(k) Install wheels as follows:
(1.) Install the grease seal and inboard bearing cone onto the axle.
(2.) While aligning the disc-carrier with the wheel, carefullyplace the wheel over the axle until
the wheel race engages the inboard cone. (3.) Install the outboard bearing and torque the axle nut to 50 foot-pounds. (4.) Loosen the nut to 0 foot-pounds, andwhile rotating the wheel, retorqueto 25 foot-pounds.
NOTE: If, after torquing the axle nut, the cotter pin cannot be installed, advance the nut an additional 30 degrees to align the safety holes.
(I) Install bearing cup and retaining plug.
EFFECTIVITY: 040-999
4000
Jan 10/9032-40-00
PIPERAIRCRAFT
PA-42-720(AdvancedTrainer)
MAINTENANCEMANUAL
A. Wheel Assemblies (continued)
4. Inspection of Main Wheel Assembly
(a)
Visuallyinspect 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 IIIis 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)
InspectO-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 halveflange 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 DRYBEARINGS.
(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.
(c)
Lightly saturate new or reused grease seal felts with SAE 10 oil before installation.
NOTE: Never paint bearing cup working surfaces.
NOTE: Do not soak grease seal felts with oil.
EFFECTIVITY:
040-999 PAGE5
32-40-00Jan 10/90
PIPERAIRCRAFT
PA-42-720(AdvancedTrainer)
MAINTENANCEMANUAL
A. Wheel Assemblies (continued)
NOTE:For detailed repairprocedures, referto B.F.G. Manual.
-B
Thebolt holes maybe reamed
to 0.345 max.dia.typical of
bothwheel halv es. 0.040 radius
or chamfer both sides
PIPERAIRCRAFT
PA-42-720(Advanced Trainer)
MAINTENANCE MANUAL
A. Wheel Assemblies (continued)
6. Repair of Main Wheel Assemblies (refer to 32-40-00 Figure 801)
Repairs to the main wheel assembly are limited to blending out small nicks, scratches, gouges, areas of slight corrosion, and replacing of parts which are cracked or badly corroded.
NOTE: At each tire change, visually inspect wheel halves for corrosion, especially at the bead seat area (tire contact surface) and tie bolt holes. Corrosion can be removed with 400 grit emery cloth and touched up with Dow No. 19 solution or equivalent. Prime all treated areas with one coat urethane primer. A protective finish is put on wheel halves at the factory. If corrosion cannot be removed by sanding down to bare metal within limits (shown in 32-40-00 Figure 801 for BFG wheel), wheel half must be taken out of service.
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