Plumbing 101: Part 8

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With this installment of Plumbing 101, we’ll complete the assembly of Earl’s UltraPro hose. This will also wrap up our fuel system plumbing series. To rewind a bit, UltraPro hose is based around a special Teflon (PTFE) inner liner that is impervious to all known fuels, oils and coolants used in today’s high performance racing and street applications. The UltraPro Polyester Braid hose we’re using here is up to 67% lighter than traditional rubber hose with stainless steel braid. Meanwhile, UltraPro Stainless Steel Braid hose is up to 37% lighter than traditional rubber hose with stainless steel braid. It’s also very flexible and has a low coefficient of friction, which obviously helps with fluid flow through the hose.

When working with this hose, it’s a good idea to have some spare olives on hand. The reason is, re-used olives will diminish the pressure rating of the hose and can cause seepage. Once a hose is assembled, you should never loosen a socket (for the rest of the fitting). If you must disassemble the socket, you must disassemble the hose, and the process must be repeated from the beginning with a new olive.

If for some reason you have to disassemble the sockets from the hose, Earl’s Performance offers the following advice:

• Lightly grip the hose end body in a vise and use a wrench to remove the hose end body.

• Next, clamp the vise onto the hose one inch away from the socket. This will destroy the section of hose crushed by the vise.

• Use a wrench to turn the socket and twist the hose until it stops. With a quick motion, further rotate the wrench, snapping the socket loose from the olive.

• Remove and reform the hose to round and disassemble the hose end components.

In the photos that follow, we’ll wrap up our look at assembling UltraPro hose and hose ends. It’s not difficult and can be done at home. Check it out:

Once the olive has been threaded a little past the end of the hose, the hose can be cut to square it up with the olive. We recommend using a box cutter with a sharp blade. Cut the hose flush with the olive, being careful not to dig into the olive. Make sure, when trimming and trueing up the convoluted hose (once threaded through olive), that a minimal amount only is used. Too long of a trim can result in the hose-to-braid ratio being unequal. Excess braid can interfere with the assembly process. NOTE: An attempt at cutting the hose square without the aid of the olive will result in a bad cut, leaving that part of the hose useless.

At this step, the olive should be fully flush with the hose. If the hose is below the face of the olive, rotate the olive clockwise slightly until no part of the hose is below the face.

You can now remove the Teflon tape and pull the braid slightly over the olive.

Apply a light coat of Earl’s Assembly Lube onto the fitting threads along with the nipple, then carefully work the braid toward the hose end. On short hoses, make sure the braid is not working away from the opposite end. If the braid is loose on the hose after both hose ends are assembled, the hose will likely fail at low pressure. Ensure none of the braid gets caught between the socket and body threads during assembly.

Once the olive is pressed against the body of the fitting as far as it will go, pull the socket over the olive and begin to thread the socket by hand clockwise onto the body, being careful not to cross the thread.

After the first couple threads have been fully engaged, use an aluminum AN fitting wrench to lightly tighten the hose end. However, be very careful not to over-tighten. Earl’s notes that standard wrenches have longer handle lengths that allow too much torque on the lightened UltraPro hose-ends.

Reposition the fitting in the vice as shown here. Be careful so that you do not crush the socket. While tightening the fitting, hold the hose with your hand. This ensures that the liner does not turn while tightening.

While tightening the socket, pay careful attention to the torque being applied. When the seal (the socket’s compression on the convolutes) is correct, you will feel the torque required to rotate the socket suddenly increase. Stop turning the socket at this point. This may not happen until the gap is closed. If so, this is acceptable. Repeat this process for the other hose end.

Here’s the finished hose assembly. By the way, it can be pressure tested using the same process we outlined with Perfom-O-Flex hose (using Earl’s pressure testing kit). Earl’s suggests you test at 1.5 times the maximum working pressure of the application (for example, fuel system). Polyester braided hose from -6 AN through to -16 AN can be tested to a maximum of 250 PSI; -20 AN hose to a maximum of 125 PSI.