2010/04/30 A Rework Procedure Improves the Seal Assembly Performance in Hydraulic Cylinders on Cat Products {7562} Caterpillar


A Rework Procedure Improves the Seal Assembly Performance in Hydraulic Cylinders on Cat Products {7562}
`
2010/04/30 [SEPD1119]
HYDRAULIC SYSTEM
CYLINDER GP
2010/04/30 A Rework Procedure Improves the Seal Assembly Performance in Hydraulic Cylinders on Cat Products {7562}
AVSpare Products:
  • All
  • ReferenceApplied Failure Analysis, REHS2811, "Hydraulic Cylinder Seal Failure Analysis"

    The hydraulic cylinders may make noise during cylinder movement. The noise may be due to uneven surface on the outside diameter of the nylon seal ring. The uneven surface must be reworked to maintain proper contact with the inside diameter of the cylinder assembly so that the noise can be reduced. The nylon seal ring is a part of the seal assembly that is used in the piston.




    Illustration 1g02149531

    Cross-section of seal assembly

    (1) Nylon seal ring

    (2) Seal expander

    Use the following rework procedure in order to correct the uneven surface on the outside diameter of the nylon seal ring:

    Note: 100 percent clean-up of the nylon seal ring is not required. The nylon seal ring must only be reworked circumferentially. It is not recommended to rework the nylon seal ring in an axial direction. Reworking the nylon seal ring in an axial direction will promote oil bypass. This procedure can be applied to any nylon piston seal ring. This procedure should not be used on piston seals that use the polyurethane or PTFE ring.

    1. Use a sheet of 120-grit emery paper attached to a sanding block in order to rework the nylon seal ring.



      Illustration 2g02149290

      Outside view of the nylon seal ring

    1. Lightly drag the sanding block over the surface on the outside diameter of the seal in a circumferential pattern as shown in Illustration 2.



      Illustration 3g02149520

      Removal of high spots from sanding

    1. The sanding removes the high spots and high corners on the seal ring so that the uniform contact surface is obtained. The sanding of the nylon seal ring also provides a better surface for lubricant to be carried on between the seal ring and the inner stage seal surface.

    1. The nylon seal ring should be reworked lightly until the continuous contact can be seen around the circumference.



      Illustration 4g02149291



      Illustration 5g02149524

    1. After sanding the surface on the outside diameter on the nylon seal ring the surface should be as shown in Illustration 4 and Illustration 5.

    Information System:

    C9.3 Tier 4 Final Engines Diesel Particulate Filter Has Changed Regeneration Interval
    MP15, MP20, MP30 and MP40 Multi-Processors Operation
    374D Excavator Machine System Specifications Bucket Linkage - WB Family
    Installation and Operation of the Caterpillar Diesel Particulate Filter (DPF) and the Diagnostic Module for Non-Road Machine Applications (Non-California Applications) {108F, 1091, 7490}
    336E Excavator and 336E MHPU Mobile Hydraulic Power Unit C9.3 Engine Supplement Engine Rear Mount - Remove and Install
    374D Excavator Machine System Specifications Upper Frame
    336E Excavator and 336E MHPU Mobile Hydraulic Power Unit Machine Systems Bucket Cylinder - Remove and Install
    Installation of the 300-1191 Auxiliary Hydraulic Lines Gp {5057}
    374D Excavator Machine System Specifications Stick Cylinder
    349F and 352F Excavators Machine Systems Duo-Cone Conventional Seals - Install
    Procedure to Replace the Counter Balance Spool for 307C/D and 308C/D Excavators {4050}
    2010/08/13 A New Counter Balance Spool Helps Reduce Travel Drift for 307C/D and 308C/D Excavators {4050}
    VHC-30, VHC-40, VHC-50 and VHC-60 Hydraulic Crushers Swivel - Remove and Install
    VHC-30, VHC-40, VHC-50 and VHC-60 Hydraulic Crushers Hydraulic Cylinder - Remove and Install
    VHC-30, VHC-40, VHC-50 and VHC-60 Hydraulic Crushers Hydraulic Cylinder - Remove and Install
    VHC-30, VHC-40, VHC-50 and VHC-60 Hydraulic Crushers Speed Control Valve - Disassemble
    VHC-30, VHC-40, VHC-50 and VHC-60 Hydraulic Crushers Hydraulic Rotator and Hydraulic Crusher Housing - Separate
    336E Excavator and 336E MHPU Mobile Hydraulic Power Unit C9.3 Engine Supplement Engine and Main Hydraulic Pump - Remove and Install
    VHC-30, VHC-40, VHC-50 and VHC-60 Hydraulic Crushers Swivel - Assemble
    VHC-30, VHC-40, VHC-50 and VHC-60 Hydraulic Crushers Gerotor Motor - Assemble
    VHC-30, VHC-40, VHC-50 and VHC-60 Hydraulic Crushers Gerotor Motor - Disassemble
    VHC-30, VHC-40, VHC-50 and VHC-60 Hydraulic Crushers Swivel - Disassemble
    VHC-30, VHC-40, VHC-50 and VHC-60 Hydraulic Crushers Speed Control - Remove and Install
    VHC-30, VHC-40, VHC-50 and VHC-60 Hydraulic Crushers Hydraulic Cylinder - Remove and Install