FRAME AS 4853534 - Caterpillar

Manual Barring Group (50:1)
Illustration 3 g01194661
Manual Barring Group (50:1 reduction)
(1) Shaft
(2) Locking nut
(3) Adapter
(4) Knob An electric wrench or an air wrench may be used with the manual barring group in order to turn the engine slowly. The manual barring group is used while service work is being performed.Use the following procedure in order to engage the manual barring group:
Loosen locking nut (2).
Pull knob (4) outward while pressing inward on locking nut (2) until the nut is flush with the housing. The nut is part of the pinion shaft which is spring loaded.
Release knob (4) and slowly remove hand pressure from locking nut (2) until the knob engages in the slot of the pinion shaft. Note: If locking nut (2) cannot be flush with the housing, the shaft gear is not meshed with the flywheel ring gear. Maintain inward pressure on the nut while adapter (3) is carefully adjusted. Adjustment of the adapter is achieved by turning the adapter. The adjustment may require the adapter to be turned more than one revolution in either direction. Adjust the adapter until locking nut (2) can be flush with the housing.When the manual barring group is in the engaged position, the engine starting system is disabled.To turn the engine crankshaft, use adapter (3). In order to operate the manual barring group, use an electric tool or an air tool. The tool must be capable of producing the required torque. The engine will turn one revolution in less than three minutes if the speed of the tool is 700 rpm. Any power tool that is used to operate the manual barring group should be equipped with a cushion clutch in order to prevent damage to the gears.
Do not use an impact wrench to operate the barring device. The use of an impact wrench will cause gear tooth failure.
The engine crankshaft is locked in place when the pinion gear on shaft (1) is engaged with the flywheel ring gear.Use the following procedure in order to disengage the manual barring group:
Pull knob (4) outward while pressing inward on locking nut (2) until the spring on shaft (1) moves the pinion to the disengaged position.
Check that the pinion gear is fully disengaged. Note: The pinion gear is fully disengaged when locking nut (2) passes by the housing.
Release knob (4).
Tighten locking nut (2) according to the torque that is listed in the engine's Specifications manual. Note: If shaft (1) fails to fully return to the disengaged position, rotate the adapter in either direction. Rotating the adapter in either direction reduces the side loading (friction) between the pinion gear and the flywheel ring gear.
Do not operate the engine starting motor until the barring group pinion gear is fully disengaged from the flywheel ring gear. Serious damage to the engine could result.
When the manual barring group is not activated, the manual barring group must be disengaged from the flywheel and the manual barring group must be secured in the disengaged position.Electrical Barring Group
Illustration 4 g01194669
Electrical barring group
(1) Barring motor
(2) Knob
(3)