Piper Arrow IV Turbo Maintenance Manual page 89

TIRE BALANCE.
Proper balancing is critical for the life of aircraft tires. If a new tire is balanced upon installation it will
usually remain balanced for the life of the tire without having any shimmy or flat spots, and an inexpensive
balancer can be made that will balance almost any tire for light aircraft. Refer to Chapter 91 for balancer
details. Balance the tire as follows:
1. Mount the tire and tube (if one is used) on the wheel, but do not install the securing bolts. Install the
wheel bearings in the wheel; then, using the -7 bushings, -6 spacers, and -5 nuts, install the wheel-tire
assembly on the -8 pipe. Secure the -5 nuts finger tight so that the wheel halves touch each other. Be sure the
bolt holes are aligned. Insert the -4 axle through the -8 pipe and place the wheel in the center of the balancer.
Make sure the axle is only on the chamfered edges of the balancer and that it is at 90° to the sides of the
balancer.
2. Release the tire. If it is out of balance it will rotate, coming to rest with the heaviest point on the
bottom. Tape a 1/2 ounce patch across top center of the tire. Rotate the tire 45° and release it again. If the tire
returns to the same position, add a 1 ounce patch and again rotate the tire and release it. Continue this
procedure until the tire is balanced.
3. When balance is attained, put a chalk mark on the sidewall directly below the patch. Use one mark for
each half ounce of weight needed. Mark the valve stem location on the tire and the opposite wheel half to
assure reassembly in the same position. Remove the wheel from the balance stand, break it down and clean the
inside of the tire with toluol. Apply a coat of patch cement to both the patch and the inside center of the tire in
line with the chalk marks. When the cement has dried, install the patches making certain they are on the
centerline of the tire and aligned with the chalk marks on the sidewall. Burnish the patches to remove trapped
air, etc.
4. When reassembling the wheel, powder the inside of the tire. Mount the tire on the valve side of the
wheel in the same position it was in when it was balanced. Install the other wheel half, aligning the chalk
marks. Install the bolts and tighten to required torque, then air the tire and recheck the balance. The wheel
should not be more than 1/2 ounce out of balance.
HYDRAULIC SYSTEM.
The general condition of the hydraulic pump and landing gear actuating cylinders should be checked.
Ensure that there are no leaks and that the line fittings are tight. The cylinder rods are to be free of all dirt and
grit. To clean the rods use an oil soaked rag and carefully wipe them. All the hydraulic lines should also be
checked for leaks, kinks, and corrosion. Check the tightness of the attachment fittings.
The gear back up extender actuator assembly is located beneath the rear seat and should be checked to
determine that it is operating properly. The diaphragm shaft may be operated by hand to make sure that it is
free to fluctuate and that the actuating arm and its components are operating freely. Check the pressure housing
assembly for cracks, breaks, or fatigue. Check to ensure that the hydraulic valve and fittings are free of leaks.
Repair and check procedures for the hydraulic pump, cylinders and various components may be found in
Chapter 29 of this manual.
PIPER AIRCRAFT
PA-28RT-201 / 201T
*MAINTENANCE MANUAL
1D17
12-20-11
Page 12-10
December 1, 1978