Causes and Corrections, Continued
12.Bent piston rod in cylinder - replace or rebuild the cylinder; replace damaged parts.
13.Worn or damaged rod seals on cylinder; external leaks - repack cylinder. Rebuild cylinder, replacing damaged parts as necessary.
14.Diverter valve on prime mover leaking externally or bypassing oil internally through valve to reservoir - diverter valve may need rebuilding or replacing.
15.Something jamming the swing linkage - remove interference.
16.Excessive back pressure - relieve condition. May be restriction from outlet to reservoir.
17.Paint on valve spool; sticking valve spool or scored valve spool - clean valve spool. Binding is usually caused from an over tightened plug, mounting bolt, fitting in valve body or tie rod bolt. If a plug or fitting in the valve body is leaking, do not over tighten in an effort to stop leak. This will distort body casting and cause spools to bind. Instead, the plug and fitting should be removed from valve body and be reconnected, using a new
20 ft./lbs. Never force spool, if binding occurs see item 30 at the end.
18.Oil leakage past spool seal into spool cap - remove cap. If it contains oil replace spool seal
19.Broken return springs - replace springs, see item 30 at the end and Figure 11.
20.Bent spool - replace with new spool section. See item 30 at the end.
21.Foreign particles - clean system and valve.
22.Misalignment of control handle linkage - check linkage for binding condition.
23.Spool not moved to full stroke - check travel, should be 5/16” either way, or a total of 5/8”. See item 30 at the end.
24.Relief valve setting in backhoe control valve too low or defective - relief pressure will have to be checked and corrections made. Backhoe system pressure is 2100 psi for the 665H, 2100 psi for the 765H, 2400 psi for the 865H and 2250 psi for the 965H. Relief valve may need cleaning and overhauling, or entire cartridge must be replaced. See item 30 at the end.
25.Overload relief valve in the control valve stuck open or malfunctioning - clean relief carefully but do not disturb its pressure setting as it cannot be field calibrated, or replace cartridge. See item 30 at the end.
26.Worn control valve - replace the control valve.
27.Check poppet in the control valve not holding - clean check poppet(s) carefully, being sure that it moves freely with good spring action and seats properly or replace. See item 30 at the end.
28.Damaged or worn spool seals - replace spool end seals, see item 30 at the end.
29.Ball in
or not seating properly - clean
30. Problems involving the control valve proper:
This valve is a precision device and is not intend- ed for any extensive field adjustment or repair. Field replacement parts are limited to seal kits, cartridges, valve sections and tie rods.
Replacement of these parts, the opening of check cavities and certain relief valve cavities to examine for trapped dirt, or the resetting of the main relief valve with the use of good pressure gauge, should be referred to qualified service personnel.
Dirt and shreds of packing material are the usual causes of valve malfunction. Be sure the reser- voir oil supply is kept clean and only factory sup- plied packings are used in cylinder repair. Every- thing must be clean and free of dirt during the oil line removal and replacement, and during any cylinder work.
Pages 19 and 20, Valve
The inclusion of this information and its use does not imply that the warranty will remain effective on the valve if it is tampered with during the warranty period.
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