Assembly And Installation Of Wheel Brake Assembly; Removal Of Brake Master Cylinder; Disassembly Of Brake Master Cylinder; Cleaning, Inspection And Repair Of Brake Master Cylinder - Piper Navajo Chieftain PA-31-350 Service Manual

NAVAJO CHIEFTAIN SERVICE MANUAL
7-55. ASSEMBLY AND INSTALLATION OF WHEEL BRAKE ASSEMBLY. (Referto Figure 7-19 or 7-
20.)
a. If anchor bolts have been removed, they should be reinstalled as follows:
I. Support anchor bolt in a holding fixture. (Refer to Figure 7-22, Step B.)
2. Align cylinder body over anchor bolt. (Refer to Figure 7-22, Step C.)
3. Using a suitable arbor press, apply pressure on the spot face directly over the anchor bolt. (Refer
ito Figure 7-22, Step D.)
4. Install washer and nut; torque nut to 60 inch-pounds.
b. Lubricate O-rings with fluid MIL-H-5606 and install. Slide the pistons in cylinder housing until flush
with surface of the housing. For pistons with friction rings (see Figure 7-20) check pilot bores and chamfers for
burrs and nicks, remove before installing piston. Place piston in bore, rotate to seat friction ring and lightly tap
into place. If piston does not seat, alternately tap and rotate: If considerable effort is required, remove piston
and inspect pilot bore and piston tail for damage. Rework, if necessary and repeat above procedure.
c. Apply a small amount of thread lube to the threaded area of the inlet and outlet fittings and
install in cylinder.
d. Slide the pressure lining plate (6) onto the anchor bolts (16) of the housing.
e. Slide the housing assembly on the torque plate (11) of the gear.
f. Install the backing plates (10) and secure with self-locking cap bolts (1); torque to 60
inch-pounds.
g. With brake line disconnected push the linings as far apart as possible. In this position there should
not be excessive drag or the tolerance between the disc and lining should not be greater than noted on
Sketch A of Figure 7-19 or Figure 7-20. . Assemblies falling outside the limits noted should be removed and
rechecked for lining and brake disc minimum thickness. The wheel should rotate freely, if binding occurs,
check axle nut to insure proper seating. If rubbing occurs check back plate assembly and pressure plate
assembly linings to be sure that linings are fully seated.
h. Connect the brake line to the housing and bleed brakes.
7-56. BRAKE MASTER CYLINDER.
7-57. REMOVAL OF BRAKE MASTER CYLINDER.
a.
Disconnect the brake lines from the cylinder and place a protective cover over the line openings
to prevent contamination of the system.
b. Remove the cylinder from the pedal assembly by removing the clevis pin at the piston rod and
the bolt at the top of the cylinder body.
7-58. DISASSEMBLY OF BRAKE MASTER CYLINDER. (Refer to Figure 7-23.)
a.
The internal parts of the brake master cylinder (1) may be removed by removing the snap ring
(16) from the annular slot at the lower end of the cylinder. Pull the complete piston assembly from the
cylinder.
b. Slide the packing gland (15), O-ring (13), washer (11) and spring (10) from the piston rod (12).
c. The piston valve assembly may be removed by first removing the self-locking nut (2) from the
piston rod (12). This will allow the piston (8) with component parts to be removed.
7-59. CLEANING, INSPECTION AND REPAIR OF BRAKE MASTER CYLINDER.
a.
Clean the cylinder parts with a suitable solvent and dry thoroughly.
b.
Inspect the interior walls of the cylinder for scratches, burrs, corrosion, etc.
c. Inspect the general condition of the fitting threads of the cylinder.
d. Check the piston and valve for scratches, burrs, corrosion, etc.
e. Repairs to the cylinder are limited to polishing out small scratches, burrs, etc. and replacing valve
washer seal and O-rings.
Reissued: 9/23/80
LANDING GEAR AND BRAKE SYSTEM
2F12