Lull 6K Service Manual - Manual (Page 509)

Frame Tilt and Oscillation
Service Manual — Models 644B, 6K, 844C, 8K, 1044C, 10K 7-7
Disassembly, Frame Tilt Control Valve
1. Note locations of fittings and plugs installed in valve body ports.
Remove all fittings and plugs. Drain any residual oil into a suitable
container.
2. Lift rubber boot (Item 2) from flange (Item 9) and slide it up lever
assembly (Item 1).
3. Remove one of the circlips (Item 7) from pivot pin (Item 8). Push pin
out of flange and remove lever assembly.
4. If rubber boot (Item 2) needs to be replaced, remove roll pin (Item 4)
and pull lever assembly out of cam (Item 3). Remove plastic cable tie
(if installed) from around top of boot. Slide boot off lever assembly.
5. The lever assembly (Item 1) is a sealed unit and service is limited to
replacing the plastic knob.
6. Note position of flange (Item 9) on valve body (Item 20). Remove four
(4) capscrews (Item 5) and washers (Item 6). Remove flange.
7. Remove guide assemblies (Item 10). Plunger (Item 17) may now be
removed from guide (Item 12). Be careful not to scratch the plunger.
The seals in the guide may be removed by first removing spreader
(Item 15).
8. Remove two (2) spool assemblies (Item 18) and springs (Item 19).
Take care not to scratch the spools.
9. Before removing ported guides (Item 24) be aware that the guides
were factory-installed with thread sealant. Removing ported guides is
very difficult and results in severe contamination of the valve body
porting. If the guides must be removed, extra care must be given to
cleaning and flushing the valve body. All traces of thread sealant must
be removed from the guide and valve body threads.
Cleaning and Inspection, Frame Tilt Control Valve
1. Thoroughly clean all parts, except for the lever assembly, in clean
solvent and dry with compressed air. Do not immerse the lever
assembly (Item 1) in solvent. Solvent can become trapped in the
assembly and will be difficult to remove.
2. Pay particular attention to the porting in the valve body. Flush valve
body with clean solvent and use compressed air to dry.
3. Inspect each spool (Item 18) for scratches and damage. Scoring on
the spool may also indicate damage to the ported guides (Item 24). If
damage is evident, replace with new parts. Check fit of spools in
ported guides. The spools must fit snugly with no sticking. A stuck
spool can cause unintentional operation of a hydraulic circuit.
Excessive play or sticking means that the spool and its ported guide
must be replaced.