BRACKET AS 2889729 - Caterpillar

Check Condition
Park the machine on level ground. Fully retract the boom and lower the boom.
Remove the cover from the rear of the boom.
A limited inspection of the chains can be made through the rear of the boom. If the chains are corroded, the chains must be removed from the boom for cleaning and a full inspection. If the chains require lubricant, the chain must be removed from the boom for cleaning and a full inspection. Refer to the Operation and Maintenance Manual, "Boom Chain-Inspect/Lubricate" for every 3000 service hours or a 2 year maintenance interval.Check Tension
Raise the boom to the maximum angle. This ensures that all sections of the boom are fully retracted. If the retraction chain requires adjustment and the boom is retracted in a lowered position, all the sections will not fully retract.
The boom can fall if a control is moved or if a hydraulic component fails. This can cause personal injury or death. Support the boom with stands. Do not rely on the cylinder to hold the boom up.
Illustration 1 g00569760
Lower the boom to the horizontal position and install a suitable stand under the first section in order to prevent the boom from falling unexpectedly.
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Measure the clearance between the spacer brackets on top of the boom. If the clearance is less than 20 mm (0.8 inch) the chains require adjustment. Note the position of spacers (1) .Chain Adjustment
Remove spacers (1) and the mounting hardware from the stowed position.
Raise the boom sufficiently above the stand and extend the boom approximately 600 mm (2 ft).
Retract the boom until the distance between the spacer brackets is just over 20 mm (0.8 inch). Lower the boom to a position just above the stand and stop the engine.
Illustration 3 g00569762
Install spacers (1) between the spacer brackets and tighten the hardware. The brackets must be in full contact with the spacers.
Illustration 4 g00569763
Back view of first section
Remove locking bolt (2). Turn the extension chain adjusting bolt (3) counterclockwise by three revolutions.
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The locknut (4) and retraction chain adjusting nut (5) are located on front part of the first section of the boom on the bottom.
Remove locknut (4) and tighten retraction chain adjusting nut (5) to a torque of 55 N m (40 lb ft). Install the locknut and tighten the locknut.
Illustration 6 g00569763
Back view of first section
Tighten extension chain adjusting bolt (3) to a torque wrench setting of 85 N m (63 lb ft). Tighten the bolt further until the bottom flat on the bolt head is horizontal. Install locking bolt (2) .
Illustration 7 g00569765
Remove spacers (1) between the spacer brackets and install the spacers in the stowed position.
Install the cover on the rear of the boom.
Remove the stand and lower the boom.