夏延飞机维护手册 Cheyenne IIIA PA-42-720 AMM 2(61)

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7. Replacementof Wheel Bearing Cup
(a) Remove bearing cup as follows:
(1.) Heat wheel sub-assembly in boiling water for 30 minutes or in an oven not exceeding 80°C (150°F) for 20 minutes. (2.) Remove sub-assembly from heat and remove bearing cup.
NOTE: The bearing cup must be loose enough to fall out of bearing bore after heating the wheel sub-assembly and inverting it. If the cup does not drop out, use an arbor press or tap evenly from the bore with a fiber drift pin. Be careful not to damage wheel half.
(b) Install bearing cup as follows:
(1.) Place wheel sub-assembly in boiling water for 30 minutes or in an oven not exceeding 149°C (300°F) for 30 minutes. Chill bearing cup on dry ice. (2.) Remove wheel half from heat source. Dry chill bearing cup thoroughly. Coat contacting surfaces of cup with zinc chromate primer or paste. (3.) Install chilled bearing cup into heated wheel sub-assembly. Tap into place evenly with a fiber drift pin.
NOTE: The bearing cup must be installed while the primer or paste is still wet.
EFFECTIVITY:

040-999
32-40-00Jan10/90

PIPEFAIRCRAFT
PA-42-720(AdvancedTrainer)
MAINTENANCEMANUAL

A. WheelAssemblies(continued)
8. RemovalandDisassemblyofNoseWheel(B.F.Goodrich)(referto 32-40-00Figure402)
(a) Placeairplaneon jacks (referto7-10-00).
(b)Todismountnosewheel,removeaxlenut, and boltandaxleplugs.Taptheaxleoutof the wheelassemblyandforkusinga 1 7/16inchODtube.
(c) Flexforkenoughto allowthewheelandwheelspacersto clear theforkassembly.
(d)Todisassemblethewheel,deflatethe tire andbreaktirebeadsawayfromthe flanges bypressingwithheelsofthehandsor a tirepress.
(e) Removenuts, washers, andtiebolts from thewheel.Separatewheelhalves,removethetire,andremovethevalvestemassembly,if installed.
NOTE: Bearingcupsare press fittedintothe wheel halvesandmustnotberemoved,unless replacementis necessary. If cups areto be replaced,heatwheelhalf to 275° to 300°F andpressoutthecupswitha plug. Supportwheelhub while removingcups.
(f) The wheel bearingand seal areremovedbytappingoutevenlyfromtheinsidewith a brass drift. Becarefulnotto damage thebearingcage.
Bearing 
WheelHalf 
BearingGrease  -Retainer, 
Seal  Grease 
Retainer,  Seal 
Grease 
Seal 
WheelHalf 
Grease Seal  Nut 
NoseWheelAssembly (B. F. Goodrich3-1076) 
Figure 402 
EFFECTIVITY: 
PAGE  8 
Jan10/9032-40-00 

PIPERAIRCRAFT
PA-42-720(AdvancedTrainer)
MAINTENANCEMANUAL

A.  Wheel Assemblies (continued)
9. Assembly and Installation of Nose Wheel (B. F. Goodrich) (refer to 32-40-00 Figure 402)
(a) If cups are removed,reinstallas follows:
(1.) Heat wheel halves to 275° to300°F.Cool cups to 0°F.
(2.) Support wheel hub, paintthe inside diameterof the hub with zinc chromateprimer,and press the cupsinto the wheelhalf.
NOTE: The wet zinc chromate primerlubricates parts to be pressedtogetherand assists in preventing galvanic corrosion betweenparts.
(b)
Reinstall valve stem and balanceweightsif removed.

(c)
Lubricatepackingwith grease (MIL-G-3545Cor equivalent). Installin the wheel half packing groove.

(d)
Installtire and join the two wheel halves. Apply a generous coat of thread component (MIL-T-554)to threadsof bolts, faces of washers, and bearing face of nuts. Using the same procedure, retightenall nuts and torque to specification given on the wheel.

NOTE: Do not use an impactwrench to apply final torque. Use a preset handtorque wrench only.

(e)
Inflate tire (refer to 6-00-00. Chart 1) and test for leakage.

(f)  
Repack wheel bearings with grease (MIL-G-3545C) and lubricate cups. Place bearingsin wheel assembly. Installgrease seals.

(g)
Installwheel and spacers in fork and insert axle. Refer to parts catalog for proper spacers requiredfor particular tire installed.

(h)
Adjustaxle bolt to allow wheel to turn freely with no side play.

10. Inspectionof Nose Wheel Assembly (B. F. Goodrich)
(a)
Onthe bolt head radius or shank, magnafluxbolts for cracks, breaks,and surface blemishes.

(b)
Inspect wheel halves for cracks and breaks (particularlythe bead seat, tube well, and web junctionareas) with dye check or Zyglo.

(c)
Visually inspect all metal parts for pitting, corrosion,cracks,breaks, uneven wear, and other surfacedefects.

(d)  
Inspect packing sealingsurfacesfor smoothness.

(e)
Inspect packing for pits, cuts, and other defects. Replaceas necessary.

11. Cleaningof Nose Wheel Assembly (B. F. Goodrich)
(a)
Cleanmetal parts in solvent and air dry thoroughly.
　
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