Bendix-commercial-vehicle-systems LQ-4 FRONT AXLE RATIO VALVE User Manual download pdf

SD-03-951

FUNCTION AND DESCRIPTION

The LQ-3

™

and LQ-4

™

front axle ratio valve is used on the

front or steering axle of a vehicle to limit the brake applica-

tion pressure to the actuators during normal service braking.

Limiting application pressure reduces the braking effort at

the foundation brakes on the steering axle. The supply and

delivery ports in both the LQ-3

™

and LQ-4

™

valves are iden-

tified with embossed lettering. The ports in the LQ-3

™

valve

are 1/4 inch N.P.T. and in the LQ-4

™

valve, 3/8 inch N.P.T.

The exhaust port is not threaded in either valve. Two mount-

ing holes are provided for 5/16 inch mounting bolts. Note:

When mounted on the vehicle the exhaust port should be

pointed down.

GENERAL OPERATION

The supply port of the LQ-3

™

or LQ-4

™

valve is connected to

the delivery port of the service brake valve. The delivery port

of the LQ-3

™

valve is connected to the service port of the

front axle relay valve or the adaptive braking modulator. The

LQ-4

™

valve may be used to operate brake chambers up to

Type 24 without relay or QRV.

Pressure delivered to the LQ supply port is reduced by 50%

as it passes through the valve and out the delivery port. The

50% reduction occurs only when brake application pressure

to the supply port of the LQ is between 0 psi and 40 psi.

Brake applications between 40 psi and 60 psi to the LQ

supply port are reduced by less than 50% and applications

above 60 psi are not reduced at all. An example would be:

65 psi delivered to the supply port results in 65 psi out the

LQ delivery port.

Bendix

LQ-3

™

& LQ-4

™

* Front Axle Ratio Valve

1/4" NPT

PISTON SPRING

HOLD OFF

SPRING

(WHEN REQUIRED)

LOWER PISTON

ASSEMBLY

INLET EXHAUST

VALVE SPRING

1/4" NPT

3/8" NPT

LQ-4

™

FRONT AXLE RATIO VALVE*LQ-3

™

FRONT AXLE RATIO VALVE

FIGURE 1 - LQ-3

™

AND LQ-4

™

FRONT AXLE RATIO VALVE

(*THE LQ-4

™

VALVE'S OPERATION IS IDENTICAL TO THE LQ-3

™

VALVE.

INTERNAL CONFIGURATION IS SLIGHTLY DIFFERENT.)

LQ-3

™

FRONT AXLE RATIO VALVE

EXTERIOR

1 2 3 4 5 6 7 8

Summary of Contents

Page 1 - * Front Axle Ratio Valve

1®SD-03-951FUNCTION AND DESCRIPTIONThe LQ-3™ and LQ-4™ front axle ratio valve is used on thefront or steering axle of a vehicle to limit the brake app

Page 2 - PSI OR LESS

2BRAKECHAMBERRESERVOIRTYPICAL LQ-3™ FRONT AXLE RATIO VALVE INSTALLATIONBRAKECHAMBERBRAKECHAMBERRESERVOIRLQ-3™VALVEBRAKECHAMBERTEELQ-4™VALVETYPICAL LQ-

Page 3 - 40 PSI OR GREATER

3FIGURE 6 - LQ-3™ FRONT AXLE RATIO VALVE* BRAKEVALVE APPLICATION AT 60 PSI OR GREATER.(*LQ-4™ VALVE OPERATION SAME AS LQ-3™ VALVE.)FIGURE 4 - LQ-3™ FR

Page 4 - DISASSEMBLY

4PREVENTIVE MAINTENANCEImportant: Review the Bendix Warranty Policy before per-forming any intrusive maintenance procedures. A warrantymay be voided i

Page 5 - THESE INSTRUCTIONS TO AVOID

57. Place the cover over the body in the proper position, asmarked in Step 1 of the Disassembly procedure.8. Using the four Phillips head screws and l

Page 6

69. Components with stripped threads or damagedparts should be replaced rather than repaired. Donot attempt repairs requiring machining or weldingunl

Page 7

Page 8

Comments to this Manuals

No comments

Bendix-commercial-vehicle-systems LQ-4 FRONT AXLE RATIO VALVE User Manual

Browse online or download User Manual for Equipment Bendix-commercial-vehicle-systems LQ-4 FRONT AXLE RATIO VALVE. Bendix Commercial Vehicle Systems LQ-4 FRONT AXLE RATIO VALVE User Manual

Summary of Contents

Comments to this Manuals

Related products and manuals for Equipment Bendix-commercial-vehicle-systems LQ-4 FRONT AXLE RATIO VALVE