Dowel, Pin or Piston Limits Poppet Valve Movement In Relief Valve Groups {5072}
Usage:
Most Caterpillar Equipment Using Hydraulic System Relief Valves
Description of Change: A dowel, pin, or piston has been added in the poppet valve chamber of the relief valve group to limit the movement of the poppet. Limiting movement prevents the poppet from remaining unseated when the relief valve opens.
If movement is not limited, the poppet could move above its seat. As the system pressure drops, the poppet might not return to its seated position. This could cause complete loss of hydraulic system pressure.
Typical Relief Valve Group (1) Dowel, pin, or piston.
Adaptable To: This change is adaptable to Caterpillar equipment using hydraulic system relief valves listed in the chart.
Caterpillar Information System:
1996/11/25 Blade Lift Cylinder Improved {5102}
1996/11/25 Install Additional 8Y-6388 Louver Assemblies to Improve Defogging of Cab Windshield {7304,7309,7310,7451}
1996/11/25 Rotate 8Y-6388 Louver Assemblies in Heater Group to Improve Service Life {7304,7309}
1996/11/25 Special Instruction, SEHS9926, "Installation of Turbocharger Debris Shields" Available {7263,7154,7158}
1996/11/18 New Service Parts For The Front And Rear Drive Shaft Groups For Improved Reliability{4074}
1996/11/18 Measure Vibration Of Vibratory Compactor Drums With Hand Held Meters{7471,0783}
1996/11/18 Radiator And Oil Cooler Mounting Improved{1351}
1996/11/18 New Stud Available For Gear Pump Group{5073}
1996/11/18 New Brake Adjustment Procedure For Improved Inching Ability {3162,4115,4250}
1996/11/18 Special Instruction REHS0018 Available For Installation And Adjustment Of Truck Body {7258}
1996/11/18 An Improved Suspension Control Valve Increases Ease Of Operation{7214}
1996/11/18 Stronger Screen In Hydraulic Tank Improves Service Life{5056}
1996/11/25 Inspection of Tire Stems When Using Calcium Chloride Ballast Prevents Tire Failures {4203,4231,4207}
1996/11/25 Procedure For Installing Steel Core Gasket At The Front Housing And The Flywheel Housing {1151,1157,1162}
1996/12/02 Check Turbocharger Seals If There Is A Sudden Increase In Crankcase Blowby {1052,1317}
1996/12/02 Special Instruction REHS0029 Available To Modify Radiator Support And Guard Group To Provide Cleanout Access For Radiator {1353,7272}
1996/12/02 New Retainer Screws Prevent Contact With Seat Back On Cab Recirculation Filter {7342}
1996/12/02 Ground Strap Relocated To Prevent Damage From Debris {7423}
1996/12/02 Overfill Of Hydraulic Tank May Cause Oil Leakage {7479,1460}
1996/12/02 New Front Park, Turn Lamp Is Available That Is Not Affected By Vibration {1430}
1996/12/02 Improved Relay Switch Assembly Used To Provide Increased Reliability {1423}
1996/12/02 New Drive Train Lubrication Updates {3251,3252,3253,7568,7581}
1996/12/02 New Assembly Procedure For Rotate Carriage Groups {6408,6405,6460}
1996/12/02 Improved Relay Switch Assembly Used To Provide Increased Reliability {1423}