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®
RESERVOIRS
SD-04-400
It should be drained off either manually or by means of an
automatic drain device.
OPERATION OF INTEGRAL CHECK VALVE
The integral check valve provides a one-way passage of
air from the upstream compartment to the downstream.
TYPICAL SINGLE COMP ARTMENT RESER VOIR
DESCRIPTION
The reservoir is a storage tank; its function is to provide a
volume of compressed air for braking which will be adequate
in relation to the volume used by the brake chambers and
auxiliary devices. Reservoirs also provide a location in the
system where the air, heated by compression, may be cooled
and the water vapor condensed.
Bendix® reservoirs are built in accordance with SAE Standard
Air Brake Reservoir Test Code and Inspection Procedure
SAE J-10-a. They are made from steel sheet, with stamped
heads and rolled shells. The seams are electrically welded,
and each reservoir is internally coated for corrosion resistance.
Each reservoir is tested at 300 PSI hydrostatic pressure.
Reservoirs are supplied in various pipe ferrule arrangements
and lengths and in diameters from 3-1/2" to 14" having
various volumes from approximately 100 cubic inches to
7600 cubic inches for tractors and trailers. All ferrules are
tapped to SAE dryseal pipe thread standards.
Reservoirs are also supplied in double and triple compartment
configurations and in some cases include an integral check
valve between compartments in a double compartment
reservoir. Figure 1 illustrates a two comp artment reservoir.
Two styles of check valves are shown in Figures 2 and 3.
Figure 3 is the current design.
OPERATION
The reservoirs in an air brake system primarily serve to store
energy in the form of compressed air. They also perform the
less obvious function of providing a means of cooling the air
as delivered from the compressor and thereby condensing
water vapor into a liquid as well as collecting oil passed by
the compressor. This water and oil collects as an emulsion;
the greatest amount in the reservoir nearest the compressor.
This check valve may serve to meet the legal requirement
for a check valve to protect the service brake system in
case of failure in the compressor, discharge lines or first
reservoir compartment.
PREVENTIVE MAINTENANCE
All reservoirs should be drained daily . If an automatic drain
device is used, it should be checked periodically for proper
functioning. If an air dryer or aftercooler is used, the
reservoirs should be manually drained periodically to verify
the proper function of the drying device. Reservoirs, which
have collected a considerable oily emulsion, should be
drained by opening a drain cock and allow to drain until all
drainage stops.
MAINTENANCE OF THE INTEGRAL CHECK
VALVE
Every six months, 1,800 operating hours or 50,000 miles
the check valve on the two compartment reservoir should
be tested for leakage, as outlined below, and p arts inspected
for damage or deterioration and replaced if considered
unserviceable.
OPERATING AND LEAKAGE TEST FOR TWO
COMP ARTMENT RESERVOIR CHECK V ALVE
1. Determine the direction of the air flow.
2. Build up system air pressure to governor cut-out and
turn off engine.
3. Completely drain compartment #1 (see Figure 1).
NOTE: It may be necessary to remove automatic drain
device if so equipped.
4. To determine pressure retention in #2 compartment,
perform one of the following tests:
a. Check dash gauge (if connected to #2 compartment).
b. Apply service brake (if supplied from #2
compartment).
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FIGURE 3 FIGURE 2
SERVICE EACH 50,000 MILES
OR EVERY 6 MONTHS WITH:
FIELD MAINTENANCE KIT 282350
CONSISTING OF:
1 - CHECK VALVE
1 - GUIDE
1 - SPRING
1 - O-RING
COMPARTMENT 1 COMPARTMENT 2
CAP NUT
GROOVE IN
CAP NUT
O-RING
VALVE
SPRING
GUIDE
CHECK
VALVE
CAP NUT
VALVE
SPRING
O-RING
SEAT SPRING
CHECK VALVE
O-RING
SEAT
FIGURE 1 - TWO COMPAR TMENT RESERVOIR WITH CHECK V AL VE
c. Momentarily open drain device on # 2 compartment.
Do not completely drain #2 Compartment.
5. Apply a soap solution to the drain ferrule #1
compartment. A slight bubble leakage is permitted.
If #2 compartment fails to hold air pressure or if excessive
leakage is evident at the drain ferrule of #1 compartment,
the check valve should be inspected for serviceability and
nut and cap nut o-ring. Remove check valve and check valve
spring. Remove seat spring. With a hook or similar device,
carefully remove the check valve seat and its
o-ring so as not to mar or scratch it.
DISASSEMBL Y OF THE FLAT STYLE CHECK
VALVE (FIGURE 3)
Block and hold vehicle by means other than air brakes.
its parts replaced if necessary.
Completely drain compartments #1 and #2.
DISASSEMBLY
GENERAL
There are two types of two-compartment reservoir check
valves and they are;
1. The old ball style check with a removable seat and a
seat spring (see Figure 2).
2. The new flat style that has a non-removable stainless
steel seat (see Figure 3).
Both types of check valves are located in a housing (large
ferrule) with a cap nut cover. They are generally located on
top of the reservoir shell.
Remove cap nut and cap nut o-ring.
Remove valve spring.
Remove valve and valve guide.
CLEANING AND INSPECTION
Wash all metal parts in a good cleaning solvent and dry
them thoroughly. All rubber parts should be wiped clean.
Inspect springs for distortion, corrosion, and cracks. Inspect
valves and valve seats for nicks, cuts and burrs. Inspect all
rubber parts for swelling and deterioration. Replace or repair
as necessary .
DISASSEMBL Y OF THE BALL STYLE CHECK
V A LVE (FIGURE 2)
Block and hold vehicle by means other than air brakes.
Completely drain compartments #1 and #2. Remove cap
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ASSEMBLY
GENERAL
Before assembly , the o-rings should be coated with silicone
lubricant BW-650-M Bendix pc. number 291126.
ASSEMBL Y OF THE BALL STYLE CHECK V AL VE
Replace seat o-ring and press seat into shell. Replace seat
spring. Install check valve and valve spring. Replace o-ring
on cap nut and install and tighten cap nut.
ASSEMBL Y OF THE FLA T STYLE CHECK V AL VE.
Replace valve guide on valve and install valve.
Install valve spring.
Replace o-ring on cap nut and install and tighten cap nut.
TEST
Perform tests as outlined in “Operation and Leakage Test”
section.
INST ALLATION
Reservoirs should be securely mounted where they will be
protected against outside damage and so they will not
vibrate or move during normal operation of the vehicle. A
vibrating reservoir usually causes broken tubing lines.
They should be the low point in the air brake system and all
lines connected to them should drain toward the reservoir.
The pipe tapped openings in the reservoir should not under
any circumstances be reduced in size from original
installation.
A drain cock or draining device must be installed in the
bottom connection of every reservoir and, in the case of
the two-compartment reservoir , in each compartment.
The first reservoir or first compartment must be protected
by installing a safety valve.
MINOR REP AIRS
Minor repairs to the reservoir consist of examining the
reservoir mounting and the inspection of the outside for
corrosion or damage. The outside should be kept painted
to prevent the possibility of corrosion causing a failure.
MAJOR REP AIRS
Repairs involving welding should never be performed on
reservoirs. If a reservoir has been damaged so as to be
unfit for use, it should be replaced with a new one.
In exceptional cases where the inside of a reservoir has
become excessively coated with sludge which cannot be
drained off, it is sometimes advisable to remove it and clean
with a solvent, steam, or water. If a solvent is used to clean
the reservoir, the reservoir should be thoroughly aerated before
reinstalling.
WARNING! PLEASE READ AND FOLLOW
THESE INSTRUCTIONS TO AVOID
PERSONAL INJURY OR DEATH:
When working on or around a vehicle, the following
general precautions should be observed at all times.
1. Park the vehicle on a level surface, apply the
parking brakes, and always block the wheels.
Always wear safety glasses.
2. Stop the engine and remove ignition key when
working under or around the vehicle. When
working in the engine compartment, the engine
should be shut off and the ignition key should be
removed. Where circumstances require that the
engine be in operation,
be used to prevent personal injury resulting from
contact with moving, rotating, leaking, heated or
electrically charged components.
3. Do not attempt to install, remove, disassemble or
assemble a component until you have read and
thoroughly understand the recommended
procedures. Use only the proper tools and observe
all precautions pertaining to use of those tools.
4. If the work is being performed on the vehicle’s air
brake system, or any auxiliary pressurized air
systems, make certain to drain the air pressure
from all reservoirs before beginning ANY work on
the vehicle. If the vehicle is equipped with an
AD-IS™ air dryer system or a dryer reservoir module,
be sure to drain the purge reservoir.
5. Following the vehicle manufacturer’s
recommended procedures, deactivate the electrical
system in a manner that safely removes all electrical
power from the vehicle.
6. Never exceed manufacturer’s recommended
pressures.
7. Never connect or disconnect a hose or line
containing pressure; it may whip. Never remove a
component or plug unless you are certain all
system pressure has been depleted.
8. Use only genuine Bendix® replacement parts,
components and kits. Replacement hardware,
tubing, hose, fittings, etc. must be of equivalent
size, type and strength as original equipment and
be designed specifically for such applications and
systems.
9. Components with stripped threads or damaged
parts should be replaced rather than repaired. Do
not attempt repairs requiring machining or welding
unless specifically stated and approved by the
vehicle and component manufacturer.
10. Prior to returning the vehicle to service, make
certain all components and systems are restored to
their proper operating condition.
11. For vehicles with Antilock Traction Control (ATC),
the ATC function must be disabled (ATC indicator
lamp should be ON) prior to performing any vehicle
maintenance where one or more wheels on a
drive axle are lifted off the ground and moving.
EXTREME CAUTION should
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BW1590 © 2004 Bendix Commercial Vehicle Systems LLC All rights reserved. 8/2004 Printed in U.S.A.
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