Owner's manual

4
PREVENTIVE MAINTENANCE
Important: Review the Bendix Warranty Policy before
performing any intrusive maintenance procedures. A
warranty may be voided if intrusive maintenance is
performed during the warranty period.
No two vehicles operate under identical conditions, as
a result, maintenance intervals may vary. Experience is
a valuable guide in determining the best maintenance
interval for air brake system components. At a minimum,
the SV valves should be inspected every six (6) months
or 1500 operating hours, whichever comes • rst, for proper
operation. Should the SV valves not meet the elements
of the operational tests noted in this document, further
investigation and service of the valve may be required.
If the Bendix
®
SV-1
™
, SV-3
™
, or SV-4
™
valve fails to function
as described or leakage is excessive, it should be repaired
or replaced with a Genuine Bendix valve, available at any
authorized parts outlet.
OPERATING AND LEAKAGE TESTS
OPERATING TEST
Two accurate air gauges are necessary to perform these
tests. Depending upon installation, it may be necessary
to remove the valve to properly test it. Correct opening
pressures of the valve should be known before beginning
tests; consult the vehicle manual.
1. Install an accurate gauge in the common control and
supply line; install another gauge in the delivery port.
2. Gradually apply air pressure to the common supply and
control line. As common supply and control pressure
increases, note at what pressure delivery of air through
valve is made and compare with speci• cations in
vehicle manual.
3. Slowly decrease pressure in the common supply and
note at what pressure delivery line pressure is vented;
compare with vehicle manual.
4. Pay particular attention to the exhaust check valve in
the exhaust port if so equipped (see Figure 3). Make
certain it is free of contamination and the rubber valve
is free to function. Replace this item as necessary.
LEAKAGE TEST
1. With 120 psi air pressure present in supply, control and
delivery ports:
- Apply a soap solution around control port cap nut and
supply port cap nut. No leakage is permitted.
- Apply soap solution to the exhaust port; leakage must
not exceed a 1" bubble in less than 5 seconds (100
sccm).
Excessive leakage would indicate a faulty o-ring, inlet/
exhaust valve or piston exhaust seat.
2. Plug the delivery port and apply 10 psi to the supply
port only. Apply soap solution to the exhaust port:
- For the SV-1 valve - leakage must not exceed a 1"
bubble in less than 5 seconds (100 sccm).
- For the SV-3 & SV-4 valves - leakage must not exceed a
one (1) inch bubble in less than 10 seconds (50 sccm).
Excessive leakage would indicate a faulty inlet valve
or inlet valve seat.
If the valve does not function as described, or if leakage
is excessive, it is recommended that it be replaced with a
new unit, or repaired with Genuine Bendix parts available
at Bendix outlets.
REMOVING AND INSTALLING
REMOVING
1. Block and hold the vehicle by means other than air
brakes.
2. Drain the air brake system.
3. Identify the air lines to facilitate re-installation,
disconnect the lines, remove the mounting bolts, and
then the valve.
INSTALLING
1. Mount the valve securely.
2. Check and clean air lines; identify air lines and connect
to valve.
DISASSEMBLY
1. Remove the control port cap nut and its o-ring. Remove
the o-ring from the cap nut.
2. Remove the piston from the valve body. Remove the
large and small piston o-rings from the piston.
3. Remove the piston return spring from the body.
4. Remove the supply port cap nut and its o-ring. Remove
the o-ring from the cap nut.
5. Remove the inlet/exhaust valve stop (SV-1 valve) or
the spring guide (SV-3 & SV-4 valve), then the inlet/
exhaust valve spring.
Note: The SV-4 valve contains a check valve which is
installed in the opposite end of the inlet/exhaust valve
return spring.
6. Remove the inlet/exhaust valve.
7. Remove the exhaust check valve if so equipped.
CLEANING AND INSPECTION
1. Using good commercial grade of solvent, clean and
thoroughly dry all metal parts. Do not damage bores
with metal tools.
2. Inspect the interior and exterior of all metal parts that
will be reused for severe corrosion, pitting and cracks.
Super• cial corrosion and/or pitting on the exterior
portion of the body and cap nuts is acceptable. Replace
the entire valve if the interior of the body or cap nuts
exhibit signs of corrosion or pitting.
3. Inspect the body bore and the check valve seat in the
supply port cap nut of the SV-4 valve for deep scuf• ng
or gouges. Replace the entire valve if either are found.