e. Scrape blue coating being careful not to cut braid one-half of an inch from end of lead.
—CAUTION—
New ferrules must be used and inserted under braid exactly as
stated in step f.
f. Push back braid and thread a new ferrule over wire and under braid until braid just covers
knurling. (Refer to figure 74-26.)
g. Pull lead back into cover to wedge braid between tapers of cover and ferrule.
h. Provide a back up support for cover and seat ferrule using 11-7074 Ferrule Seating Tool (refer to
figure 74-27) and a mallet. Ferrule must be driven straight into cover and fully seated.
i. Thread pre-stripped end of conductor through grommet. Place a new eyelet on conductor and
crimp per instructions given in second paragraph of Maintenance of Harness.
6. When lead being replaced is elbow type, salvage used elbow and compression springs for installation
on replacement lead. Install these and new sleeve and contact spring (refer to figures 74-28 and 74-29)
furnished with replacement lead per instructions in steps 1 thru 4.
7. Reposition clamps and brackets and replace cable ties removed earlier. Clean grommets, sleeves, and
inside of cover with methylethylketone or denatured alcohol.
8. Spray grommets and sleeves with fluorocarbon spray.
9. Prior to seating spark plug lead terminal in plug barrel use fluorocarbon spray on spark plug terminal
insulating sleeve (refer to figure 74-30) to prevent heat from sticking sleeve to spark plug barrel.
Lightly lubricate the shoulder of ferrule to minimize twisting of ferrule. (Refer to figure 74-31.) Use
Go-Jo No Lok manufactured by Go-Jo Inc., Akron, OH 44309.
10. Check cam securing screw. Tighten screw to a torque of 16 to 20 inch-pounds.
11. With all high tension terminal grommets seated against ferrules in cover, attach bottom capacitor lead
to right main breaker and then top capacitor lead to left main breaker. Position cover on magneto and
secure. Tighten cover screws to a torque of 30 to 35 inch-pounds.
12. Carefully route high tension spark plug leads away from any hot spots and sharp edges which might
cause heat damage or chafing. Check leads for proper location in clamps so when clamps are tightened
the leads will not be crushed. Leads should be taut to prevent chafing due to vibration, but not so taut
as to produce strain on leads.
13. After all leads have been properly routed and secured to engine, recheck all clamp securing screws for
tightness. Fasten coupling nuts to proper spark plugs and tighten as specified in chart 7402. Do not
allow ferrules to turn while tightening nuts.
CHART 7402. COUPLING TORQUES
Spark Plug Torque
Coupling Threads (lb.-in.)
5/ 8-24 90-95
3/4-20 110-120
74 - 21 - 00
Page - 74-24
Reissued: August 1, 1986
2J20
PIPER AIRCRAFT
PA-28-236
MAINTENANCE MANUAL
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