Hydraulic Conductors and Fittings

A hydraulic conductor, or line, is what moves fluid in a hydraulic system, analogous to a wire in an electrical system.
Similarities exist between electrical and hydraulic systems in heavy-duty mechanical applications.

Nominal size and pipe Outside Diameter (OD) are important considerations.
Reference charts are used to ensure proper replacements.
Inside Diameter (ID) and OD comparisons are vital when replacing components, ensure correct chart usage.

Thread sealants such as dope or Teflon tape are commonly used.
Dope is sometimes preferred over tape because tape can bunch up.
Thread sealant isn't recommended for high-pressure hydraulic systems; pipe connections should be used for air, grease, etc.
Steel-type fittings rated for hydraulics don't rely on thread sealant; they seal via interference between the threads as the joint is tightened.
Be cautious when using different pipes and fittings; copper fittings are not suitable for hydraulics; steel fittings rated appropriately must be used.
Thread sealant is recommended for National Pipe Thread (NPT) pipe connections.
National Pipe Thread Fuel (NPTF) or dry seal connections, the flanks make contact first.
Roots and crests engage first in NPTF, eliminating spiral clearances.

Nipple: Short connection between components or fittings.
T: Used to make parallel connections from a single pipe.
90-degree elbow or L: Used to change direction.
Other degree elbows (e.g., 60, 45 degrees) exist depending on routing requirements.
Unions: Facilitate the joining of two pipes with an external nut, preventing the need to turn the pipe for connection or disconnection.
It's crucial to select the right fitting (swivel or solid connection) for the application.

Hose sizes are often referred to using "dash" numbers (e.g., dash 4 hose).
Dash numbers relate to the outside diameter; for example, a dash 4 hose is 1/4 inch OD, or 6.35 mm.
Charts provide wall thickness and inside diameter (ID) information.
Hydraulic hoses have important information printed on them, including pressure ratings.
Changing hose size affects system pressure, potentially causing restrictions or pressure decreases.

It's essential to provide accurate information when ordering or building hoses.
Many places use hose build sheets with part numbers and specs.
Original Equipment Manufacturers (OEMs) like John Deere may provide build specs.
Hoses usually have a stamped part number or tag for identification.
Understanding outside diameter, wall thickness, and inside diameter is crucial.
The "dash" number refers to the outside diameter

More versatile than steel pipe because it can be bent to fit different applications.
It offers less flow resistance.
Adapters, flared fittings (JIC 37-degree fitting), nuts, and sleeves might be required.
Refer to manufacturer's specifications for proper installation and usage.

Typically flexible, used where bending is required rather than steel tubing.
Hose presses with different die cages are used for creating hoses.
A typical hydraulic hose has an oil/weather-resistant cover, separating layer, synthetic rubber, and reinforcement braids.
Steel reinforcement braids can be dangerous if exposed.
Reusable type connectors are becoming more popular, but permanent or crimp style hoses are also used.
When building hoses, it's important to know the machine, setting, cage, and crimps.
Over or under crimping can affect the hose diameter and cause failures.
Reusable connectors come in different types like pipe thread, male JIC flare, female swivels, split flanges, and ORB.
Refer to charts and know the pressure ratings when replacing hoses.

Reusable connectors with press-on-type sleeves are available.
Hose building is a skill that requires attention to orientation and measurement.
Incorrect hose orientation or length can cause installation problems.
Straight hoses without angles are easier to work with.
Low-velocity flow in a straight pipe is streamlined; fluid particles move parallel to the flow direction.
A gradual change does not upset the streamline, nor does a gradual change in direction. An abrupt change causes turbulence. Heat is lost and so is an abrupt change in direction.

Used in cooler climates to prevent high oil viscosity.
Submersible hydraulic oil heaters are available with thermostatic control and a heating element.
These heaters keep the oil warm during startup, similar to a radiator.
A heat gun can be used to measure temperature differences in the cooler.
The flow direction of oil into the cooler, with air passing through before returning to the tank, is important.