4
FIGURE 5
TP-4
™
TRACTOR PROTECTION VALVE (SERVICE APPLICATION)
10. Disconnect line from secondary circuit delivery (SCD)
port and plug end of line. Make a foot brake valve
application and check secondary circuit delivery (SCD)
port of valve for leakage. Leakage at port indicates
double check valve requires servicing. Remove plug
from line and reconnect to valve.
11. Make a foot valve application and test for gasket
leakage. Tighten bolts if necessary. (See #4 “Assembly”
for Proper Torque Sequence.)
If the TP-4
™
tractor protection valve does not function as
described above or leakage is excessive, it is recommended
that it be replaced with a new or remanufactured unit, or
repaired with genuine Bendix parts available at authorized
Bendix parts outlets, in which case the following should
prove helpful.
DISASSEMBLY
1. Remove six (6) cap screws (11) Figure 2 and
lockwashers. This will permit separation of the body,
intermediate body and lower body and gaskets. (9) &
(10)
2. Remove piston (12) and piston spring (8) from
intermediate body. Remove o-rings (2) and (3) from
piston (12).
3. Remove both double check valve shuttles (4) and
guides from body.
4. Remove large retaining ring (13) from lower body.
Remove valve retainer (14), spring (7) and inlet valve
(6). Remove o-ring (5) from valve retainer.
(NOTE: Older revision valves may have an o-ring (1),
sealing disc (16) and small retaining ring (15) as
shown in Figure 3. These need not be disturbed
unless leakage was noted, in which case the
retaining ring must be removed and the o-ring
replaced.)
CLEANING AND INSPECTION
1. Clean all metal parts in mineral spirits and dry them
completely.
2. Inspect all parts for excessive wear or deterioration.
Inspect valve seats for nicks or burrs. Check the valve
spring for cracks or corrosion.
3. Inspect the bores of the valve housing for deep scuffi ng
or gouges.
Replace all parts that were discarded and any parts not
found to be serviceable during inspection, using only
genuine Bendix replacement parts.
ASSEMBLY
Before assembling the TP-4
™
valve, lubricate all o-rings,
o-ring grooves, body bores and rubbing surfaces with
Bendix silicone lubricant (Pc. No. 291126) or equivalent.
STOP LIGHT SWITCH
STOP LIGHT SWITCH
TO TRAILER SERVICE
TRAILER
EMERGENCY
VENT
TRAILER SUPPLY VALVE
TO TRAILER
EMERGENCY
TRAILER CONTROL VALVE
TWO WAY VALVE
PRIMARY
RESERVOIR
SECONDARY
RESERVOIR
DUAL
BRAKE
VALVE
TO LIMITING AND
Q.R. VALVE
A
B
C
