1978/11/20 Caterpillar

Single Coil Shut-Off Solenoid Used In Place Of Dual (Two) Coil Shut-Off Solenoid{1259}

Usage:

3406 Truck Engines, 657 and 657PP Scrapers, 777 Trucks and 776 Tractors

Description of Change: Electric shut-off solenoids with a single coil design are now used on the above models. The former solenoids were dual (two) coil design with contacts to disconnect the pull-in coil when the solenoid plunger energized (activated). Corrosion on these contacts can cause the pull-in coil to be activated at all times. The result was possible overheating of the pull-in coil and failure of the solenoid. Electric shut-off solenoids with a single coil design do not have contacts and are not sensitive (changed by differences) to adjustments made to the plunger.

Adaptable To: The new shut-off solenoids are a direct replacement for the former shut-off solenoids when all of the parts shown in the chart for a specific model are used together.

Caterpillar Information System:

1978/11/13 6V106 Post, 6V107 Stop And 6V108 Cap Now Available For Parts Service Of The 7S1100 Hose Press Arrangement{0660}

1978/11/06 New Control Cover Gives Better Control Of Exhaust Gas Recirculation System{1080,1250}

1978/11/06 Improvement Made To Solenoid In Electric Shut-Off Group{1259}

1978/10/30 6V92 Plug Socket Is Available For The Removal And Installation Of Lubricant Plugs{0612}

1978/10/30 New Fuel Injection Nozzles Are Used In 3208 Truck Engines When Equipped With EGR{1254}

1978/10/23 In The Future There Will Be A Common Warning System For All Caterpillar Machines{7450,7301,7400}

1978/10/23 5P8690 Fixture Group And 5P8691 Socket Are Available For Easier Reconditioning Of 5M4169 Cam Followers{0622}

1978/10/23 Conversion Of Testers In Earlier 1P3550 Wiring Harness Tester Groups To Use Later Test Harness Assemblies With Receptacle Connections{0650,0651,1408}

1978/10/16 Tips For Service Information Retrieval System (SIRS) Users{0374}

1978/10/16 New Transmission Mounting Group Has Improved Design For Longer Service Life{1150,3000}

1978/10/16 Modification To Rack Adjusting Tool Needed For Higher Rack Settings{0654,1257}

1978/10/16 Caterpillar Fuel Injection Test Bench Book{0374}

1978/11/20 Sender Unit For Engine Oil Pressure Gauge Moved To New Location On Truck Cab{7455}

1978/11/20 A Washer With Closer Tolerances Is Now Used In The Governor And Fuel Pump Drive Group{1288,7462}

1978/11/27 New Hose Has More Resistance To Heat{1074}

1978/11/27 New Coolant Temperature Regulator Has Flat Washer-Type By-Pass Valve{1355}

1978/12/04 Stronger Fan Adjustment Bracket Used In Fan Drive Group{1358,1359}

1978/12/04 Some Force Is Needed To Turn The Drive Shaft In All Tyrone Gear-Type Pumps; New Torque Value For Body Bolts Of Tyrone Gear-Type Pumps{5073}

1978/12/04 New Design Brace Used In 4N2905 Air Cleaner Group{1051}

1978/12/04 New Exhaust Valve Has Improved Three-Piece Construction{1105}

1978/12/04 90° Elbow Added To Air Cleaner Group To Prevent Damage To The Air Filter Service Indicator{1051,7452}

1978/12/11 New Piston Groups Use Keystone-Type Piston Rings And Have Improved Design Of Valve Pockets{1214,1215}

1978/12/11 New Electric Service Meter Used{7480}

1978/12/18 Improved Cylinder Head Gasket Now Used{1101,1201}