Inspection Of Main Wheel Assembly; Cleaning Of Main Wheel Assemblies - Piper Cheyenne IIIA Airplane Maintenance Manual

PIPER AIRCRAFT
PA-42-720 (Advanced Trainer)
MAINTENANCE MANUAL
A. Wheel Assemblies (continued)
4. Inspection of Main Wheel Assembly
(a) Visually inspect bearing cups and cones for damage and wear. Be careful not to handle
bearings with bare hands.
(b) If the painted surface must be removed, be sure not to remove the magnesium surface
treatment. Abrasive blasting, using ground walnut hulls. (MIL-G-5634, Type II or III is
suggested because it does not remove surface treatment and requires masking or removal of
bearing cup.) Refer to manufacturer's service manual list in front of manual for appropriate
surface treatment.
(c) Inspect wheel halves, tie bolts, and other necessary hardware for cracks, adverse distortion,
and corrosion. The following procedure should be accomplished after the fifth and third
subsequent tire change, for a total of twenty tire changes and at each tire change thereafter:
(1.) Inspect each tie bolt for magnetic particle and torque key (MIL-1-6870 - longitudinal
magnetization) for fatigue and crack indications. Replace as necessary, especially torque
keys worn to less than 0.060 inch thickness.
NOTE: Because dye checking can stain the wheel, use it only in the tube well, especially
the bead set radius, where the tire bead heels contact the wheel.
(2.) With dye-check or fluorescent penetrant, inspect the bead seats, tube well, and especially
the web junction areas.
(d) Inspect all areas for nicks. For repair limits of the BF Goodrich wheel, refer to 32-40-00 Figure
801. Small nicks or gouges in casting must be blended out and polished with 400 grit abrasive
paper or emery cloth. Blended areas must surround damage by 1 1/2 inch.
(e) Inspect O-ring seating areas for nick or distortion. Badly distorted sections hamper O-ring
sealing characteristics and requires wheel half replacement.
(f) Inspect snap rings and grease seals for distortion. Replace grease seal fits if badly worn or
contaminated.
(g) Overheated wheel halves must be inspected for Brinell Hardness. Check hardness on wheel
halve flange areas by contacting the manufacturer for appropriate hardness value.
5. Cleaning of Main Wheel Assemblies
(a) Clean and degrease bearings and all metal parts; dry thoroughly.
CAUTION: DO NOT USE CLEANING SOLVENTS TO CLEAN RUBBER PARTS OR SPIN
DRY BEARINGS.
(b) Areas where the protective coating has been removed or shows light corrosion must be
thoroughly cleaned and repainted with one coat of urethane primer and one coat of aluminum
polyeurethane.
NOTE: Never paint bearing cup working surfaces.
(c) Lightly saturate new or reused grease seal felts with SAE 10 oil before installation.
NOTE: Do not soak grease seal felts with oil.
EFFECTIVITY:
040-999 PAGE 5
32-40-00
Jan 10/90