Piper Cherokee Six Service Manual page 503

PIPER CHEROKEE SIX SERVICE MANUAL
9-13. REMOVAL AND REPLACEMENT.
a.
To remove the regulator valve; disconnect the three lines, remove the mounting
screws and remove the valve.
b.
Replace regulator in reverse order given for removal. Check complete vacuum system
for proper operation.
9-14. VACUUM PUMP.
9-15. GENERAL. The vacuum pump is of the rotary vane, positive displacement type. This
unit consists essentially of an aluminum housing containing a tempered sleeve in which an
offset rotor, with moving blades, is incorporated. This assembly is driven by means of a
coupling mated to the engine driven gear assembly. The pump is mounted on the accessory
section of the engine.
9-16. TROUBLESHOOTING. For troubleshooting of the pumps, refer to Table IX-I of this
section.
9-17. REMOVAL AND REPLACEMENT. The vacuum pump can be removed by the
following procedure:
a.
Remove the top portion of the engine cowling.
b.
Loosen the hose clamp and remove the hose from the vacuum pump fitting.
c.
Remove the vacuum pump by removal of the four retaining nuts. lockwasher and
plain washers.
d.
Reinstall pump in reverse order of removal, noting alignment of spline on the pump
drive with the spline on the engine drive assembly.
CAUTION
The only dry air pump mounting gasket authorized and
approved for use on the Airborne dry air pump is the
Airborne gasket B3-1-2, Piper part number 751 859. Use of
any other gasket may result in oil seepage or leakage at the
mounting surface.
9-17a. REPLACING PUMP FITTINGS.
a. The handling procedure for securing the pump while installing or removing fittings
are as follows:
1. Use two soft wood blocks in a vise to protect pump from vise jaws.
2. The pump square mounting flange must be held between the wood blocks at
right angles to the vise jaws.
3. Use only enough vise pressure to hold pump firmly.
CAUTION
Do not apply vise pressure to outside diameter or overall
length of the pump.
b. Thread lubricant, if required, should be applied sparingly to the external threads of
the fitting only. Use a powdered moly sulfide or graphite in dry form or in an evaporating
vehicle; or employ a silicone spray.
INSTRUMENTS
Revised: 12/15/80
2K11