47-10-37 LOCKHEED: (Was Service Note 8 of AD-763-3.) Applies to All Model 49 Serials Up to and Including 2071.
At periods not to exceed 500 hours, check the tightness of the inboard pair of bolts in the outboard fulcrum and the outboard pair of bolts in the inboard fulcrum of each main landing gear, using a torque wrench. A continuous record should be kept to show whether these bolts become more loose with time; therefore, these bolts should not be tightened during the periodic inspections. When any of these 8 bolts loosen to a torque wrench reading of approximately 900 inch-pounds, all fulcrum bolts (16 per airplane) should be removed, the fitting holes countersunk 0.064 x 45 degrees to accommodate the bolt head fillets, the bolts replaced and tightened to a torque wrench reading of 2,300-2,500 inch-pounds. The 500-hour inspection may then be discontinued.
(Lockheed Service Bulletin 49/SB-51, revised March 3, 1947, covers this same subject.)