Loss Of Steering May Occur Without Notice On Certain Challenger 45, 65D, 75C, And 85C Agricultural Tractors Caterpillar

Loss Of Steering May Occur Without Notice On Certain Challenger 45, 65D, 75C, And 85C Agricultural Tractors

Usage:

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Caterpillar: Confidential Yellow

NOTE: This Program must be administered as soon as possible. When reporting the repair, use "PI1299" as the Part Number, "7751" as the Group Number, "56" as the Warranty Claim Description Code and "T" as the SIMS Description Code. Exception: If the repair is done after failure, use "PI1299" as the Part Number, "7751" as the Group Number, "96" as the Warranty Claim Description Code, and "Z" as the SIMS Description Code.

Problem

Two pins in Steering Pump Group 1274588 (CH 45) and Steering Pump Group 1274589 (CH 65D, 75C, and 85C) may fail. Failure of one of these pins may cause erratic steering.

Affected Product
Model & Identification Number

45 (1DR1171, 1DR1173)

65D (2ZJ2051)

75C (4KK2334, 4KK2335, 4KK2337-2339)

85C (9TK1889-1895, 9TK1897)

NOTE: The reference TIB included more serial numbers than are listed above.The tractors removed from the list were located at the trucking firm and reworked prior to delivery.

Parts Needed

1 - 1230537 Valve Group (CH 45)

-OR-

1 - 1266641 Control Kit (CH 65, 75, 85)

Action Required

Parts Stock

Remove all 1230537 and 1266641 Valve Groups with date codes 9606 through 9610 from Parts Stock.

Affected Product

On 1274588 Pump Groups, any 1230537 Valve Group date coded 9606 through 9610 needs to be replaced. On 1274589 Pump Groups, any 1266641 Valve Group date coded 9606 through 9610 needs to be replaced. The 1230537 and 1266641 Valve Groups should be replaced with one having date codes of 9611 or greater. Illustration 1 shows the approximate location of the date code on the valve group. The first two digits of the code represent the year and the last two digits describe the week. (Reference the Technical Information Bulletin dated March 20, 1996.)

REFERENCES

Disassembly and Assembly:

SENR8370 Page 8, Steps 1 and 2 and Page 30, Steps 92 and 93 show the displacement control valve being removed and installed on Challenger 65, 75, and 85 steering pump.

SENR8312 Page 62, Steps 1 and 2 and Page 82, Steps 92 and 93 show the same D&A instructions for the Challenger 45. Since the large and midsize steering pumps are very similar, either manual may be used for this rework.

Steering Control Adjustment

SENR8472 Page 53, Steps 1 through 7 describes the procedure for adjusting the steering deadband after installing and testing the displacement control as described below. This adjustment procedure can be used for both large and row crop tractors.

PROCEDURE

Disassembly, Assembly and Adjustment:

NOTE: The steering pump on large tractors (CH 65, 75, 85) may be reached by standing up under the cab on the right side of the tractor and reaching across to the pump on the left side. On row crop tractors, it will be necessary to remove the rear right side panel to gain access to the steering pump. Pulling a vacuum on the large tractor (CH 65, 75, 85) hydraulic tank will reduce the loss of hydraulic oil when removing the pump control.

1. Remove The Displacement Control:

Locate the displacement control valve on the top of the steering pump and remove the two hydraulic lines going into the top of the valve.Remove the six 5mm socket head bolts which hold the control to the surface of the pump.Lift the control away from the pump.

2. Install The New Control:

Exchange the hydraulic fittings from the old control to the new, being careful of dirt and paint chips.Replace the gasket, if necessary, and lower the new control valve onto the pump, ensuring that the feedback pin on the control engages with the hole in the pump link.

IMPORTANT:

The engagement of the feedback pin is critical. If this pin is not engaged, unexpected steering may occur when the tractor is started. After the control is sitting in place on the pump, check engagement by lifting the outside endof the control (the end opposite the adjustment screw - the adjustment screw is on the end of the displacement control valve toward the center of the tractor). If the end of the control lifts more than of an inch, the pin is not engaged.

When the control is in place and the feedback pin engaged, insert the six mounting bolts finger tight and slide the control toward the pump mounting flange as far as it will go (this will reduce the need for adjustment). Tighten bolts to 12 lb. ft. using a cross pattern.Connect the hydraulic lines. Be careful to keep contaminants out of the system.

3. Steering Deadband Adjustment:

NOTE: Steering "deadband" is the amount of steering wheel motion on either side of the center detent before steering movement is initiated. The amount of deadband to the right and left detent needs to be nearly equal or the steering will not feel proper to the operator.

IMPORTANT:

The steering test and deadband adjustment will require that all people and equipment are clear of the tractor and it is in a place where the tractor can be turned freely. Firmly engage the parking brake and start the engine.If sudden track movement occurs, immediately shut down the engine. It is likely that the feedback pin is not properly engaged and Step 2 must be repeated.

With the tractor operating at low idle, initiate steering in both directions several times to purge air from the system. Bring the engine to high idle and turn the steering wheel both directions. If the right to left deadband is nearly equal in both forward and reverse then no adjustment is necessary. If there is high deadband in one direction then make steering deadband adjustments according to the procedure in SENR8472 Page 53.