1997/09/22 Caterpillar

New Piston Crown Improves Service Life{1214}

Usage:

777D (3PR),
793C (4AR) Off-Highway Trucks;
992G (7HR) Wheel Loaders;
5130B (4CS) Excavators

Description of Change: A new piston crown has replaced the former piston crown in the above machines powered by 3508B and 3516B Engines. The new piston crown has copper/aluminum bushings instead of steel backed bronze bushings. The copper/aluminum bushings have a higher fatigue strength.

Adaptable To: The new 144-0720 Piston Crown Assembly replaces the former 128-9517 Piston Crown Assembly within the 101-0829 Rod And Piston Group. The 128-9517 Piston Crown Assembly has been canceled.

NOTE: The piston crown bushings are not serviceable.

The new 144-0720 Piston Crown Assembly is adaptable back to first production of the above machine engines. The 125-2782 Piston Skirt, 122-5956 Piston Ring (top ring), 123-8216 Piston Ring (intermediate ring), and 123-4268 Piston Ring (oil ring) have not changed.

NOTE: The following lists the lube oil requirements for engines with the new 144-0720 Piston Crown Assembly:

* Use Caterpillar diesel engine oil CG-4.

* When Caterpillar DEO is not used, a multigrade API CG-4 is preferred. A multigrade API CF-4 is acceptable.

* The obsolete API specifications CC, CD, CD-2, and CE are not acceptable. The current API classifications CF, and CF-2 are not acceptable.

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NOTICE

Do not put 3500 pistons into 3500B Engines, or 3500B pistons into 3500 Engines. Serious piston and engine damage will occur.

Caterpillar Information System:

1997/09/22 Improved Piston Crown Assembly Used In The Rod And Piston Group{1214}

1997/09/22 New Kit Extends Life Of Rolling Hoses{6460}

1997/09/22 Correction To Lift Arm Repair Chart{6107,6119}

1997/09/22 Transmission Control Switches Serviceable{3171}

1997/09/22 Hydraulic Control System Improvements Reduce Retarder Response Time{1019}

1997/09/22 Larger Clamps Improve Hose Installation In 124-8216 Water Lines Group In 793C Off-Highway Trucks{7554}

1997/09/22 Additional Relay Valve Used In Automatic Retarder Arrangements To Improve Automatic Retarder Control (ARC) System Reliability{4005,4133,3120}

1997/09/22 Improved Braze Joint On Brake Oil Coolers Reduce Possibility Of Leaks{1365}

1997/09/22 Retrofit Kits Available For Rear Axle Lube And Filtration{4051,3258,3260,7601}

1997/09/22 New Differential Pinion Bearing Setting Tool And Procedure Available{3258}

1997/09/22 Four Wheel Drive All-Wheel-Steer Brakes{4250,4257}

1997/09/22 Engine Oil Filter Access Changed For Improved Serviceability And Turbo Life{1306}

1997/09/29 Strap Added To Retain Torsion Spring In Steering Control Group{4343}

1997/09/29 New Flushing Valve Group Eliminates Possible Shut-Down Of All Wheel Drive System{5050}

1997/09/29 New Cylinder Groups And Tube Assemblies For Stabilizers With Flip Over Pads{5468}

1997/09/29 Improvement To Air Conditioning Lines Group In The 793C Off-Highway Trucks For Reduced Engine Removal And Installation Time{1808,1809}

1997/09/29 Torque Converter Tubing Improvement Provides Clearance {3103}

1997/09/29 Hose Assembly Change To The Front Brake Breather Lines Group{4257}

1997/09/29 Service Manual Modules; SENR8609, "Schematic 769D Truck And 771D Quarry Truck Electrical Schematic". SENR1418, "Schematic 773D Truck And 775D Quarry Truck Electrical Schematic". These Service Manual Modules Are Found In Service Ma

1997/09/29 Sensor Group-Suspension Control Is Improved With Increased Reliability And Moisture Resistance{1400}

1997/09/29 New Hoist Cylinder Seals And End Cap Now Available For Service Repair{5102}

1997/09/29 New Metal Guards Prevent Debris From Entering Into Cab{7310}

1997/09/29 Gussets Are Added To Oil Pan Assemblies{1302}

1997/09/29 Bumper Spring Prevents Over Travel Of Handle For Pilot Valve Group{5059}