Piper SEMINOLE PA-44-180, Maintenance Manual

Page: 80 / 881

DRAINING BRAKE SYSTEM.
To drain the brake system, connect a hose to the bleeder fitting on the bottom of the cylinder and place the
other end of the line in a suitable container. Open the bleeder and slowly pump the hand brake lever and the
desired brake pedal until fluid ceases to flow. To drain the wheel brake unit, disconnect the line at the bottom of
the unit and allow fluid to flow into a suitable container. To clean the brake system, flush with denatured alcohol.
TIRES.
The tires should be maintained at the pressure specified in Chart 601 of Chapter 6. When checking tire
pressure examine the tires for wear, cuts, bruises and slippage. The tire, tube, and wheel should be balanced
when installed. Align the index mark on the tire with the index mark on the tube.
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 center line 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.
PA - 4 4 - 1 8 0 / 1 8 0 T
AIRPLANE MAINTENANCE MANUAL
1 2 - 2 3 - 0 1
Page 12-08
Revised: May 15, 1989
1D8
PIPER AIRCRAFT