Manual

ManualsBrandsBendix Commercial Vehicle Systems ManualsEquipmentSR-5 TRAILER SPRING BRK VALVE 4/11

SD-03-4516

Bendix

SR-5

™

Trailer Spring Brake Valve

FIGURE 1 - BENDIX

SR-5

™

TRAILER SPRING BRAKE VALVE (*SHOWN WITH OPTIONAL ANTI-COMPOUNDING COVER)

SR-5

™

VALVE

IDENTIFICATION

HOLE

1/4” NPT TRAILER

SERVICE

1/4” NPT TRAILER

SUPPLY

EXHAUST

COVER*

1/4” NPT

SERVICE

RESERVOIR

(2)

3/8” NPT

DELIVERY (4)

1/2” OR 3/4” NPT

SPRING BRAKE

RESERVOIR

PRESSURE

PROTECTION

VALVE

DESCRIPTION

The Bendix

SR-5

™

valve is a reservoir-mounted trailer

valve that can control up to four spring brake actuators

during parking or emergency applications. It has the

following capabilities:

• Automatically applies trailer spring brakes in the event

of a breakaway or trailer supply line failure.

• Protects trailer reservoir(s) air pressure in the event of

a breakaway or trailer supply line failure.

• Allows no automatic trailer spring brake application

with air pressure loss in trailer reservoir(s).

• Allows the trailer spring brakes to be applied and released

repeatedly with a failed trailer reservoir(s):

• Optional anti-compounding-prevents an overriding

service brake signal while the trailer supply line is at

atmospheric pressure.

• Does not allow service system charging if a failure occurs

in the parking brake circuit.

PORTS

1 - 1/2" or 3/4" NPT Spring Brake Reservoir Mounting

(SPR BK RES)

1 - 1/4"-18 NPT Trailer Supply (TRL SUP)

1 - 1/4"-18 NPT Trailer Service (TRL SER)

4 - 3/8"-18 NPT Delivery (DEL)

2 - 1/4"-18 Service Reservoir (SERV RES)

1 - Exhaust (EXH)

The SR-5

™

valve appears very similar to the Bendix

SR-2

™

valve. Both valves consist of a die-cast aluminum body and

cover, pressure protection valve, and reservoir-mounting

nipple. However, Figure 1 notes the distinguishing

characteristic of the SR-5

™

valve–a hole drilled into the

ﬂ at surface between the pressure protection valve and

the body.

Summary of content (9 pages)

PAGE 1
SD-03-4516 Bendix® SR-5™ Trailer Spring Brake Valve PRESSURE PROTECTION VALVE 1/4” NPT SERVICE RESERVOIR (2) SR-5™ VALVE IDENTIFICATION HOLE COVER* 1/4” NPT TRAILER SUPPLY 3/8” NPT DELIVERY (4) 1/4” NPT TRAILER SERVICE EXHAUST 1/2” OR 3/4” NPT SPRING BRAKE RESERVOIR FIGURE 1 - BENDIX® SR-5™ TRAILER SPRING BRAKE VALVE (*SHOWN WITH OPTIONAL ANTI-COMPOUNDING COVER) DESCRIPTION PORTS The Bendix® SR-5™ valve is a reservoir-mounted trailer valve that can control up to four spring brake actuators during p
PAGE 2
TRAILER SERVICE SERVICE/ SPRING BRAKE RESERVOIR SERVICE/SPRING BRAKE RESERVOIR SERVICE RELAY VALVE SR-5™ VALVE TRAILER SUPPLY TWO-TANK SYSTEM TRAILER SERVICE SR-5™ VALVE SERVICE/SPRING BRAKE RESERVOIR SERVICE RELAY VALVE TRAILER SUPPLY ONE-TANK SYSTEM FIGURE 2 - TYPICAL SYSTEM SCHEMATICS WITH BENDIX® SR-5™ TRAILER SPRING BRAKE VALVE 2
PAGE 3
TRAILER SERVICE CHECK VALVE D TRAILER SERVICE RES. CHECK VALVE B SERVICE RELAY VALVE PASSAGE A SERVICE/ SPRING BRAKE RESERVOIR CONNECTION TRAILER SUPPLY CONTROL PISTON EXHAUST DELIVERY SPRING BRAKE CHAMBER FIGURE 3 - CHARGING BELOW 70 PSI OPERATION CHARGING BELOW 70 PSI (SEE FIGURE 3) Air flows through the trailer supply line, enters the Bendix® SR-5™ valve trailer supply port, and moves the control piston.
PAGE 4
TRAILER SERVICE TRAILER SERVICE RES. SERVICE RELAY VALVE PRESSURE PROTECTION VALVE C CHECK VALVE D CHECK VALVE B SERVICE/ SPRING BRAKE RESERVOIR CONNECTION PASSAGE A TRAILER SUPPLY CONTROL PISTON EXHAUST SPRING BRAKE CHAMBER FIGURE 5 - PARK APPLICATION PARK APPLICATION (SEE FIGURE 5) PARK RELEASE WITH TRAILER CHARGED To park the trailer, either the trailer air supply valve or the system park control valve (in the tractor) is actuated. This vents the trailer supply line.
PAGE 5
TRAILER SERVICE CHECK VALVE F SERVICE RELAY VALVE ANTI-COMPOUNDING LINE SERVICE/ SPRING BRAKE RESERVOIR CONNECTION CHECK VALVE E TRAILER SUPPLY DELIVERY EXHAUST SPRING BRAKE CHAMBER FIGURE 7 - OPTIONAL ANTI-COMPOUNDING Note that pressure protection valve C will open if trailer supply air is greater than 70 psi. But check valves B and D will not open unless release pressure from the tractor exceeds trailer reservoir pressure.
PAGE 6
TRAILER SERVICE TRAILER SERVICE RESERVOIR PRESSURE PROTECTION VALVE C CHECK VALVE B SERVICE RELAY VALVE SERVICE/ SPRING BRAKE RESERVOIR CONNECTION TRAILER SUPPLY EXHAUST SPRING BRAKE CHAMBER FIGURE 8 - FAILED TRAILER RESERVOIR FAILED TRAILER RESERVOIR (SEE FIGURE 8) SERVICE CHECKS Should trailer reservoir pressure be lost, trailer service braking is no longer available. Pressure protection valve C will close at approximately 70 psi (minimum), retaining air pressure in the trailer supply line. 1.
PAGE 7
3. Place the trailer air supply valve in the exhaust position. The spring brakes should apply. Disconnect the trailer supply line and apply a soap solution to check for leaks. A 1" bubble in 5 seconds is permissible. REMOVAL 4. Reconnect the trailer supply hose coupling and recharge the trailer system. The spring brakes should release. Shut off the engine. Open the trailer reservoir drain cock. The tractor air system should bleed down to approximately 70 psi.
PAGE 8
FIGURE 9 - EXPLODED VIEW 8 13 22 14 21 PIPE PLUG 20 3 1 19 17 18 15 2 16 23 24 25 VALVE BODY 10 5 4 8 12 17 PIPE PLUG 18 9 11 7 6
PAGE 9
1. Remove the four screws (1) that secure the spring retainer (2) to the valve body. Note that the retainer is spring-loaded. Remove the screws while holding the retainer against its spring load. Then slowly remove the retainer. 2. Remove spring (3) and piston assembly (4). 3. Remove piston o-ring (5). Do not remove the retaining ring and stem from the piston. The piston is serviced as an assembly. 4. Note and mark the position of control piston cover (7).