Bendix Commercial Vehicle Systems TC-7 TRAILER CONTROL BRAKE VALVE - Manual (Page 3)

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5. Remove the TC-7 ™ valve handle(16) by first removing the
flat head Phillips machine screw(14) from the center of
the head/handle assembly.
6. Dismount the TC-7 ™ valve from the steering column.
DISASSEMBLY
The following assembly and disassembly instructions are
written for the use of a Bendix Maintenance Kit 102145.
If the valve is disassembled in a vise, be sure that the vise is
not overtightened as the body and internal parts will distort.
1. Remove and discard the adjusting ring lockwasher(3).
2. Remove and retain adjusting ring(6).
NOTE: A spanner wrench can be used to rotate the adjusting
ring, but if such a wrench is not available, the
adjusting ring can be returned with a small
screwdriver inserted in one of the inner notches of
the ring.
3. Remove and discard retaining ring(2).
4. Remove adjusting ring adapter(4), cam follower(5), sealing
ring(15) and friction washer(17). Discard sealing ring(15)
and o-rings (18 & 19). Retain all other parts.
NOTE: Note whether friction washer is installed with ribs
against or away from sealing ring. Must be installed
same-way during assembly.
5. Remove and retain cam(7) and graduating spring(8).
6. Remove and retain piston(9). Remove and discard
o-ring(10) from piston(9).
7. Remove and discard piston return spring(11).
8. Using an 11/16" deep well socket wrench, remove and
discard inlet and exhaust valve assembly(12) and
o-ring(13).
ASSEMBLY
Prior to assembly, wash parts retained during disassembly
in mineral spirits and dry thoroughly. Using Bendix lubricant
291126 or a silicone lubricant equivalent to Dow Corning
55-M, lubricate the body bores, cam, cam follower and all
o-rings and o-ring grooves. NOTE: Do not lubricate sealing
ring, friction washer or cam follower serrations.
1. Install o-ring(13) on inlet and exhaust valve assembly(12)
and using an 11/16" deep well socket wrench, install
inlet and exhaust valve assembly(12). Torque to 15 inch
pounds.
2. Install piston return spring(11).
3. Install o-ring(10) on piston(9) and install piston(9) in
body(1).
4. Install graduating spring(8) in body(1).
5. Install cam(7) in body(1) with flat side toward graduating
spring. Index cam “ears” to corresponding slots in body.
6. Install rubber sealing ring(15) on cam follower(5).
7. Install the friction washer(17) on cam follower(5) in same
manner as noted in Step 4 of Disassembly.
8. Install cam follower(5) in body.
NOTE: Stop “ear” on cam follower will not permit improper
assembly of cam follower; however, make certain
that the positioning “ear” of the friction washer fits
in the wide slot in the body.
9. Install o-ring(18) in adjusting ring adapter(4) and install
o-ring(19) in adjusting ring(6).
10. Install adjusting ring(6) in adapter(4) until adjusting ring
is flush with the underside of the adapter.
NOTE: There are two indexing lugs on the adapter that fit
into slots in the valve body when the adapter is
installed. Be sure to install the adjusting ring with
its wrench slots accessible (up) after the valve is
assembled.
11. Position the adapter(4) and adjusting ring(6) assembly
over the cam follower(5), making certain the adapter lugs
fit into the body slots.
12. Push down on cam follower(5) and install snap ring(2).
Be certain the snap ring is completely seated in its
groove.
NOTE: If lugs on adapter(4) are not in their body slots, the
snap ring cannot be installed completely.
13. Before installing the lockwasher(3), adjust the valve as
described.
ADJUSTMENT
Generally, the TC-7 ™ brake valve should deliver full reservoir
pressure; however, there are a few exceptions in special
applications.
1. If the delivered pressure is below specified final delivery
pressure, it can be adjusted by removing the head and
adjusting ring lockwasher and rotating the adjusting ring
clockwise to raise the delivery pressure.
Care should be taken not to raise the delivery pressure
beyond the design limits; exhaust opening could be
restricted.
2. If the delivery pressure is above specified final delivery
pressure, it can be lowered by rotating the adjusting
ring counter-clockwise.
NOTE: A spanner wrench can be used to rotate the adjusting
ring, but if such a wrench is not available, the
adjusting ring can be turned with a small screwdriver
inserted in one of the inner notches of the ring.
3. After adjustment is complete, install lockwasher(3) to
hold the adjustment.