CONFIDENTIAL TIBU3632-00

The small spool in the valve of the boom lowering control valve and the stick lowering control valve may stick or seize in the bore of the plug. The result of the sticking spool may be poor controllability in the boom down function. Another symptom can be high vibrations on the stick during downward movement.

The 152-5441 Spool will be replaced by the new 222-3344 Spool in production. The new spool will be slightly longer in order to limit the spool?s displacement. The ends of the new spool will have a smaller diameter on each end in order to eliminate seizing in the bore. The new spool is a part of the new 222-3347 Valve Group.

Illustration 1. Compare Existing Spool (A), New Spool (B).

Check the boom lowering control valve (BLCV) and the stick lowering control valve (SLCV) if machine performance resembles the symptoms that are described in the problem. Use the following instructions for resolving the complaint.

1. Remove the 152-5440 Valve (1) from the BLCV or SLCV valve. See Illustration 2.



Illustration 2. Remove 152-5440 Valve (1) for replacement.
(2) plug assembly. (3) Existing spool.

 

2. Install one 3J-7354 O-ring Seal on one 9S-8002 Plug.
3. Install the plug assembly (4) from Step 2 into the new 222-3347 Valve . Tighten the plug assembly to a torque of 16 N× m (12 lb ft). See Illustration 3.

NOTE: Do not reuse the original plug assembly (2) from the
152-5440 Valve. The original plug assembly will cause a valve malfunction.

4. Install the new 222-3347 Valve (6) into the control valve. Tighten the valve to a torque of 215 ± 25 N× m (155 ± 18 lb ft).

Illustration 3. View of lowering control valve with a new 222-3347 Valve (6) and the new plug assembly (4).

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