Piper Cherokee LANCE, Service Manual

Page: 208 / 854

PIPER CHEROKEE SIX / LANCE SERVICE MANUAL
VA - HYDRAULIC SYSTEM 07/15/06
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5A-3. TROUBLESHOOTING. Malfunctions in the hydraulic system will result in failure of the landing
gear to operate properly. When trouble develops, jack up the airplane (refer to Jacking, Section II) and
then proceed to determine the extent of the trouble. Generally, hydraulic system troubles fall into two
types, troubles involving the hydraulic supplying system and troubles in the landing gear hydraulic
system. Table VA-IV at the back of this section, lists the troubles which may be encountered and their
probable cause, and suggests a remedy for the trouble involved. A hydraulic system operational check
may be conducted using Figures 5A-l or 5A-2. When the trouble has been recognized, the first step in
troubleshooting is isolating the cause. Hydraulic system troubles are not always traceable to one cause. It
is possible that a malfunction may be the result of more than one difficulty within the system. Starting
first with the most obvious and most probable reasons for the trouble, check each possibility and, in turn,
by process of elimination, isolate the troubles.
NOTE: If it is found that the hydraulic pump is at fault and requires disassembly, it is recommended that
it be overhauled by an accredited overhaul facility. Pressure checks with adjustments may be
accomplished in accordance with instructions given in Paragraphs 5A-6 thru 5A-9.
5A-4. HYDRAULIC PUMP.
5A-4a. ORIGINAL EQUIPMENT PRESTOLITE PUMP
5A-5. REMOVAL OF HYDRAULIC PUMP. The hydraulic pump with reservoir incorporated is located in
the nose section of the fuselage. Access to the pump is through the access panel in the nose baggage
compartment.
a. Disconnect the pump electrical leads from the pump solenoid relays and the ground wire from the
battery shelf.
b. Disconnect the hydraulic lines from the pump. Cap the line ends to prevent contamination.
c. Remove pump by removing pump attaching bolts.
5A-6. DISASSEMBLY OF HYDRAULIC PUMP. (Refer to Figure 5A-3.) After the hydraulic pump has
been removed from the airplane, cap or plug all ports, and clean exterior of pump using a dry cleaning
solvent to remove accumulated dirt and dust. The three major components of the pump assembly are the
pump base, pump motor, and valve and gear case. These three major components should be
disassembled as follows:
a. Pump Base: Remove pump base (16) from valve and gear case by:
1. Cutting safety wire and removing bolts (17) with washers securing pump base to pump and
gear case.
2. The check valve within the pump base should be removed for cleaning purposes only. To
remove valve, cut safety wire and remove bolt, spring and steel ball. Replace O-ring at
reassembly.
b. Pump Motor: The pump motor may be removed from the pump and disassembled as follows:
1. Remove thru bolts (4) from head (1) of motor. Using a knife cut the seal coating between the
motor head and case.
2. Lift the head up from the case approximately .50 of an inch, this will allow inspection of
brushes (3) without the brushes unseating from the commutator. (Refer to Paragraph 5A-7 for
brush inspection.) The brush leads are secured to the head assembly.