Évaluations - 5, GPA: 3.2 ( )

Fabricant : Bush Hog Taille : 2.82 mb Nom Fichier : Langue d'enseignement:

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 anti-cavitation check valve is stuck or not seating properly - clean anti-cavitation valve carefully, being sure that checks move freely and seat properly, or replace cartridge. See item 30 next. 30. Problems involving the control valve proper: This valve is a precision device and is not intended 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 reservoir oil supply is kept clean and only factory supplied packings are used in cylinder repair. Everything must be clean and free of dirt during the oil line removal and replacement, and during any cylinder work. Pages 19 and 20, Valve Repair-Disassembly, explain the procedure to follow for valve repair. 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. 18 VALVE REPAIR - DISASSEMBLY RETAINER BACK-UP WASHER SCREW 5/16-18 x 3/4 SPOOL COLLAR RETURN SPRING SPRING COLLAR LOCKWASHER O-RING SEAL RETURN SPRING SPRING COLLAR SCREW, 5/16-18 x 3/4 SPOOL COLLAR LOCKWASHER SCREW, 1/4-20 x 7/8 RETURN SPRING DETENT BALL FOLLOWER BONNET RETAINING RING STOP COLLAR DETENT BALL SCREW, 1/4-20 x 7/8 U-CUP SEAL FLOAT SLEEVE RETAINING SLEEVE DETENT SPRING O-RING SEAL LOCKWASHER FLOAT BONNET ASSEMBLY STANDARD SPRING CENTERED BONNET ASSEMBLY Figure 11 Replace Center Section Assemblies: Note: For the purpose of these instructions we will consider the section containing the MAIN RELIEF VALVE as the left side of the valve. 1. Remove control valve from the backhoe. 2. Thoroughly clean the exterior of the valve before beginning disassembly procedures. 3. Since the valve will be assembled in the same order, each section should be marked numerically so that they can be reassembled in the same sequence. 4. Mount the valve vertically in a vise to facilitate disassembly and assembly. 5. Remove the 3 tie rod nuts from the right end section, using a thin-wall socket. 6. Valve sections can now be removed by sliding the sections along the tie rods. 7. Thoroughly clean the O-ring counterbores and the ground surfaces of each section. Place O-ring seals, ordered as a kit, in proper counterbores. For better sealing it is recommended that all O-rings, used in the counterbores, are replaced with new parts. 8. Replace the sections on tie rods with the O-ring counterbores facing the right end of the valve. Be careful replacing the sections so that the section O- rings are not moved from the counterbores. 9. When all sections are assembled on the tie rods, tighten the tie rod nuts equally to 20 ft. lbs. torque, NO MORE - NO LESS, or spools may bind and stick. Replacing Spool Seals: Note: For the purpose of these instructions we will consider the control handle side of the valve as the FRONT, and the opposite side as the BACK. 19 1. Remove control valve from the backhoe. 2. Thoroughly clean the exterior of the valve before beginning disassembly procedures. 3. At the BACK of the valve remove all bonnet assembly parts which are connected to the spool. Keep parts in the order of disassembly. See Figure 11 for the parts involved in the make-up of the bonnet assembly. IMPORTANT: DO NOT remove the spool from the valve. The seals can be replaced externally. Prevent spools from turning or moving by inserting a screw driver through the clevis slot, or by running a rod through the pin hole and using the rod as a handle. DO NOT hold the spool with a wrench. This will destroy the finish. 4. At the BACK of the valve, remove seal retainer, back-up washer, and spool O-ring seal, or retaining sleeve,bonnet O-ring seal and spool U-cup seal. 5. Thoroughly clean counterbores. 6. Install new seals: A. Spring-Centered Bonnet Assembly Only: Lightly oil new O-ring seal. Slide O-ring seal over valve spool and insert in seal counterbore. Replace back-up washer and seal retainer. B. Float Bonnet Assembly Only: Replace retaining sleeve on valve spool. Lightly oil new U-cup seal. Slide U-cup seal over valve spool being careful to orient seal as shown in Figure 11. Install new O-ring seal in bonnet counterbore. 7. At the BACK of the valve replace bonnet assembly parts, reversing the order in which they were disassembled in step 3. Use 12 ft. lbs....

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