17
1/2-5/8 I.D. VACUUM LINES
Cut a two inch length of hose from the provided 3/8” vacuum hose and slide one end
1.
onto the green end of the check valve. Insert the tee into the other end.
Cut another two inch length of hose and insert the open (black) end of the check
2.
valve. Slide the hose adapter into the other end.
Cut another two inch length of hose and insert the open end of the tee into it. Slide
3.
the other hose adapter into the other end.
Cut out a portion of the existing larger vacuum hose out and slip adaptors and hose
4.
clamps into the open ends of the hose. Make sure the black end of the check valve
is toward the motor.
Cut the hose coming from the Demco unit to the proper length and slide onto the
5.
tee. Make sure enough excess is left to avoid kinks.
Fig 13.2
Step 11: Testing the Install
Turn on the toggle switch.
1.
Push the brake pedal down in the towed vehicle. The notification light will illuminate. If
2.
not, check the brake-light switch connection and the ground connection.
Remove the breakaway pin and observe the operation of the cylinder. Note the cable
3.
attached to the firewall. It should be as close to an inch above being straight with the
cylinder as possible (see FIG 14.1 page 11). When it is in this location, the cable will be
straight with the cylinder when the brake pedal is in the down position. The vacuum pump
will run continuously, and apply the brakes of the towed vehicle. As the pump runs, more
brake effort is applied to the towed vehicle until the maximum effort is reached. Let the
pump run for about 10 seconds and replace the breakaway pin.
