1
SD-03-3656
Bendix
®
TP-3DC
™
Tractor Protection Valve with Double Check
FIGURE 1
- TP-3DC
™
TRACTOR PROTECTION VALVE WITH DOUBLE CHECK
AUXILIARY SUPPLY
1/4" -18 NPT
DATE CODE
STAMPED HERE
TRACTOR SUPPLY
1/4"-18 NPT
TRACTOR CONTROL
(PRIMARY) 3/8"-18 NPT
LABEL WITH
TP-3DC
™
VALVE
O.E. PC. NO. HERE
TRAILER CONTROL
1/2"-14 NPT
QR-L
™
VALVE FACTORY
INSTALLED ON SOME
TP-3DC
™
VALVE MODELS
1/2"-14 NPT
1/2"-14 NPT
TRACTOR
CONTROL
(SECONDARY)
3/8"-18 NPT
STOP LIGHT
SWITCH
1/4"-18 NPT
TRAILER CONTROL
1/2"-14 NPT
DESCRIPTION
The tractor protection valve system protects tractor air
brakes during trailer breakaway and/or when severe air
leakage develops in the tractor or trailer. This function is
required by law.
In normal use the tractor protection valve is used to shut off
the trailer control line before disconnecting the tractor from
the trailer. It is usually mounted at the rear of the tractor
cab, and it is used in conjunction with a dash-mounted
control valve.
The TP-3DC
™
valve integrates tractor protection and double
check valve functions. It also has an integral single check
valve that prevents trapping of air in the trailer control line.
This prevents service and spring brake compounding, and
it avoids a trailer roll away situation if the trailer is parked
with the air applied.
A stoplight switch port allows direct stoplight installation,
and the auxiliary supply port, when connected to the
BP-R1
™
control port, eliminates a tee in the tractor
supply line. Also, a QR-L
™
valve can be factory installed
in the trailer control and/or supply port to meet timing
requirements.
Port
Embossed I.D. Thread Size
Tractor Supply
TRAC SUP
1/4"-18 NPT
Auxiliary Supply
AUX SUP
1/4"-18 NPT
Tractor Control (Primary)
TRACT CONT
3/8"-18 NPT
Tractor Control (Secondary) TRAC CONT
3/8"-18 NPT
Stop Light Switch
STP LT SW
1/4"-18 NPT
Trailer Supply
TRLR SUP
1/2"-14 NPT
Trailer Control
TRLR CNTL
1/2"-14 NPT
Weight: 1.5 lbs.
Material: Die-cast aluminum
Operating pressure: 150 psi maximum
Operating temperature: -40° to 200° F
Figure 1 shows the TP-3DC
™
valve with its port designations,
O.E. piece number, and date code identifi cations.
Figure 2 is a sectional view of the TP-3DC
™
valve, and
Figure 3 presents the TP-3DC
™
valve in a partial air brake
system schematic.
