9-29. REPLACEMENT OF FITTINGS.
NOTE
Defueling of airplane may be required for union and/or tubing replacement.
a. If fittings show evidence of galling, or does not meet the dimensional requirements of Figure 9-8 or
continues to leak after being tightened, it must be repaired.
b. The recommended repair is to remove the leaking union and replace it using a standard AN fitting as
outlined in AC43.13-1A, paragraph 392. This will require cutting off the swaged ferrule and adding a
short length of tubing.
c. If a replacement tube and union purchased from Piper is being used, the ferrule is pre-swaged onto the
tube. Install the pre-fabricated tube as follows:
1. Apply a thread lube as recommended in step d of paragraph titled Inspection and Tightening of
Fuel Line Union Fittings to the threads of the union.
2. Carefully align the tube into the union and snug up the nut using a wrench.
3. Then using the wrench, tighten the nut one to two flats (1/6 to 1/3 of a turn).
d. If a repair is being made using a Parker-Hannifin unions and tubes without pre-swaged ferrules they
should be installed as follows:
1. Cut off the tubing at a convenient location back from the fitting.
2. De-burr the end of the tube and prepare a short length of tube to splice into the line.
3. Screw the nut and ferrule onto the union until solidly finger tight.
4. Insert the tubes into the unions, being careful to ensure proper straight alignment of the tubing and
union.
5. Using a tubing wrench, tighten the nut one and one-quarter (1-1/4) turns.
e. After corrective action has been completed, perform leak test as outlined in steps g and h of paragraph
titled Inspection and Tightening of Fuel Line Union Fittings.
Figure 9-8. Tolerances, Union Nut and Tubing Nut
Revised: 2/13/89
2F2
CHEROKEE ARROW III SERVICE MANUAL
FUEL SYSTEM
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