LiftMaster 3840 3840 Manual - Page 22

ALL ONE-PIECE DOORS 1. Assemble the Door Arm: • Fasten the straight and curved door arm sections together to the longest possible length (with a 2 or 3 hole overlap). • Make sure the garage door is fully closed. Connect the straight door arm section to the door bracket with the 5/16"x1-1/4" clevis pin. • Secure with a ring fastener. • Pull the emergency release handle, disconnecting the outer trolley from the inner trolley by pulling straight down on the emergency release handle and sliding the outer trolley back. See Figure 5. • Connect the curved door arm section to the trolley using the 5/16"x1-1/4" clevis pin and ring fastener. • When setting the up limit on the following page, the door should not have a "backward" slant when fully open as illustrated below. A slight backward slant will cause unnecessary bucking and/or jerking operation as the door is being opened or closed from the fully open position (Figure 6). NOTE: Proceed to the following page to Program the Travel Limits. Figure 4 Door Bracket Ring Fastener Clevis Pin 5/16"x1-1/4" Straight Arm Bolts 5/16"-18x7/8 Lock Washers 5/16" Nuts 5/16"-18 Curved Door Arm Figure 5 Inner Trolley Outer Trolley Door Arm Connector Hole Door Arm Closed Door Emergency Release Handle Figure 6 Inner Trolley Correct Angle Open Door Outer Trolley Door Arm Connector Hole Door with Backward Slant (Incorrect) 22