Amazing deals on this Lb Drop Leg Hd Trailer Jack at Harbor Freight. Quality tools & low prices. All Coupons for LB. CAPACITY SWING-BACK TRAILER JACK: current price ($) | search the web. Price Changes: 10/09/ - $ 03/01/ -. Amazing deals on this Lb. Capacity Electric Trailer Jack at Harbor Freight. Quality tools & low prices. Assembly The Harbor freight tools trailer jack Jack requires no assembly, but care must be taken to properly mount the Trailer Jack to the trailer. Have your tool serviced harbor freight tools trailer jack a qualified repair person using only identical replacement parts. Cancel Delete. Turn the Handle 1 counterclockwise to raise the tongue of the trailer from the hitch ball. Remove the Lock Pin 13 from the Inner Tube 1 of the Jack, and turn the Handle 12 counterclockwise until the base of the Inner Tube rests solidly upon the ground surface. Before each use, verify that the Pull Pin is properly engaged in a hole of the Swing Plate 8.