Usage:
D25C, D30C, D35C, D330C, D350C, D35HP, D400 Trucks
Description of Change: New front suspension cylinder assemblies and a new relief valve assembly for the suspension control valve are used on the above articulated dump trucks. The new suspension cylinder assembly has a 102 mm (4.0") diameter rod. The former cylinder assembly has a 89 mm (3.5") diameter rod. The new relief valve assembly for the suspension control valve lowers system relief pressure.
Adaptable To: The new 6U4161 Suspension Cylinder Assembly and the 2U962 Relief Valve Assembly are direct replacements for the former 6U4385 Suspension Cylinder Assembly and the 2U1561 Relief Valve Assembly.
The new parts are adaptable to the models listed in Chart A. New parts required to install the new suspension cylinder assembly and relief valve assembly on earlier models are listed in Chart B.
Procedure To Install New Front Suspension Cylinder Assemblies And Relief Valve Assembly
1. Park the machine on hard level ground. Raise the tractor and support it with suitable stands at the front and rear of the main frame.
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Release of hydraulic oil under pressure can cause injury or death to persons on or near the machine. Be sure all hydraulic pressure is released from the system prior to loosening any fittings, hoses or other components in the hydraulic system.
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2. Remove the front wheels.
3. Disconnect the remote grease lines from the pivot pins of the top and bottom cylinders.
4. Use suitable lifting equipment and blocks to support the front axles. Disconnect the hydraulic lines from the front suspension cylinder assemblies. Plug all hose ends to keep dirt and foreign material out of the hydraulic system.
NOTE: In the following steps, the installation procedure should only be performed on one side of the machine at a time. This will prevent movement of the axle assembly.
5. Remove the former cylinder assembly from one side of the machine. Keep the pivot pins, seal faces, washers, lockwashers and bolts. Discard the O-ring seals.
6. Inspect all components for wear or damage. Replace any parts if necessary.
7. Install the new 6U4161 Suspension Cylinder Assembly in the reverse order of removal of the former cylinder assembly. Use new O-ring seals when installing the pivot pins.
8. Remove the former cylinder assembly from the other side of the machine. Install the new suspension cylinder assembly. Repeat Steps 5 through 7.
9. Remove the former 2U1561 Relief Valve Assembly from the suspension control valve. See the illustrations for the location of the valve assembly.
10. Install the new 2U0962 Relief Valve Assembly.
11. Assemble all items previously removed. Remove all stands and blocks from under the machine.
12. Lubricate the cylinder pivot pins before operating the machine. Check the level of the hydraulic oil.
Illustration 1. Location of relief valve assembly on all machines except those with suspended single axle trailers.
Illustration 2. Location of relief valve assembly on all machines with suspended single axle trailers.