Toyota Camry and Avalon 1997-2000

Compression Fittings



Click image to see an enlarged view

Fig. Always use a torque wrench to properly tighten the fuel line nut

The compression fitting has a flared metal tube or a compression fitting that is surrounded by a threaded flare nut. Because the tube is flared or has a compression fitting installed, the threaded flare nut cannot be removed from the line and is considered part of the assembly.

Compression fittings are most often used when a pressure line attaches to an assembly, much like the fluid lines found at the brake master cylinder or on the inlet fuel line for the firewall-mounted fuel filter found on some Toyota Camry and Avalon models.

The compression fitting does not have a gasket or seal, rather it uses the threaded flare nut to seal the flared end of the line or a compression fitting on the line to the assembly. The flared end of the fuel line or the compression fitting is sealed between the component and the flare nut.

A compression fitting is most often found where the fluid in the line is under considerable pressure.

The flare nut is one of two types:

The externally threaded flare nut: An example of this type of fitting is most easily seen on models where the flare nut is threaded into the brake master cylinder.
An internally threaded flare nut: This type of fitting uses a compression fitting on the line and the nut threads onto a threaded fitting.

To disconnect a fuel line using a compression fitting:

  1. Hold the component that the flare nut is threaded onto securely, and using a flare nut type wrench, loosen the flare nut.
  3. Installation is the reverse of the removal procedure.
  5. When attaching a flare nut on the high pressure line, follow the below steps;
  7. Apply a light oil to the flare nut before installation. This will help insure that the threads mesh properly.
  9. Always start the nut on to the line by hand to prevent possible cross-threading.
  11. Tighten the flare nut using only a multi-sided flare nut wrench which was designed specifically for the job. Regular open ended wrenches, pliers, vise grips, etc. will only damage the nut.
  13. Torque the line nut to 21 ft. lbs. (28 Nm).

Click image to see an enlarged view

Fig. An example of an internally threaded flare nut on this fuel line. Note the use of a flare nut wrench loosen the nut while the component is held with another wrench

Click image to see an enlarged view

Fig. The open-end wrench on the left compared to a flare nut wrench on the right. The slot allows the flare nut wrench to clear the line, yet will grip the flare nut on all sides