAY VALVES
ACom™diagnostics program loaded. (ACom™
software is available as a free download from www.
bendix.com). Run the ATC Valve Test provided in
ACom™diagnostics,andverify thatthebrakes arefully
releasing after the ATC event. If the brakes are slow
to release, replace the traction relay valve and repeat
the above check.
To Test R-14®Relay Valves:
Visually inspect (where possible) that the balance
exhaust port cover is present on the relay valve; in
cases where the cover is missing, replace the entire
valve with a new valve. During installation, confirm
that the exhaust cover is firmly attached.
If the cover is present, verify that the R-14®relay valve
used is functioning properly by fully charging the air
systemand blockand holdvehicle bymeans otherthan
the air brakes. Then make several brake applications
and check for prompt application and release of each
wheel’s brakes with no perceptible lag.
Ifthe brakesare slowto release,replace therelayvalve
and repeat the above test. If the brakes continue to
exhibitslowrelease,refertothetroubleshootingsection
in your vehicle manufacturer’s service manual.
R-14®Relay Valve
Cover for Balance/
Quick Exhaust Port
(Used for Anti-
Compound Functions)
Relay Valve Exhaust Port
Secondary Exhaust Ports (With Cover) are
Located Behind the Mounting Bracket
Relay Valve Exhaust Port
