TM-9-2330-335-14-P
SEMITRAILER, TACTICAL, BREAKBULK/CONTAINER TRANSPORTER, 22-1/2 TON, RESET M871R, M871A1R AND M871A2R
TECHNICAL MANUAL; FIELD AND SUSTAINMENT MAINTENANCE MANUAL (INCLUDES REPAIR PARTS AND SPECIAL TOOLS LIST)
SEPTEMBER 2008
TM-9-2330-335-14-P - Page 562 of 640
0096-20
TM 9-2330-335-14&P
0096
DISARMING INSTRUCTIONS
00096
1.
Place the single/piggyback or combination/tandem spring brake chamber in the fabricated/inspected disarming
chamber. Air brake chamber should be uncaged with caging bolt removed.
2.
Position the air brake chamber so the spring brake head can be easily accessed through the slots in the disarming chamber.
If the air brake chamber does not fit in the disarming chamber, it may be necessary to cut off the service push-rod. Close
the hinged access door of the disarming chamber, and lock hasps with bolts and nuts.
3.
Through one of the slot openings in the disarming chamber use an acetylene gas torch to cut a hole (1-1/2 to 2 in. [3.8 to
5.1 cm]) in the air brake chamber head to expose the power spring coil. DO NOT cut the power spring coil. See Figure 22
for approximate location to cut hole on housing side.
4.
Repeat step 3 for opposite side of the spring brake head. Cutting two holes opposite each other provides the torch with
sufficient oxygen for cutting the power spring coil.
5.
Cutting the first power spring coil may produce a low-pitched “pop” or may cause the spring brake chamber to
jump in the disarming chamber. Repeat this cutting process through the slot opening on the opposite side of the
disarming chamber.
WARNING
•
DO NOT cut the spring brake chamber clamp bolts before cutting the power spring coils. The
spring coils MUST be cut FIRST. If this WARNING is NOT heeded, the spring will prematurely
release 2,000 lb of pressure, and become an unexpected projectile that could cause injury or death
to personnel and damage to the equipment.
•
Do not place your hands or fingers inside the disarming chamber.
6.
To make sure you have completely cut the power spring coils, use a screwdriver or similar tool to ensure coils are loose
inside the head of the spring brake chamber. If the coils can be moved, the spring brake chamber has been rendered safe
and can be properly discarded.
END OF TASK
SUPPLEMENTARY INFORMATION
00096
1.
Many manufacturers do not rebuild or condone the use of rebuilt air brake chambers. This is because they are
very important safety devices that actuate foundation brakes and perform vital parking and emergency brake
functions. Because they operate in the worst possible environments under the most severe conditions, it is
impossible to accurately determine the condition and service life remaining in critical components such as the
non-pressure housing (mounting base), flange case (center section), power spring, and center push-rod seal.
These are all components that are typically “cleaned up” and/or repainted and reused in rebuilt actuators. With a
rebuilt actuator, you have no reliable way of knowing which components have been replaced and how long the
unit can be expected to last.
2.
If you do not have the capability to fabricate this disarming chamber and inspect it for safety, there is a commercially built
disarming chamber available from Jack Garner & Sons Welding which is AWS Code welded, has positive locking, and is
portable. This disarming box runs approximately $330. They may be reached at 717-367-2638 or 717-653-6551, FAX:
717-367-7906, E-Mail:
jack.garner@garnerwelding.com
. Their product may be viewed at:
END OF WORK PACKAGE
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