5034362 JOHNSON RELAY, TNT

Personal injury can result from hydraulic oil pressure and hot oil.Hydraulic oil pressure can remain in the hydraulic system after the engine has been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic system.Make sure all of the work tools have been lowered to the ground, and the oil is cool before removing any components or lines. Remove the oil filler cap only when the engine is stopped, and the filler cap is cool enough to touch with your bare hand.
Escaping fluid under pressure, even a pinhole size leak, can penetrate body tissue, causing serious injury, and possible death. If fluid is injected into your skin, it must be treated immediately by a doctor familiar with this type of injury.Always use a board or cardboard when checking for a leak.
Engage the parking brake.
Install the steering lock.
Illustration 1 g02009358
Position the bucket or the work tool just above the ground at a slight downward angle. the angle ensures that the head end of the lift cylinders is pressurized.
Turn the engine start switch to the OFF position.
When the engine has stopped, turn the engine start switch back to the ON position. The spools can be shifted to allow for oil flow.
Move the implement lockout switch to the UNLOCKED position.
Move the lift control lever to the FLOAT position and the tilt control lever to the TILT BACK position at the same time. This action allows the bucket or the work tool to tilt back while the boom is lowered. The bottom of the bucket or the work tool should rest flat on the ground. The weight of the linkage should be supported by the ground. The pressure from the head end of the lift cylinders and from the ride control accumulator is now vented to the hydraulic tank.
When the bucket or the work tool has settled to the ground, move both control levers to the HOLD position. Then, cycle the control levers, including the auxiliary function levers if equipped, through all positions. Cycling the levers will purge any remaining pressure from the implement hydraulic system.
Turn the engine start switch to the OFF position. Note: If work on the non-engine end frame is required, then the linkage will need to be supported by a suitable stand. Use the above procedure to purge the pressure out of the system after the linkage is resting on a suitable stand. Never work on the hydraulics without first securing the linkage.
Slowly loosen the hydraulic tank filler cap in order to release the pressure from the hydraulic tank.
After all of the pressure has been released, tighten the hydraulic tank filler cap. The hydraulic system pressure has now been released. Hydraulic lines and components can now be removed. Release Procedure (Steering System)
Ensure that the engine is off and the main disconnect key and cab key are in the On position. Do not start the engine.
Cycle the steering controls between left and right for a few cycles. With the engine off, the steering linkage will come to a resting position and will not steer.
The steering system is now at low pressure. Release Procedure (Ride Control Accumulators)
Ensure that the linkage has been fully lowered to the ground and the implement pressure has been released.
Ensure that the engine is off and the main disconnect key and cab key are in the On position. Do not start the engine.
Turn ride control on by pressing the Auto button on the control panel. The display will show the following message, "Auto Ride Control On."
Move the lift control lever to the float position. The lever should stay in the float position for at least 15 seconds because of the detent. The head end of the lift cylinder is connected to the ride control accumulators. A balancing spool will balance the pressure between the ride control accumulators and the pressure in the lift cylinders. Since the linkage is resting on the ground, the pressure in the cylinders should be zero. Therefore the ride control accumulators will drain to zero during the 15 second period that float is enabled.
After the 15 second period, return the joystick to the neutral position. The ride control accumulators should now be at low pressure. Release Procedure (Fan System and Braking System)
Depress the brake pedal repeatedly in order to release any pressure in the fan system and the braking system. The number of brake applications required to release the pressure may vary due to the level of charge at shutdown. The number of brake applications needed to drain the accumulators could exceed 60.
Slowly loosen the hydraulic tank filler cap in order to release the pressure from the hydraulic tank.
After all of the pressure has been released, tighten the hydraulic tank filler cap. The hydraulic system pressure has now been released. Hydraulic lines and components can now be removed. Dead Electronics
If the electronics fail, to relieving all stored hydraulic oil pressure may not be possible. The following precautions should be taken.
Turn the engine OFF.
The machine should be secured with a lockout.
Stand clear of the linkage when preparing to lower the lift arms. The linkage will drop in less than 15 seconds.
Barriers should be used in order to prevent personnel from entering areas that implement drift or movement could be hazardous.
Illustration 2 g03319065
To lower the lift arms open valve (1) .
Do not open or disassemble any hydraulic circuits until the electronic controls are fixed and can be used to relieve stored hydraulic pressure.