6.Pressure Bleed - There are two options for pressure bleeding the brake system, either using a commercial pressurized bladder type bleeder or by activating the 691 Power Unit.
Using commercial bleeder Follow manufacturer's instructions.
Using 691 Power Unit
A. Activate the 691 System.
Be careful when opening the bleeder screw, it will be under high pressure. Wear safety glasses.
B.Starting at the actuators and moving outward to foundation brakes, open bleeder screw 1/2 turn. The 691 Power Unit will run with the re- lease of pressure and will stop automatically when the actuator reaches the end of its stroke. Most air will come out at end of the actuator stroke.
C.After power unit stops running, close the bleeder screw.
D.Deactivate the 691 System. After 691 Power Unit stops running, slowly depress and release brake pedal 3 to 5 times or until a firm pedal is achieved. This step is to replenish the actua- tors. NOTE: The 691 Power Unit will run during first brake application.
E.Be sure the 691 Power Unit reservoir and vehicle master cylinder reservoir remain filled with proper fluid.
F.Repeat steps A thru E at each bleed point until all air is purged before switching to the next bleed point.
G.After the above steps are completed, check to see if brake pedal height and "feel" are the same as before the 691 System was installed. If the pedal does not "feel" as firm as before, let the vehicle sit for several hours or overnight and repeat pressure bleeding.
7.Activate the 691 System. Open bleeder screw 1/4 turn. See Figure 23. Close bleeder screw when a steady stream of fluid is present.
Power Unit | Power Unit | |
Bleed Point | ||
Bleed Point | ||
|
FIGURE 23
Before moving the vehicle, a firm pedal must be achieved when the 691 System is deactivated. If a firm pedal is not achieved, repeat bleeding procedure for the 691 System and the service brake system until a firm pedal is achieved. Make several brake applications with vehicle stationary and check fittings for leaks.
8. Reconnect horn or other warning devices.
HORN WARNING CIRCUIT TEST
The 691 Control Module provides two alarm wires: "direct alarm" and "delayed alarm". The "direct alarm" wire is the white wire in the User Interface cable. It provides a ground signal whenever the system is pressurizing. It activates the User Interface audible alarm. The "delayed alarm" wire, the yellow wire in the main 691 wire harness, is also referred to as the horn wire. It provides a ground signal if the system takes longer than nine seconds to initially pres- surize, or anytime the system is
The yellow wire must be connected to the vehicle's horn or to a form of warning device that will guarantee that the operator is aware that the system is
The horn warning circuit must be tested on a regular basis.
After the system has been activated and is locked, momentarily unplug the
If the horn does not activate during this test, determine the cause of the problem and correct before using the 691 Brake Lock System.
691 OPERATING INSTRUCTIONS
Do not operate power unit without first filling with proper fluid.
Using 691 as a Lock System
(Only units with 691 User Interface)
To Activate Lock System
1.Bring vehicle to a complete stop.
2.Set mechanical parking brake.
3.Move the user interface lock/release switch to the "lock" position.
4.User Interface alarm will sound and then deactivate after reaching locking pressure.
5.The "locked" indicator lamp will come on after locking pressure is reached.
6.Apply other provided holding devices.
NOTE
If pressure drops below required system pressure, the "locked" indicator lamp will go off and user interface alarm will activate. This process may take only a fraction of a second.
If user interface alarm does not sound or fails to deactivate or if the "locked" indicator lamp does not remain on, discontinue use of the 691 Brake Lock System. Determine the cause of the problem and correct before using.
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