Caterpillar Caterpillar Backhoe Loader 420E 420E

Differential Oil (Front) - Change

1. Remove oil drain plug (1) and drain the oil into a suitable container.

2. The drain plug is magnetic. Check the plug for metal.

3. Clean the drain plug and install the drain plug.

4. Remove oil level/fill plug (2).

5. Add oil until the oil is level with the threads for the filler plug. Refer to Operation and Maintenance Manual, “Lubricant Viscosities” and Operation and Maintenance Manual, “Capacities (Refill)” for oil.

6. Clean the filler plug and install the filler plug.

Differential Oil (Rear) - Change

The oil change interval should be decreased to 500 hours if more than 50% of the service hours is used for roading and loading.

Note: A qualified service person should perform the valve lash check and/or the valve lash adjustment. Special tools and training are required.

Was the valve lash check performed successfully?

If not, describe the issues encountered

Sign off on the valve lash check

Engine Crankcase Breather - Replace

Loosen the clamp (9) and remove the hose (10) from the connector (12)

Remove the setscrews (8) and remove the connector (12) from the cylinder head. Remove the gasket (13). Remove the O-ring seal (11) from the connector. Discard the gasket (13) and the O-ring seal (11)

Remove the cover (1) from the valve mechanism cover (5)

WARNING: Personal injury can result from parts and/or covers under spring pressure. Spring force will be released when covers are removed. Be prepared to hold spring loaded covers as the bolts are loosened.

Remove the screws (2). Remove the plate (3)

Remove the diaphragm (4) and the cap (6). Remove the spring (7). Discard diaphragm (4)

WARNING: Improper assembly of parts that are spring loaded can cause bodily injury. To prevent possible injury, follow the established assembly procedure and wear protective equipment.

Install the spring (7), the cap (6), and a new diaphragm (4)

Backhoe Boom, Stick, Bucket, and Cylinder Bearings - Lubricate

Position the backhoe into the service position that is shown above. Lower the bucket to the ground. Relieve the hydraulic pressure and remove the load from the greased joints.

Apply lubricant to the grease fitting (1) for the rod end of the stick cylinder.

Apply lubricant to the grease fitting (2) for the head end of the boom cylinder and the head end of the stick cylinder.

Apply lubricant to the grease fitting (3) for the rod end of the boom cylinder.

Apply lubricant to the grease fitting (4) for the boom pivot. There is one grease fitting on each side of the machine.

Apply lubricant to the grease fitting (5) for the bucket pivot pin.

Apply lubricant to the grease fitting (6) for the link.

Apply lubricant to the grease fitting (7) for the rod end of the bucket cylinder.