1997/10/06 Caterpillar

Higher Capacity Fan Belts Now Used{1350,1356,1359}

Usage:

Challenger 55 (7DM) Agricultural Tractors

Reference: Service Magazine; October 21, 1996; Page 2; "Improvements to Engine Cooling Capability Summarized."

Description of Change: A fan belt set with a larger cross section is now used. The mean belt section is increased from 9.52 mm (.375 in) to 12.7 mm (.49 in). The crankshaft and the fan pulleys are also increased in diameter to allow more belt wrap. The speed ratios have not changed.

Adaptable To: The new pulleys and belts are effective with the Challenger 55 (7DM991) Agricultural Tractor. The larger belts and pulleys are adaptable to all earlier Challenger 55 (7DM1-990) Agricultural Tractors. See the referenced article for previous cooling system improvements and the following chart for parts required.

143-3291 High Ambient Pulley Group.

Caterpillar Information System:

1997/10/06 Fuel Tank Filler Screen Available{1273,1710}

1997/09/29 Handling Instructions For Water Pumps{1361}

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

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

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

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

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

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 Hose Assembly Change To The Front Brake Breather Lines Group{4257}

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

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 New Cylinder Groups And Tube Assemblies For Stabilizers With Flip Over Pads{5468}

1997/10/06 New Cab Mount Reduces Vibration{1710}

1997/10/06 New Fan Drive Absorber Increases Service Life{1358}

1997/10/06 New 100 Amp Alternator Now Available{1405}

1997/10/06 Shaft Seal Leaking In Implement Pump Groups{5070}

1997/10/06 Rotated Cylinder Cap Changes Location Of Hydraulic Line To Protect Line On Blade Lift Cylinder Group{5057,5102}

1997/10/06 New Cab Positioning Procedure For 24H Motor Graders{7301}

1997/10/06 New Differential Lock/Unlock Indicator Light Now Used With H-Series Update{7450,3264,3270}

1997/10/06 Improvements Made To H-Series Motor Graders{7475,1408,1429,3073,7304,7309,7450,7451}

1997/10/06 New Special Edition Is Available For 784B Tractor; 785B, 789, 789B, 793, 793B, and 793C Off-Highway Trucks{0374}

1997/10/06 New Special Edition Is Available For 768C, 772B, 776C, and 776D Tractors; 771C, 771D, And 775D Quarry Trucks; 769C, 769D, 773B, 773D, 777C, And 777D Off-Highway Trucks{0374}

1997/10/06 Resistor Harness Reduces Fan's Speed Sensor Faults{1408,1356,1350,1000}

1997/10/06 Orifice Plate Can Be Removed From 8X-0234 Oil Cooler Lines Group In 793 And 793B Off-Highway Trucks{4257,1365}