Oil Level Indicator

The oil level indicator consists of a rod, known as a dipstick. The dipstick extends through a tube into the crankcase (fig. 1-40). Marks on the dipstick indicate when the crankcase is full or, if low, how much oil is needed. To take readings, you should perform the following procedure: pull the dipstick out, wipe the dipstick with a rag, stick it back in, pull it out once again, and note how high the oil level is on it. On some engines, the correct oil level is achieved after the engine has

Figure 1-40.-Oil level indicator.

cycled a few minutes. However, it is a good practice to check to make sure there is oil in the crankcase, then follow the manufacturer's recommendations.

Oil Filters

The oil filter removes most of the impurities that were picked up by the oil as it circulated through the engine. Two types of filter element configurations are in use: the cartridge type and the sealed (spin-on) type (fig. 1-41).

CARTRIDGE FILTER.- The cartridge filter element fits into a permanent metal container. Oil is pumped under pressure into the container where it passes from the outside of the filter element to the center. From here the oil exits the container. The filter element is changed easily by removing the cover from the container.

SEALED (SPIN-ON) FILTER.- The sealed (spin-on) filter element is completely self-contained, consisting of an integral metal container and filter element. Oil is pumped into the container on the outside of the filter element. The oil then passes through the filter to the center of the element where it exits the container. This type of filter is screwed onto its base and is removed by spinning it off.

Figure 1-41.-Oil filters.

HYDRAULIC FLUID

On equipment, hydraulic fluids are used for hydraulic systems that steer, lift, push, close, and so forth. Hydraulic fluids that are currently in use include mineral oil, vegetable oil, water, phosphate ester, ethylene glycol compounds, and oil in water. The three most common types of hydraulic fluids are water base, petroleum base, and synthetic base.

NOTE: Before adding hydraulic fluid in a piece of equipment, consult the operator's manual for the type of hydraulic fluid required. Using the incorrect type can contaminate the hydraulic system which requires that the system be drained, flushed, and refilled with the correct fluid.

GEAR OIL

Gear oils are used in both manual transmissions and differentials. Gear oils reduce friction and do not break down or foam at high temperatures.

NOTE: Before adding gear oil, consult the operator's manual for the type of oil required for the specific type of equipment. Mixing different types of gear oil may cause the oil to break down and not have the quality required to protect the gears.

GREASE

Grease is used to lubricate bearings, bushings, and pivot points. For inaccessible bearings, grease is applied under pressure by the use of a grease gun (fig. 1-43).

Figure 1-43.-Hand-operated grease gun.

Figure 1-42.-Filter system configurations.

Filtering Systems

Two filter system configurations are in use today: the full-flow system and the bypass system.

FULL-FLOW SYSTEM.- All the oil in the fullflow system (fig. 1-42, view A) is circulated through the filter before it reaches the engine. When this system is used, it is necessary to incorporate a bypass valve in the oil filter. This valve allows the oil to circulate through the system without passing through the element in the event that it becomes clogged. This factor prevents the oil supply from being cut off from the engine.

BYPASS SYSTEM.- The bypass system (fig. 1-42, view B) diverts only a small quantity of the oil each time it is circulated and returns it directly to the oil pan after it is filtered. This type of system does not filter the oil before it is sent to the engine.

When you are operating in dirty atmospheric conditions, grease seals out dust, dirt, and water from entering bearings and bushings.

Grease lube charts are either mounted on the equipment or are in the operator's manual. Grease lube charts state locations of grease fittings and how often the fittings should be lubricated. Over greasing of equipment blows seals and the excess grease collects sand and dirt that acts as a grinding compound on the lubricated surfaces. Under greasing allows excessive wear caused by metal-to-metal contact.

NOTE: Greasing equipment is the responsibility of the operator.

A water-resistant grease can prevent water from entering bearings and bushing joints. The grease commonly used on equipment is lithium-based. Lithiumbased grease is water-resistant and has a wide range of operating temperatures. Care should be taken to keep grease clean. Always keep the grease container covered to prevent dirt and water from contaminating it.