1999/02/08 Caterpillar

Correct Seal Usage Improves Service Life {7555}

Usage:

All Caterpillar Machines

Some earlier Caterpillar machines built in the 1970's and early 1980's used metal backed seals with tubes, hose couplings and fittings. Later, new tubes, hose couplings and fittings were introduced. The new tubes, hose couplings and fittings were designed to use rectangular seals and O-rings. The rectangular seals and O-rings provide better sealing than the metal backed seals.

Metal backed seals will not fit in components designed to use rectangular seals or O-rings. Rectangular seals or O-rings may fit in components designed to use metal backed seals, however, they WILL NOT adequately seal components designed to use metal backed seals, particularly under high pressure.

NOTE: Components designed to use metal backed seals do not have grooves necessary to prevent rectangular seals or O-rings from distorting under pressure.

Metal backed seals are no longer serviced. Some earlier Caterpillar machines may still be equipped with tubes, hose couplings and fittings designed to use metal backed seals. These earlier tubes, hose couplings and fittings should be replaced with new components that either use rectangular seals or O-rings.

NOTE: Disregard NPR information that calls for rectangular seals or O-rings as direct replacements for metal backed seals. DO NOT use rectangular seals or O-rings to replace metal backed seals in components designed to use metal backed seals.

Caterpillar Information System:

1999/02/08 Supports On Accelerated Pre-Separation Group Are Now Serviced {6934}

1999/02/08 New Battery Increases Starting Power {1401}

1999/02/08 New Feeder Control Group Available for Certain Paver Models {5643}

1999/02/08 New Valves Improve Harvester Head Service Life {0587}

1999/02/08 Supplemental Steering Self Test Changed On New D-Series Trucks {4323,4343}

1999/02/08 New Engine Pressure Sensors Available {1916,1917,1922,1923,1924}

1999/02/08 Valve Bodies Now Stress Relieved To Improve Service Life {3167}

1999/02/08 C-Series Backhoe Loaders Are Being Updated {1000,5077,6501,6504}

1999/02/08 New Inching Modulation Valve And Cable Prevents Oil Leakage {3162,3167}

1999/02/08 Acceptable Welding And Drilling Locations On ROPS Cab {7325}

1999/02/08 New Brake Air Pressure Switch Has Increased Service Life {1432}

1999/02/01 Procedure For Assembly And Installation Of Conventional Duo-Cone Seals Is Now Available{7561}

1999/02/08 New VIMS Application Guide Available {7601,0374}

1999/02/15 Spacers Now Used On 1R-1210 Midwheels {4192,4150}

1999/02/15 Special Instruction, REHS0151-01, Available For Procedure For Reinforcing And Bolting On Guide Blocks {4198}

1999/02/15 Supplement To Correct Seal Ring Positioning {3159,7555}

1999/02/15 New Right Side Platform Design Will Reduce Cracking Between Platform And Cowling {7253}

1999/02/15 Thrust Buttons For Planetary End Housing Assembly Salvage Now Available {3150,3169}

1999/02/15 Improved Brake Hubs Now Available For Certain Off-Highway Trucks {4061,4251}

1999/02/15 Bolts, Washer, And Spacers Grouped Into Fastener Groups In Engine Cylinder Head Groups {1100}

1999/02/15 Correction To Operation & Maintenance Manual SEBU6955 {0374,0375,7560}

1999/02/15 New Thrust Washer Improves Service Life Of Differential Group {3258}

1999/02/15 New Brake Disc Wear Specifications {4250}

1999/02/15 Proper Throttle Line Servicing Procedure {1269}