Service and Repair Manual

AN 01-25CN-2

PARAGRAPH 1

   22. Lay the strut down on a bench horizontally with the Schrader plug up. Remove the plug and fill the cylinder with hydraulic oil (Spec. 3586) while extending the piston, until oil flows over the plug hole. Screw a pressure gage into the plug hole and insert the strut in a vertical press. Apply a pressure of 2800 p.s.i. and allow the strut to remain under this pressure for ten minutes. Inspect the oleo strut for leaks, especially around the solder joint, packing gland nut, and metering pin.

   23. If the pressure test shows no leaks, drain the hydraulic oil. If the packing has been replaced, the oleo assembly should be run in on a machine that will move the piston in and out through at least half its total travel, a minimum of 500 cycles. The strut must be fully serviced with fluid and air before running in. This servicing may be accomplished as follows:

   Push the piston into the cylinder as far as possible and stand the strut in a vertical position. Fill the strut with hydraulic fluid (Spec. 3586) until it over. flows and replace the Schrader plug loosely. Place the oleo strut in the machine and cause the strut to be extended and retracted several times to eliminate air trapped in the strut. Remove the strut from the machine and check the fluid level. If additional fluid is added, repeat the procedure outlined above each time fluid is added, until the proper fluid level is obtained. Inflate the strut to 208 psi. pressure with a high pressure hand pump. Do not use compressed air. Replace the strut in the machine and run in a minimum of 500 cycles.

   24. After the strut has been run in, assemble the scissor links. Be sure that the links are thoroughly clean and that the bushings are not worn or scored. Replace badly worn or scored bushings. When bush. ings are replaced it will be necessary to drill a new grease passage in the bushings to align with the grease passage on the scissor link which is equipped with a Zerk fitting. Coat the surfaces of the bushings and bolts with Mobilgreaft "Zero" and install the scissor links on the piston and cylinder lugs. Insm the bolts, snug up the nuts, back them off one castellation, and install the cotter pins. It is very important that the bolts are not drawn up tight to avoid binding of the bushings. Periodic inspection and greasing of the scissor links are required to assure satisfactory operation of the parts at all times.

   25. Install the axle housing and axle assembly and inse" the two through bolts. Turn up the nuts tightly and install cotter pins.

   26. Install the pinion gear with shims as on the original installation. These shims are sweat-soldered in place. Slip the segments into place and install the four bolts and the support, making sure that the support is installed on the same side of the cylinder as the scissor link lugs.

   27. Install the four segments, two facer plates, and the lower trunnion halves. Install the eight cap screws and the attachment fitting. Draw the cap screws up tightly.

   28. Install the side brace on the lower trunnion and safety the nut with a cotter pin.

   29. Slide the upper trunnion, with the bevel gear and wing fittings attached, onto the cylinder.

   30. Slide the trunnion cap onto the plunger bolt and install the plunger nut. Take up the nut with a socket wrench and safety the nut with a cotter pin.

   31. Reverse the oleo strut in the wooden block clamp and place the axle in a vertical position. Install the brake shoe and torque plate assembly on the axle and install the six attaching bolts. The oleo strut is now ready for lubrication before installing on the wing. Force Mobilgrease "Zero" through all the Zerk fittings with a grease gun until grease oozes out of the joints. Test the trunnions to see whether they revolve freely.

   (d) TO INSTALL THE OLEO STRUT ASSEMBLY ON THE WING.

   I . Raise the oleo strut to the wing and guide the fittings on the upper trunnion into the fittings on the wing. Insert the attaching bolts, tighten the nuts, and safety with cotter pins.

   2. Attach the side brace fitting to the wing, or the lower trunnion lug to the oleo strut if it was originally disconnected at this point.

   3. Attach the upper retracting links to the retracting arms and insert the assemblies into the wing