D250E Series II and D300E Series II Articulated Trucks Caterpillar

Towing the Machine

Usage:

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Improper hookup and towing is dangerous and could result in injury or death to yourself or others.
The towing connection must be rigid, or towing must be done by two machines of the same size or larger than the towed machine. Connect a machine on each end of the towed machine.

Be sure that all necessary repairs and adjustments have been made before a machine that has been towed to a service area, is put back into operation.

Follow the recommendations that are listed below in order to perform the towing procedure correctly.

Note: To prevent the machine from moving, place blocks under the machine wheels. This must be done before you release the parking brake.

The machine is equipped with a spring applied, oil pressure released parking brake. The parking brake is mounted in the output transfer gear case.

If the engine cannot be run, the transmission pump will be inoperable. This may prevent the release of the parking brake.

The parking brake can be released manually when there is not enough oil pressure in the system.

Refer to Operation and Maintenance Manual, "Parking Brake Manual Release".

The following towing instructions are for moving a disabled machine for a short distance at low speed.

Move the machine at a speed of 2 km/h (1.2 mph) or less to a convenient location for repair. Always haul the machine if long distance moving is required.

Do not allow an inexperienced operator onto a machine that is being towed. The operator must know the location of the machine controls. The operator must be familiar with the steering operation and with the braking operation of the machine.

Shielding must be provided on both machines. This will protect the operator if the tow line or the tow bar breaks.

Before you tow the machine, make sure that the tow line or the tow bar is in good condition. Make sure that the tow line or the tow bar has enough strength for the towing procedure that is involved. The strength of the tow line or of the tow bar should be at least 150% of the gross weight of the towing machine. This is true for a disabled machine that is stuck in the mud and for towing on a grade.

Keep the tow line angle to a minimum. Do not exceed a 30° angle from the straight ahead position.

Quick machine movement could overload the tow line or the tow bar. This could cause the tow line or the tow bar to break. Gradual, steady machine movement will be more effective.

Normally, the towing machine should be as large as the disabled machine. Make sure that the towing machine has enough brake capacity, enough weight, and enough power. The towing machine must be able to control both machines for the grade that is involved and for the distance that is involved.

You must provide sufficient control and sufficient braking when you are moving a disabled machine downhill. This may require a larger towing machine or additional machines that are connected to the rear. This will prevent the machine from rolling away.

If the machine is being towed downhill and the machine requires articulation, the steering frame locks can be removed. This maneuver will require two towing machines. One towing machine must be attached to the front of the disabled machine in order to control the tractor. An additional towing machine must be attached to the rear of the disabled machine in order to control the trailer.

Do not disengage the parking brake or remove the blocks from the wheels, until the weight of the disabled machine is held or controlled by the towing machine.

The requirements of all situations cannot be listed. Minimum towing machine capacity is required on smooth, level surfaces. Maximum towing machine capacity is required on inclines or on uneven surfaces.

Note: Consult your Caterpillar dealer for more information about towing a disabled machine.

Towing a Machine that has an Inoperable Engine

If the engine is inoperable, the transmission pump will also be inoperable. This may cause premature wear on components in the transmission and in the transfer gear. Therefore, the machine can only be towed at low speed for short distances. Do not exceed a road speed of 2 km/h (1.2 mph).

If the machine is in the straight ahead position and the machine needs towing for only a short distance, it is unnecessary for the steering system to be disabled.

If the machine is not in the straight ahead position, adjustment will be necessary. Adjust the position of the machine by using the secondary steering.

Note: The secondary steering system will only operate with a charged battery.

If the machine is not in the straight ahead position and the secondary steering is inoperable, it will be necessary to disable the steering system. This will allow the machine to articulate.

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Illustration 1	g00601475

Place a suitable container under the steering cylinder before you disconnect the hydraulic hoses. The container will catch oil when the hydraulic hoses are disconnected. Remove the hose clips that secure the hydraulic hoses to the machine frame. Reverse hydraulic hose (1) and hydraulic hose (2) on one of the steering cylinders. This will allow the machine to articulate without spilling oil.

Block the wheels securely.

Hook up the towing machine or towing machines to the disabled machine. Ensure that the combination of towing machines is enough for the towing of the disabled machine.

The parking brake must be disengaged manually if the oil pressure in the system is not enough to keep the brake disengaged.

Start the engine of the towing machine. Move the machine forward slowly in order to take the weight of the disabled machine. Remove the blocks and very slowly tow the disabled machine.

When the machine is at the required destination, block the wheels again.

Manually engage the parking brake.

Return hydraulic hose (1) and hydraulic hose (2) to the original positions.

Towing a Machine that has an Operable Engine

If the engine can be run during towing and there is no fault with the steering system, an operator can steer the disabled machine.

If the braking system is working correctly, an operator can use the service brakes to slow down the machine during towing. If the braking system is working correctly, the manual release of the parking brake will be unnecessary. The parking brake will engage when the engine stops regardless of the position of the parking and secondary brake control.

Failure in any of the following machine systems will require machine towing: