Ever notice how an oil leak attracts dirt? As the leaking continues the oily mess grows. One of the primary sources for leaks is a poor fitting connection. Leak-free hydraulics has always been desired but few know that the solution has been available for some time. Manufacturers are slowly eliminating problems which could have been prevented over 20 years ago.
Oil leak prevention has a friend. Flat Face O-Ring (FOR-Seal™) fitting and hose ends will virtually stop all connector leaks. FOR-Seal™ style fittings and hose ends from 1/4″ – 1″ are rated to 6,000 psi.
Note: Just because the fittings and hose ends are rated to 6,000 psi, this in no way allows for 6,000 pounds of pressure to be used in most hoses in use today. Each hose has its own pressure rating which, in most cases, is substantially lower than 6,000 psi.
What is a Flat Face O-Ring connection?
FOR-SEAL™ fittings have a recessed o-ring groove machined into its face and
the matching hose end has as its mating surface a smooth flat surface to which is
drawn up tight to the fitting by a nut, similar to a JIC female hose end. The o-ring
provides a better seal than the traditional pipe thread.
There are two types of o-rings used in FOR-Seal™ fittings. Most o-rings used are 90-durometer buna-nitrile that can handle temperatures of 250°F. The second type is Viton o-rings, which can handle temperatures of up to 400° F.
A number of advantages can be realized when using FOR-Seal™ type fittings and hose ends. Because the hose end is tightened to a mating adapter by a swivel nut, the hose is free to be positioned where wanted and not subject to kinks and alignment problems at installation.
Metal to metal connections stretch with repeated uses such as pipe threads and JIC fittings, but the FOR-Seal™ fitting is renewed each time the connection is broken by the insertion of a new o-ring. FOR-SEAL™ fittings also have a higher tolerance for vibration than metal to metal connections.
Let’s look at some “rule of thumb” pressure definitions:
Low pressure – up to 1,250 psi
Medium pressure – 1,250 – 2,000 psi
High pressure – 2,000 – 3,000 psi
Very high pressure -3,000 – 5,000 psi
Late model tractors and heavy equipment have had 2,500 psi hydraulic systems for over 25 years and newer machines will have system pressures that are or will be higher in the days ahead. The days of tapered pipe fittings will be coming to an end on newly engineered products from large corporations if in fact they have not already made the switch to some type of o-ring seal fitting and hose connection.
What the military pioneers, soon follows for the private sector. As technology advances, higher pressures are expected on equipment coming from manufacturers. Newer types of sealing techniques are here. We need to be ready to meet the challenges when the need for repair or replacement of parts arises.
FOR-Seal™ is a product name for a hose end configuration using an o-ring sealing method, trademarked by Dana Corporation.