Usage:
12G, 14G, 16G, 120G, 130G And 140G Motor Graders
- SUPPLEMENT: 06/22/81
SERVICE MAGAZINE, NOVEMBER 10, 1980, PAGE 2. In the article, "Valve Assembly And Nipple Moved From Centershift Lock Control Group To Brake Control Group To Prevent Unauthorized Operation," change the first sentence of the NOTE to read:
The disconnect switch must be in the "OFF" position and the centershift lock pin valve in the "INDEX" position for the valve assembly to serve its purpose.
The original NOTE did not give a specific position for the lock pin valve. If the lock pin valve is in any position other than "INDEX," there can still be just enough air in the system to release the parking brake, if only one time.
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Description of Change: A solenoid air valve assembly and nipple have been moved from the center-shift lock control group to the brake control group for the above model motor graders.
The valve assembly and nipple are used as a safety feature to prevent unauthorized operation of the machine and/or accidental rotation and lowering of the blade when the machine is shut off and unattended.
The valve assembly is now located in the air supply line for the parking brake valve and the centershift lock pin valve.
When the machine is parked and the disconnect switch is turned off, the current flow to the valve assembly, as well as to all other components in the electrical system, is stopped. The valve assembly then closes to shut off the air supply to the parking brake circuit and the centershift lock circuit.
Since air under pressure is required to release the parking brake and to lock or retract the centershift lock pin, the parking brake can not be released and the blade can not be rotated or lowered.
NOTE: The disconnect switch must be off for the valve assembly to serve its purpose. As an additional precaution, the operator should lower the blade when the motor grader is parked, and remove the key after the disconnect switch is turned off.
Formerly, the valve assembly and nipple were used in the centershift lock control group to prevent accidental rotation and/or lowering of the blade when the machine was parked and unattended. See the October 20, 1980 Service Magazine article, "Valve Assembly Used In Centershift Lock Control Group To Prevent Accidental Rotation And/Or Lowering Of The Blade," on Page 4.
Adaptable To: The 2G5694 Valve Assembly and 5K2408 Nipple can be moved from the centershift lock circuit to the parking brake circuit on all 12G, 14G, 16G, 120G, 130G and 140G Motor Graders, so equipped. The 4H6147 Connector also is removed from the centershift lock control group and not used.
Illustration 1 shows the location of the 2G5694 Valve Assembly and the 5K2408 Nipple in the brake control groups.
Illustration 2 shows the new and former locations of the valve assembly in the air system schematic.
Illustration 1.
Illustration 2.