Vacuum System Service Tips - Piper PA-44-180 SEMINOLE Maintenance Manual

DISTRIBUTION.

VACUUM SYSTEM SERVICE TIPS.

The following information is intended to acquaint field service personnel with important vacuum system
service procedures on those components which are serviced by removal and replacement. These items include
hoses, clamps, gyro filter, vacuum regulating valves and vacuum gauge.
1. Hoses and Clamps:
A. These items should be examined periodically and inspected carefully whenever engine maintenance
activities cause hose disconnections to be made at the pump, regulating valve, gyros and or vacuum
gauge.
B. The ends of the hoses should be examined for rubber separation and slivers of rubber on the inside
diameter of the hoses. These slivers can and do become detached. If this happens, the vacuum pump
suck these loose particles and eventually ingest them. This can lead to a need for premature pump
service.
WHEN REPLACING ANY OF THE THREADED FITTINGS, DO NOT USE
PIPE DOPE OR ANY OTHER ANTI-SEIZE TAPE OR COMPOUND. THE
AIRBORNE AND SIGMA-TEK(EDO-AIRE) FITTINGS ARE CADMIUM
P L ATED TO AVOID THE NEED FOR ANY OTHER ANTI-SEIZE
M ATERIALS. THE REASON FOR THIS CAUTION IS TO PROTECT THE
PUMP FROM INGESTING ANY FOREIGN MATERIALS THAT COULD
CAUSE PREMATURE SERVICE. REFER TO STEP TWO OF THIS
SUBJECT PARAGRAPH FOR INSTALLATION OF FITTINGS.
C. Hose clamps and fittings should be replaced when broken. damaged or corroded.
2. Fitting Installations:
A. Make sure all air lines are clean and free of foreign material. Do not permit oil, grease. pipe
compound, or any foreign material to enter the ports prior to installation of fittings.
B. With the proper fitting selected apply teflon tape as follows, refer to consumable material~ chart for
product acquisition.
DO NOT USE THREAD LUBE IN FITTINGS OR IN PORTS. THE USE OF
THREAD LUBE CAN CAUSE CONTAMINATION WHICH SHORTENS THE
LIFE EXPECTANCY OF THE GYRO AND CAN CAUSE PREMAT U R E
FAILURES. ANY EVIDENCE OF THREAD LUBE WILL CREATE A
WARRANTY VOID CONDITION.
(1). Carefully lay the teflon tape on the threads of the fitting allowing one thread from the end of the fitting
to be visible.
(2). Hold in place and wrap in the direction of the threads so the tape will remain tight fitting is installed.
Make sure to apply sufficient tension while windings to assure that tape forms into thread grooves.
One full wrap plus 0.5 inch overlap is sufficient.
(3). With the wrap completed. maintain tension on the tape and pull the tape in the direction of the wrap.
The resulting ragged edge is the key to securing the tape. If sheared or cut tape may loosen.
PIPER AIRCRAFT
PA - 4 4 - 1 8 0 / 1 8 0 T
AIRPLANE MAINTENANCE MANUAL
— CAUTION —
— CAUTION —
2K12
3 7 - 11 - 0 0
Page 37-05
Revised: May 15, 1989