Wheel Brake Assembly Cleaning, Inspection And Repair; Wheel Brake Assembly Assembly And Installation - Piper PA-44-180 SEMINOLE Maintenance Manual

CLEANING, INSPECTION AND REPAIR OF WHEEL BRAKE ASSEMBLY.
1. Clean the assembly with a suitable solvent and dry thoroughly.
2. Check the wall of the cylinder housing and piston for scratches, burrs, corrosion, etc., that may damage "O"
rings.
3. Check the general condition of the brake bleeder screw and lines.
4. Check the brake disc for wear, grooves, scratches or pits. Minimum service thickness of Disc 164-22A used
on Wheel Assembly 40-90A is .345. A heavy duty brake and wheel assembly is optional. The minimum
disc thickness of Disc 164-46 used on heavy duty Wheel Assembly 40-120 is .405. A single groove or
isolated grooves up to .030 of an inch deep would not necessitate replacement, but a grooving of the entire
surface would reduce lining life and should be replaced. Should any cracks be found to exceed a length of
.80 inch or a depth of .210 inch in the 164-46 disc assembly, replace the disc. If the crack depth is not
measurable, replace the disc if the crack length exceeds .400 inch. The disc should be immediately replaced
if any crack extends into the welded seam between the flange and cup.
5. The riveted type lining may be removed from the backing plates by drilling out the old rivets using a 5/32
drill. Install a new set of linings using the proper rivets and a rivet set that will properly stake the lining and
form a correct flair of the rivet. The snap-on type lining used on optional heavy duty assemblies may be
removed by prying loose with a screwdriver or a thin flat wedge. Install the snap-on type by positioning
onto the pins and applying pressure to snap into position.
Standard duty brake linings should be conditioned by performing a minimum of six
light pedal effort braking applications from 25 to 40 mph. Allow the brakes to
partially cool between stops. This conditioning procedure will cure the resins in the
brake linings, yet will not cause the material to become carburized due to excessive
heat.
Replacement brake linings used on optional heavy duty brakes should be conditioned
by performing 3 consecutive hard braking applications at 45 to 50 mph. Do not allow
brake discs to cool substantially between stops. This will wear off any high spots and
at the same time generate sufficient heat to glaze the surface of the metallic linings
Once the linings are glazed, they will provide many hours of maintenance free service.
ASSEMBLY AND INSTALLATION OF WHEEL BRAKE ASSEMBLY. (Refer to Figure 32-15.)
1. Lubricate the piston "O" ring(s) with fluid MIL-H-5606 and install on piston(s). Slide the piston in cylinder
housing until flush with surface of housing.
2. Slide the lining pressure plate onto the anchor bolts of the housing.
3. Slide the cylinder housing assembly on the torque plate of the gear.
4. Position the lining back plate between the wheel and brake disc. Install the bolts and torque to 40 inch-
pounds to secure the assembly.
5. Connect the brake line to the brake cylinder housing.
6. Bleed the brake system.
PIPER AIRCRAFT
PA - 4 4 - 1 8 0 / 1 8 0 T
AIRPLANE MAINTENANCE MANUAL
— Note —
2H14
3 2 - 4 4 - 0 5
Page 32-46
Revised: May 15, 1989