TM 1-1520-238-23
5-212
5.47.
MAIN ROTOR HUB LOWER PLATE PAD REPLACEMENT (AVIM) – continued
5.47.5. Inspection
NOTE
Use clean gloves (item 82, App F) when handling new pad and hub plate during inspection and
installation. Fingerprints on bonding surface of new pad and/or hub plate may impair the bonding
strength of primer and/or adhesive.
The following inspection procedures apply to the pad mounting area on hub plate.
a. Check for cracks. None allowed.
b. Check for evidence of scoring and excessive wear. None allowed.
c. Check for elongation of rivet holes. None allowed.
d. Check for pitting, corrosion, and erosion of surface finish (para 1.49).
e. Check for scratches, nicks or gouges.
(1) Remove minor surface imperfections measuring 0.005 INCH in depth or less by blending at a 10:1
transition ratio. Use pad (item 131, App F) and touch-up finish blended area (TM 55-1500-344-23).
5.47.6. Installation
CAUTION
Heat treated condition of hub plate is critical. Do not heat over 310 F (154 C) or damage will result.
NOTE
Do not allow parts to air dry for more than 4 HOURS. Heat cure must be performed within 4 HOURS
of application of primer in order for primer to achieve it’s optimum bonding properties.
a. Prime bonding surface of new pad and mating surface of plate.
(1) Apply a thin uniform coat of adhesive primer to bonding surface of new pad and mating surface of hub
plate. Use primer (item 142, App F) and brush (item 34, App F).
(2) Air dry parts for a minimum of 30 MINUTES at room temperature.
(3) Heat cure parts for 30 MINUTES minimum at 290 to 310 F (144 to 154 C).
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