Piper Cherokee LANCE, Service Manual

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PIPER CHEROKEE SIX / LANCE SERVICE MANUAL
IX - INSTRUMENTS 03/27/08
2J18
SECTION IX
INSTRUMENTS
9-1. GENERAL.
The instrumentation in the Cherokee Six is designed to give a quick and actual indication of the attitude,
performance and condition of the airplane. Maintenance, other than described in these sections, shall be
done by the instrument manufacturer or an authorized repair station.
The two types of instruments have been classified in this section as non-electrical and electrical. The first
part of this section will pertain to maintenance and troubleshooting of all the instruments and their
systems which depend on non-electrical sources for their operation. The remaining portion of this
section is directed to maintenance and troubleshooting of all the electrically operated instruments.
NOTE: The original equipment A.C. Sparkplug and Stewart Warner engine gauges and sending units are
no longer available. See Piper Service Spares Letter No. 406 and the Parts Catalog, P/N 753-689,
if replacement is required.
9-2. NON-ELECTRICAL INSTRUMENTS.
9-3. VACUUM SYSTEM.
9-4. VACUUM SYSTEM AND GYRO PRESSURE SERVICE TIPS.
The following information is intended to acquaint field service personnel with a means to diagnose
vacuum system service symptoms on those components which are serviced by removal and replacement.
These items include hoses, clamps, gyro filters, vacuum regulating valves and vacuum gauges.
a. Hoses and Clamps:
1. These items should be examined periodically and inspected carefully whenever maintenance
activities cause hose disconnections.
2. Ends of hoses should be examined for rubber separation and slivers of rubber on inside
diameter of hoses. These slivers can and do become detached. If this happens, the loose
particles will migrate throughout the system and may eventually contribute to a failure.
3. Replace old, hard, cracked or brittle hose. Sections of the inner layers may separate.
4. Ensure hoses are clear and clean by blowing them out with shop air. Remove from aircraft as
required.
CAUTION: DO NOT WIGGLE HOSE FROM SIDE TO SIDE DURING INSTALLATION.
WIGGLING COULD CAUSE PARTICLES TO BE CUT FROM INNER WALL
OF HOSE WHICH CAN LEAD TO DAMAGE OF OTHER COMPONENTS.
5. Where hose clearance is tight, making it difficult to reinstall it onto a fitting or barb, spray the
fitting or barb with silicone. Let dry, then install hose by pushing it straight on.
CAUTION: WHEN REPLACING ANY THREADED FITTING, DO NOT USE PIPE DOPE,
THREADLUBE, OR TAPE. USE ONLY SILICONE SPRAY, LETTING IT DRY
BEFORE ASSEMBLY.
6. Hose clamps and fittings should be replaced when broken, damaged or corroded.