3
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 limiting,
quick release, and TW-1
™
valves should be inspected every
12 months or 3600 operating hours, whichever comes first,
for proper operation. Should the limiting, quick release, and
TW-1
™
valves not meet the elements of the operational tests
noted in this document, further investigation and service of
the valve may be required.
OPERATING AND LEAKAGE TESTS
OPERATING TEST
For this check, two accurate test gauges will be needed.
Install one gauge in a brake chamber delivery line, and the
other in the foot valve delivery line.
1. Place the control valve in the “Dry Road” position and
make a foot valve application. Readings on both gauges
should be the same.
Release the application and note that air is exhausted
promptly from the exhaust port of the limiting and quick
release valve.
2. Place the control valve in the “Slippery Road” position
and apply the foot valve. The pressure reading on the
gauge in the brake chamber line should be 50% of the
reading of the gauge in the foot valve delivery line.
LEAKAGE TEST
1. Place the control valve in the “Dry Road” position. Make
and hold a foot valve application. Coat the exhaust of
the limiting and quick release valve with soap suds;
leakage should not exceed a 1" bubble in 3 seconds.
2. Place the control valve in the “Slippery Road” position.
Make and hold a foot valve application. Coat the exhaust
of the TW-1
™
control valve; leakage should not exceed a
1" bubble in 3 seconds.
If the valve does not function as described above, or if
leakage is excessive, it is recommended that the valve be
replaced with a new or remanufactured unit, or repaired
with genuine Bendix parts.
REMOVING AND INSTALLING
Block and hold vehicle by means other than air brakes.
LIMITING & QUICK RELEASE VALVE
Identify all lines to facilitate installation; disconnect lines
and remove valve.
TW-1
™
CONTROL VALVE
1. Identify lines to facilitate installation.
2. Disconnect lines.
3. Remove two screws on valve dial plate.
4. Remove dial plate
5. Remove valve.
INSTALLING
LIMITING AND QUICK RELEASE VALVE
1. Locate valve near front axle in close proximity to the
chambers it serves.
2. Install valve with exhaust port, pointing down. Use two
mounting bolts and tighten securely.
3. Connect brake chamber lines to delivery ports.
4. Connect brake valve delivery line to top inlet port and
line from control valve to side inlet port.
TW-1
™
CONTROL VALVE
1. Place valve handle through mounting hole.
2. Install dial plate; tighten screws.
3. Connect air lines:
(a) from brake valve to inlet port.
(b) to limiting and quick release valve from delivery port.
DISASSEMBLY
LIMITING AND QUICK RELEASE VALVE
1. Remove four (4) cap screws and lockwashers; separate
cover, sealing ring and body.
2. Push piston from body.
3. Remove piston o-rings.
4. Remove exhaust valve, valve guide and spring.
5. Pull the valve stem through the piston; remove inlet valve
from stem.
TW-1
™
CONTROL VALVE
1. Remove inlet valve cap nut, spring and inlet/exhaust valve.
Remove cap nut seal ring.
2. Drive out lever pin and remove lever.
3. Remove plunger and plunger spring.
4. Remove plunger o-ring.
