TRUCK SERVICE MANUAL
BRAKES-AIR
on the tubing and prevents collapsing the tubing when
the nut is tightened. The parts listing notes that there are
some sizes of tubing that are used only in accessory
piping systems in repairing accessory piping systems
tube supports are needed with all sizes of tubing except
1/8" O.D. if compression-type fittings are used.
Once the tubing has been connected and tightened
the sleeve has been crimped on the tubing and insert.
Since the sleeve has been compressed and distortion of
Fig. 6. Nylon Tubing assembly with Long nut
the insert may have resulted, the sleeve and inserts
should never be used the second time.
To assemble tubing ends for use with compression-
type fittings, the following steps should be followed
carefully.
1. Loosen and remove nut from fitting.
2. Pull tubing from fitting.
3. Repeat the same operations at other end of
Fig. 7. Nylon Tubing assembly with Short nut
tubing. If only one end of line needs repairing,
second end need not be disconnected if line is
long enough to permit repairing.
4. Cut the selected size of tubing to length. Be
sure to make smooth, square cuts. Either a
sharp knife or hack saw may be used.
5. Position nut on tube.
6. Position compression sleeve on tube.
*7. Insert tube support into tube.
*8. Position the tube, support and sleeve in the
fitting. Push tube in fitting until it bottoms.
9. Then install and tighten tube nut to secure
sleeve on tubing.
Fig. 8. Nylon Tubing Assembly Cross Section
10. Inspect tubing connections for air leakage. With
the tubing. and associated fittings charged to full
Nylon Tubing Special Instructions
system air pressure coat tubing lines and fittings
with soap suds to check for leakage. No
For the present this nylon tubing should not be
leakage is permissible. Leakage at a tubing
substituted in the field for any metallic tubing. In
fitting is sometimes corrected by tightening the
addition, the following precautions must be taken in the
tubing fitting nut. If this fails to correct the
use of nylon tubing.
leakage, replace the tubing fitting, tubing, or
both.
1. Do not use nylon tubing for any application which
would cause it to be exposed to temperatures
* No tube support is used with 1/8" O.D. tubing. Certain
below -40 degrees F or above +200 degrees F.
fittings used in accessory piping systems have the tube
support as an integral part of the fitting body. These
2. Do not subject nylon tubing to working pressure
fittings may be reused if no distortion of the tube support
in excess of 150 psi.
has occurred.
3. Do not use nylon tubing for frame-to-axle,
tractor-to-trailer or any similar line where a high
degree of flexibility is required.
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