BENDIX R-6 RELAY VALVE User Manual

1
®
Bendix
®
R-6
™
Relay Valve
SD-03-1060
SERVICE
PORT
RELAY PISTON
DELIVERY
PORTS (4)
R-6
™
RELAY
VALVE INSERT
RETURN
SPRING
FIGURE 1
FIGURE 2
DESCRIPTION
The relay valve in an air brake system functions as a relay
station to speed up the application and release of the brakes.
The valve is normally mounted at the rear of the vehicle in
proximity to the chamber it serves. The valve operates as a
remote controlled brake valve that delivers or releases air to
the chamber in response to the control air delivered to it
from the foot brake valve or other source. The R-6
™
relay
valve is a piston operated valve. For ease of servicing, an
“insert” or “cartridge” type inlet/exhaust valve is employed.
This feature permits service of the inlet/exhaust valve without
line removal. The R-6
™
relay valve may be mounted directly
to or remotely from the reservoir which provides its supply
pressure. Standard porting consists of one (1) service port
and four (4) delivery ports. There are two (2) supply ports in
the reservoir mounted valve and one (1) supply port in the
remote mount valve.
OPERATION
APPLYING
Air pressure delivered to the service port enters the small
cavity above the piston and moves the piston down. The
exhaust seat moves down with the piston and seats on the
inner or exhaust portion of the inlet/exhaust valve, sealing
off the exhaust passage. At the same time, the outer or inlet
portion of the inlet/exhaust valve moves off its seat, permitting
supply air to flow from the reservoir, past the open inlet valve
and into the chambers.
BALANCED
The air pressure being delivered by the open inlet valve also
is effective on the bottom area of the relay piston. When air
pressure beneath the piston equals the service air pressure
above, the piston lifts slightly and the inlet spring returns
the inlet valve to its seat. The exhaust remains closed as
the service line pressure balances the delivery pressure.
(NOTE: Some valves are equipped with a piston return spring
which will assist the lifting of the piston). As delivered air
pressure is changed the valve reacts instantly to the change
holding the brake application at that level.
EXHAUST
SUPPLY
PORT
SUPPLY PORT
(RESERVOIR
MOUNT TYPE)

BENDIX R-6 RELAY VALVE Specifications

General

Type	Relay Valve
Model	R-6
Manufacturer	Bendix
Category	Control Unit
Maximum Operating Pressure	150 psi
Material	Aluminum
Application	Commercial Vehicle Air Brake Systems
Operating temperature range	-40°F to +250°F
Mounting	Bracket mount

Summary

Bendix R-6 Relay Valve Overview

Description of Relay Valve

Explains the function of the relay valve in air brake systems and its piston-operated design.

Operation: Applying

Details how air pressure applies the brakes by moving the piston and opening the inlet valve.

Operation: Balanced

Describes how equal pressure above and below the piston balances the valve, holding the brake application.

Relay Valve Operation and Maintenance

Operation: Releasing

Explains how releasing service port pressure allows air to exhaust, releasing the brakes.

Preventive Maintenance Guidelines

Provides recommendations for regular inspection and maintenance intervals for the relay valve.

Operating and Leakage Test Procedures

Outlines tests to check brake application, release, and identify leakage points in the valve.

Removing the Relay Valve

Step-by-step instructions for safely removing the relay valve from the vehicle.

Relay Valve Servicing and Assembly

Installing the Relay Valve

Instructions for installing the relay valve, connecting air lines, and testing.

Disassembly of Relay Valve

Procedure for taking apart the relay valve, including cover and piston removal.

Inlet/Exhaust Valve Insert Disassembly

Specific steps for disassembling the removable inlet/exhaust valve insert.

Cleaning and Inspection

Guidance on cleaning parts and inspecting for wear or damage.

Assembly of Inlet/Exhaust Valve

Steps for reassembling the inlet/exhaust valve insert.

Complete Valve Assembly

Procedure for reassembling the entire relay valve after servicing.

General Safety Precautions

Critical Safety Instructions

Essential warnings and precautions for working on air brake systems to prevent injury or death.