Blue Ox BRK4000 User Manual

BRK4000

Push Cylinder BrakeSafe™

Installation Instructions

Serial Number

BRK4000

Push Cylinder BrakeSafe™

405-0312 Rev A Page 1 of 6 9/27/13

BRK4000

TO LEFT BRAKE ACTUATOR

TO RIGHT BRAKE ACTUATOR

MAIN AIR IN

PROPORTIONAL
AIR TO TOWED
BRAKE SYSTEM

OPTION 1

BRAKE RELAY

PROPORTIONAL PILOT

TOP PORT

AIR SOURCE LOCATION,
CUT TUBE, INSTALL TEE
FITTING

OPTION 2

PILOT AIR FROM
BRAKE PEDAL

OPTIONAL SERVICE AIR SOURCES

1. UNUSED RELAY PORT

2. TEE INTO BRAKE HOSE PORT

AIR SOURCE LOCATION,
CUT TUBE, INSTALL TEE
FITTING

MAIN PORT

RUN TUBING TO
REAR OF COACH

AIR ACTUATOR

BOTTOM DRAIN PLUG

HYD. MASTERCYLINDER

FRONT

ONLY TAP INTO SERVICE BRAKE AIR. AIR SHOULD FLOW
FROM TUBE OR PORT WHEN BRAKE PEDAL IS APPLIED.

NOTE:

AIR OVER HYDRAULIC
ASSEMBLY IS LOCATED
AHEAD OF FRONT AXLE,
ON DRIVER’S SIDE

Push Cylinder BrakeSafe™

Installation Instructions

BrakeSafeTM is a proportional braking system that can be used on coaches with Total Air or Air Over Hydraulic
braking systems. With a BrakeSafeTM you will use your coach’s air brakes by tapping into the brake relay air

source.

Locating Air Source On Coach

1. For coaches with total air brake systems, the brake relay is located ahead of the rear axle. This relay

has four to ve ports, some of which will be used. There is a right and left brake actuator hose coming
from this relay, these hoses go to the brake actuators of each rear tire of coach. There is a 3/8” O.D. pilot
tubing coming from one of the four ports coming from the brake relay. This is the SERVICE port that is the
preferred place to connect into proportional air that receives pilot air from the coach’s brake pedal. If this
port has a 3/8” hose coming from it, use the furnished tee tting. Cut the tubing and push the tubing into
each side of the tee tting, making sure the tubing is bottomed into the tting. On the bottom of some relay
valves there are four ports, three are used, the other has a 1/2” pipe plug. Remove this plug and install a
1/2”pipe to 3/8” tube tting. There should be no pressure coming from the port, unless the brake pedal is
pushed down. If there is, you need to look for another port. If your coach needs a tting that is not supplied,
most hardware stores have brass pipe ttings. (Figure 1)

2. For coaches with air over hydraulic braking systems, the air over hydraulic assembly is located in front
of front axle on the driver’s side. There is a drain plug on the bottom side of the air actuator, take this plug
out and install a 3/8” tube connector. (Figure 2)

Figure 1

Figure 2

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