Clean debris from the covered port .

TB 1--1520--238--20--129

WARNING

When the APU driveshaft is rotating, maintenance personnel should stay clear of the

APU driveshaft and PTO clutch catwalk area while performing maintenance due to po-

tential catastrophic failure of the PTO clutch. Catastrophic failure of the PTO clutch can

cause extensive damage to the catwalk area and personnel injury.

(4) Clean debris from the covered port .

(a) Remove one screw from the clutch nameplate and loosen the remaining screw.

(b) Using a small probe, clean debris form the covered port area.

(c) Reinstall removed screw into the nameplate and tighten both screws.

NOTE

Insure that the covered port is not clogged with friction disk material and oil. A clogged

covered port will cause oil from the APU to build up in the friction disk area and may seep

into the duplex bearing area causing damage to the duplex bearing.

(5) Check friction disk area for oil.

(a) Remove one screw from the clutch nameplate and loosen the remaining screw.

(b) Carefully rotate name plate and gasket upward.

(c) If oil is seen inside friction disk area replace clutch IAW paragraph 9a.

(d) If no oil is noted carefully rotate nameplate and gasket back into position.

(e) Reinstall removed screw into the nameplate and tighten both screws.

(6) Check APU PTO clutch for heat discoloration. None allowed. Heat discoloration is usually

confined to the duplex bearing housing area.

(7) Check APU PTO clutch for cracks. If cracks are suspected, perform nondestructive inspec-

tion (TM 1--1520--264--23).

(8) Check APU PTO clutch for corrosion. None allowed.

(9) Visually inspect clutch mounting pad ( with PTO clutch installed) for cracks and corrosion.

None allowed.

(10)Visually inspect the duplex bearing area.

(a) Check the output bearing grease seal for damage and or metal contamination. None al-

lowed.

(b) Manually rotate the clutch output shaft in both directions. The rotating motion should be

smooth with no roughness or binding. A light amount of drag, cause by the shaft forward lip seal is to be

expected.

(11) Using flashlight visually inspect the needle bearing area.

(a) Remove the spiral retaining ring (P/N M274263112D) from the inside of the clutch output

drive shaft.

(b) Remove the aluminum plug (P/N 3886028--1) from the output shaft by inserting suitable

tool (Allen wrench or equivalent) into the inner grove of the plug, and pull the plug straight out. Discard

packing. Ensure plug is not damaged and retain for re--installation.

(c) Inspect the inside of the bearing cavity for burnt, dry, or blacken grease. None allowed.

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