Caterpillar 426 - Semi-Annual Maintenance

Differential Oil (Front) - Change

• Remove the oil drain plug and drain the oil into a suitable container.

• Clean the drain plug and install the drain plug.

• Remove the oil level/fill plug. Refer to Operation and Maintenance Manual, “Lubricant Specifications” and Operation and Maintenance Manual, “Refill Capacities” for oil.

• Add oil until the oil is level with the threads for the filler plug.

• Clean the filler plug and install the filler plug.

Differential Oil (Rear) - Change

• Remove the oil drain plug and drain the oil into a suitable container.

• Clean the drain plug and install the drain plug.

• Remove the oil level/fill plug. Refer to Operation and Maintenance Manual, “Lubricant Specifications” and Operation and Maintenance Manual, “Refill Capacities” for oil.

• Add oil until the oil is level with the threads for the filler plug.

• Clean the filler plug and install the filler plug.

Engine Valve Lash - Check | Check the engine valve lash after every 1000 service hours or 6 months on machines that are equipped with the following engine arrangements:

• • 122-8803 Primary Engine Arrangement

• • 122-8804 Engine Arrangement

• • 122-8805 Engine Arrangement

• • 122-8806 Engine Arrangement

Final Drive Oil (Front) - Change

• Position the oil fill/drain plug at the bottom. Remove the oil fill/drain plug and drain the oil into a suitable container.

• Position the plug hole at a horizontal position. Use the line on the final drive as a reference.

• Add oil until the oil is level with the plug threads. Refer to Operation and Maintenance Manual, “Lubricant Specifications” and Operation and Maintenance Manual, “Refill Capacities” for the oil.

• Clean the plug and install the plug

• Repeat the procedure for the other final drive.

Final Drive Oil (Rear) - Change

• Position the oil fill/drain plug at the bottom. Remove the oil fill/drain plug and drain the oil into a suitable container.

• Position the plug hole at a horizontal position. Use the line on the final drive as a reference.

• Add oil until the oil is level with the plug threads. Refer to Operation and Maintenance Manual, “Lubricant Specifications” and Operation and Maintenance Manual, “Refill Capacities” for the oil.

• Clean the plug and install the plug

• Repeat the procedure for the other final drive.

Rollover Protective Structure (ROPS) - Inspect

• Inspect the ROPS for loose bolts or for damaged bolts. Replace any damaged bolts or missing bolts with original equipment parts only

• Operate the machine on a rough surface. Replace the ROPS mounting supports if the ROPS emits a noise. Replace the ROPS mounting supports if the ROPS rattles.

Transmission Magnetic Screen - Clean

• Drain the transmission oil. Refer to Operation and Maintenance Manual, “Transmission Oil - Change”.

• Remove the magnetic strainer cover

• Remove the magnets from the housing.

• Remove the screen from the housing.

• Wash the tube and the screen in a clean, nonflammable solvent.

• Clean the magnets with a cloth, with a stiff bristle brush, or with pressure air.

• Install the magnets and the tube assembly into the magnetic screen.

• Install the magnetic screen.

• Clean the cover and inspect the seal. Replace the seal, if the seal is damaged.

• Install the cover. Tighten the cover bolts.

• Fill the transmission. Refer to Operation and Maintenance Manual, “Transmission Oil - Change”.

Transmission Oil - Change

• Remove the transmission drain plug. Allow the transmission oil to drain into a suitable container. Clean the transmission drain plug and install the transmission drain plug.

• Change the transmission oil filter element. Refer to Operation and Maintenance Manual, “Transmission Oil Filter - Replace”.

• Clean the transmission magnetic screen. Refer to Operation and Maintenance Manual, “Transmission Magnetic Screen - Clean”.

• Remove the transmission breather from the top of the transmission case. Clean the breather in clean nonflammable solvent and allow the breather to dry. Replace the breather.

• Pull the hood release lever (1) in order to open the engine access door (2) on the top of the machine.

• Remove the dipstick/fill cap and fill the transmission with transmission oil. Refer to Operation and Maintenance Manual, “Lubricant Viscosities” and Operation and Maintenance Manual, “Refill Capacities”.

• Start the engine and run the engine at low idle. Apply the service brake. Slowly operate the transmission controls in order to circulate the oil.

• Move the transmission control lever to NEUTRAL and engage the parking brake. Inspect the transmission for leaks.

• Maintain the transmission oil level within the crosshatched region on the “CHECK WITH OIL WARM” side of the dipstick when the transmission is warm. Add transmission oil through the transmission filler tube, if necessary.

• Install the dipstick/fill cap and install the engine access door.

• Stop the engine.

Wheel Bearings (Front) - Lubricate

• Raise the front wheels slightly off the ground.

• Install sufficient blocking under the frame and lower the machine to the blocking.

• Remove the nuts and both wheels.

• Remove the hub cap (1).

• Remove the cotter pin (2), nut (3), and washer (4).

• Pull the hub assembly (5) until the cone and roller assembly come out of the hub assembly. Then, pull off the hub all the way

• Clean all of the parts in clean, nonflammable solvent and allow the parts to air dry. Do not use pressure air.

• Inspect the roller assemblies for heat discoloration and for wear. Inspect the seals for damage. Replace any damaged parts.

• Make sure that the grease gets packed between the rollers and the cage on both bearings.

• Force the grease through the bearing from the large end of the rollers.

• Pack a 6 mm (0.25 inch) layer of grease between the bearing assemblies in the hub. Do not fully pack the hub with grease.

• Apply a 6 mm (0.25 inch) thick film of grease on the spindle surface.

• Install the hub, the bearings, the washer, the nut and the wheel.

• While you turn the wheel, tighten the nut (3) until a slight drag is noticed. Back off the nut to the nearest slot and install the cotter pin..

• All bearing surfaces must make contact. The wheel should turn freely within 0.025 to 0.25 mm (0.001 to 0.010 inch) end play.

• Install the hub cap.

• Tighten the lug nuts to a torque of 400 ± 40 N·m (295 ± 30 lb ft).