Hydraulic systems.

TM 38-260

e. Gear housings. Housings that contain gear assemblies and spindles associated with most drive

mechanisms of plant equipment. Some of these housings may require an Extreme Pressure (EP) lubricant or a lubricant

similar in appearance to grease used for automobile differentials.

Grease fittings. Fittings which provide access to individual bearing assemblies for the purpose of applying

lubricants. A grease gun is normally required for charging these fittings.

g. Self-contained lubricators. These are lubricators with a built-in reservoir for which there are attached small

lubricating lines feeding various bearings and other assemblies and areas.

h. High-speed spindle housings. Housings that contain high-speed spindles are usually associated with

grinders. These spindles require a very light oil for lubrication. Some high-speed spindles are self-contained in sealed

units and therefore do not require cleaning or preservation.

Hydraulic systems. These systems are referred to as either open or closed type. The reservoirs for open

types are incorporated into the base of the machine. The reservoir for the closed type may be incorporated into the base

of the machine or attached to or mounted on the floor adjacent to the basic machine. The capacity of closed type

reservoirs may vary from a few gallons to several hundred gallons, and are referred to as "small closed type" and "large

closed type." The following is an analysis of each type:

(1) Open type. This type is subject to contamination by leakage of coolant and cutting oils into the

system. Grinding grit, shavings, and other contaminants may also infiltrate the open-type reservoirs.

(2) Small closed type, not more than 100 gallon (378.5 liter) capacity. These systems are used for

operating machine tools and small hydraulic presses. Those that are used on machine tools are subject to contamination

more than those used for hydraulic presses. Soluble-type coolant may work its way into these systems through packing

glands or on piston rods. Gum and sludge deposits are caused by breakdown and oxidation of the hydraulic oil in small

systems.

(3) Large closed type, 100 gallon (378.5 liter) or greater capacity). These systems are usually found on

large hydraulic presses. The degree of exposure to contamination is much less than that of the small type, and in most

instances, will require external cleaning only.

(4) Systems serving tracer mechanisms. These systems may also provide power for other hydraulically-

operated assemblies.

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