Blue Ox BRK4000 - Manual (Page 2)

BRK4000
Push Cylinder BrakeSafe™
Installation Instructions
405-0312 Rev A Page 2 of 6 9/27/13
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 five 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 fitting. Cut the tubing and push the tubing into
each side of the tee fitting, making sure the tubing is bottomed into the fitting. 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 fitting. 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 fitting that is not supplied,
most hardware stores have brass pipe fittings. (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)
BrakeSafe TM is a proportional braking system that can be used on coaches with Total Air or Air Over Hydraulic
braking systems. With a BrakeSafe TM you will use your coach’s air brakes by tapping into the brake relay air
source.
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
Figure 1
Figure 2