Repair of recoil struts at the intermediate level of maintenance is restricted to seal replacement and replacement of parts listed in the "Intermediate Maintenance Section" of the aircraft MIM or the appropriate 03 manual. The following paragraphs provide information on the disassembly, cleaning, inspection, parts replacement, reassembly, and bench testing of a strut at the intermediate level.

Disassemble the strut assembly in the order of the key index numbers assigned to the exploded view illustration provided in the appropriate 03 series accessories manual or the "Intermediate Maintenance Section" of the applicable MIM.

Before beginning disassembly, make sure that all pressure has been exhausted from the strut. Do not disassemble the inner and outer cylinder until all the pressure has been released from the strut. Disassembly of the strut before releasing all pressure could lead to serious personnel injury or loss of life.

Remove the complete air valve assembly by breaking the lockwire and unscrewing the 3/4-inch hex nut. Turn the strut over and drain the hydraulic fluid. Disconnect the torque arms (scissors). Break the lockwire and unscrew the packing nut at the bottom of the outer cylinder. Carefully withdraw the inner cylinder from the outer cylinder. Pull the metering pin and bulkhead from the inner cylinder with a smooth controlled force. Tag or keep parts together to expedite reassembly.

Thoroughly clean all parts of the recoil strut assembly, using P-D-680 dry-cleaning solvent (spray or dip) or a similar cleaning solvent. Dry thoroughly with clean, dry, compressed air, paying particular attention to all recesses and internal passages. Use the cleaning solvent in a well-ventilated area. Avoid prolonged inhalation of fumes. Keep solvent away from open flames.

Cleaned parts that normally come in contact with fluid during operation of the strut should be coated with hydraulic fluid. Depending on local conditions, it may be desirable to also coat external highly machined surfaces.

Wipe the lower bearing clean with a clean, lint-free cloth dampened with hydraulic fluid. Do not touch machined surfaces with your bare hands. Do not use compressed air to dry bearings. Clean the bearings with new cleaning solvent and dry with a lint-free cloth.

Perform a thorough visual inspection of the disassembled parts for serviceability. Packing grooves and surrounding areas should be inspected for scratches, burrs, nicks, or other roughness that might cut packings on installation or cause seal failure during strut operation. Inspect machined surfaces for mars, abrasions, gouges, grooves, scores, scratches, and corrosion. If any parts are suspected of having cracks, the part should be inspected using one of the nondestructive methods of testing.

Check all threaded parts for distorted or mutilated threads. Inspect plated surfaces for blistering, flaking, wear, or other defects.

Within the limits of practicability, check all holes for concentricity and taper, using an internal micrometer, hole gauges, plug gauges, or similar equipment. Check the angle between the piston and the axle. Check to ensure that the brake flange is perpendicular to the axle. Inspect all ports, bores, and passages for cleanliness. Place bearings next to a sensitive compass to check for residual magnetism. Bearings should be inspected for obvious damage, Brinelling (shallow indentations in the raceway), or corrosion. Rotate bearing races and check for roughness, binding, or looseness. Bearing retainers must be checked for cracks, warpage, and corrosion. Refer to the tables furnished in the applicable accessories manual or the "Intermediate Maintenance Section" of the appropriate MIM for service limits established for critical areas.

Repair or replace all parts that show evidence of excessive wear, scoring, or corrosion. Replace all parts that show wear beyond the dimensions specified in the inspection standards tables found in most 03 manuals or MIMs.

Each time the strut is disassembled, all preformed and special packings should be replaced, although they may appear to be serviceable.

NOTE: Never work on machined services with metallic tools. Always use brass O-ring tools for checking scratches and removing or replacing seals and gaskets.

Blend out minor scratches, nicks, and burrs from machined surfaces of steel parts with a crocus cloth. Use aluminum oxide abrasive cloth to polish aluminum parts. The smoothness of the repaired area must be equal to or smoother than the finish of the surrounding area. Do not attempt to remove normal wear marks from the sliding surface of the piston.

NOTE: Partial removal of plating from the inner cylinder will condemn the part from further service, pending replating of the cylinder. Portable brush-type plating equipment is available in some intermediate maintenance activities for touch-up plating of minor areas. Areas with damaged paint or other protective finishes must be restored to a serviceable condition. If any bushings require replacement, the mating bushing must also be replaced.

Reassemble the strut assembly in essentially the reverse order of disassembly. Exercise adequate precautions to ensure that dirt, dust, grit, or other foreign matter does not enter the strut during assembly. Contamination of parts can cause a definite failure. Guarding against contamination cannot be over-emphasized. Observe the torque values specified in the 03 manual or MIM. Where a specific torque value is not specified for a threaded part, tighten the part according to the standard torque values provided in the Hardware Manual, NAVAIR 011A8. Some structural repair manuals and maintenance instructions manuals also contain this information. On some parts, such as the strut gland nut, tightening should conform to acceptable shop practices and common sense, unless otherwise specified.

Lightly coat all preformed packings with hydraulic fluid. After all seals and parts are properly installed, the piston head is tightened and the retaining pins installed and staked into place. The piston assembly is inserted into the outer cylinder, and the gland nut is tightened to a snug fit, backed off two key slots, and locked in place. If the gland nut is too tight, it will result in binding of the thrust bearing. Two lock plates, positioned 180 degrees apart on the collar and gland nut, are secured with screws and lockwired to hold the gland nut in place. Use the double twist method of applying the lockwire so that tension of the wire tends to tighten the nut.