How to install Brake Line
Cutting to Length
Determine the length of the brake line required, using stiff wire, solder, tape
measure or the old brake lines as a pattern. Cut to the required length using a
tubing cutter. Do not distort the brake line by over-tightening it in the cutter. File
the ends to ensure it's square and remove burrs from the inside and outside
edges. Blow filings out of the brake lines.
Selecting the Brake Line Nuts
If not reusing the original nut, be sure new nut matches with diameter, thread
pitch, length, non-threaded lead, etc. Long style nuts are preferred for high
vibration applications. Install nut on brake line before flaring.
Flaring Brake Lines
The appropriate single, bubble or double flare can be formed, using a good
quality flaring tool such as the 007 brake line flaring tool. Serrated grips should
not be used. Ensure that the dies grip the tube securely without deforming the
tube section or denting its surface. Check that the flare is of the correct profile
for the unit and component involved and that is has been formed symmetrically
on the tube axis.
Installing the Brake Lines
Bend the nutted and flared tube carefully to shape, so that it will fit easily into
position. Bends should be smooth and have as large a radius as possible. For
tight bends on the larger sizes, a rolling die bending tool should be used. A
minimum bend radius of three times the tube diameter is recommended. Tubing
should not be kinked or strained into position. It should emerge cleanly from the
nut without bearing against it. Lubricate the threads and the bearing surface of
the flare with anti-seize compound without twisting the tube. Do not over-tighten the
nut.
Tightening Torque
As a general rule from finger tight, continue tightening the nut until you feel it
draw down tight, then tighten approximately 1/6" turn more. Do not over-tighten.
Installation Support
All brake lines should be supported at regular intervals along their length, using
steel or plastic clips, each attached firmly to the body or chassis of the vehicle.
When brake lines follow axle casings or suspension arms, which can induce
vibration of the tube, it is essential to secure tightly. Tie wraps work well to
secure to rear axle housings. Clips should be spaced at intervals of approximately
12 to 13 inches but no farther apart than those used for steel brake lines.