(4)
Remove fillet of sealant from top of gland nut and outer cylinder with toluene, to soften sealant, and a plastic or wooden spatula. Old sealant must be removed prior to priming and the application of new sealant when gland nut is reinstalled.
(5)
Deleted.
(6)
On airplanes with nose gear taxi light, disconnect wiring harness plug from light and tape to upper torsion link.
C. Replace Seals with Spare Seals
(1)
Jack under nose gear axle jacking point until shock strut extension is reduced to three or four inches.
(2)
Place cloth padding around shock strut inner cylinder below gland nut (8, Fig. 801) to prevent sharp edge of hole in gland nut from damaging inner cylinder in the event gland nut is accidentally allowed to slide down inner cylinder when unscrewed from outer cylinder.
(3)
Deleted.
(4)
Place drip tray to catch hydraulic fluid when gland nut is removed.
CAUTION: CLEAN ANY HYDRAULIC FLUID FROM TIRES IMMEDIATELY, SHOULD ANY SPLASH ON THEM, TO AVOID DETERIORIZATION.
(5)
Remove gland nut lock (18) on aft side of nose gear shock strut.
(6)
Use pin spanner adapter assembly to unscrew gland nut and slide nut to bottom of inner cylinder.
(7)
Slide scraper adapter (15) and rod wiper (7) down inner cylinder into removed gland nut.
(8)
Lower jack under nose gear axle slowly to extend inner cylinder until the lower bearing (6) and lower centering cam (2) is extended from the outer cylinder sufficiently to expose seals for replacement.
CAUTION: DO NOT ALLOW INNER CYLINDER TO EXTEND BEYOND MINIMUM POINT OF EXTENSION NECESSARY TO COMPLETE STEPS (9) AND ON. PISTON TUBE MAY BE PULLED FROM INSIDE INNER CYLINDER ALLOWING PISTON TUBE STEEL RING TO EXPAND AGAINST WALLS OF OUTER CYLINDER MAKING IT IMPOSSIBLE TO REINSERT INNER CYLINDER WITHOUT FIRST REMOVING PISTON TUBE. REFER TO PARAGRAPH 3.
NOTE: If difficulty is encountered in disassembly, pressurize shock strut with pneumatic pressure, not to exceed 100 psi, to force parts from shock strut for seal replacement.
WARNING: DO NOT PRESSURIZE SHOCK STRUT IN EXCESS OF 100 PSI OR PERSONNEL CAN BE INJURED AND MATERIAL DAMAGED.
500
Feb 15/73 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. 32-21-11 Page 803
(9)
Cut active static seal O-ring (17) and backup rings (1) from outer groove in lower centering cam. Use a plastic tool to prevent damage to cam.
(10)
Cut active seal (16), cut channel seal (3) or remove backup rings (3) from inner cylinder.
CAUTION: EXTREME CARE MUST BE EXERCISED AS ANY NICKS OR SCRATCHES ON INNER CYLINDER, BESIDES DAMAGE TO THE INNER CYLINDER ITSELF, WILL DAMAGE THE CENTERING CAM AND SEALS AS THEY SLIDE OVER THE DAMAGED SURFACE OF THE INNER CYLINDER.
NOTE: When cutting active seal or channel seal; use backup metal strip between seal and surface of material which seal contacts.
(11)
Slip spare static seal O-ring (4) from upper spare seal recess in lower bearing (6) and apply a coat of hydraulic oil and a light coat of petrolatum prior to installation.
(12)
Carefully stretch lubricated spare static seal O-ring only enough to install it in groove of lower centering cam (2) and install a new backup ring on each side of O-ring (Fig. 802).
NOTE: O-rings must have no twists when installed.
(13)
Slip a spare dynamic seal O-ring or seal assembly (5) from lower spare seal recess in lower bearing (6) and apply a coat of hydraulic oil and a light coat of petrolatum prior to installation.
(14)
Coat a cam seal, if installed, with petrolatum.
(15)
Slide spare dynamic seal O-ring or seal assembly up inner cylinder into offset in lower centering cam. Position cam seal immediately below dynamic seal O-ring, if installed (Fig. 802).
(16)
Slide lower bearing (6) against newly positioned cam seal, if installed, to hold it and the newly installed O-ring or seal assembly in place and slide bearing and centering cam as a unit into outer cylinder.
CAUTION: TABS ON LOWER CAM MUST BE PROPERLY MATED WITH NOTCHES ON OUTER CYLINDER OR DAMAGE WILL OCCUR.
NOTE: Lower centering cam should protrude 0.03 to 0.06 inch below lower end of outer cylinder. Check that upper centering cam and lower centering cam are aligned so that notched valley of lower cam is in line with lobe of upper cam. If centering cams are not properly aligned, conditions of step (22) cannot be met.
(17)
Slide scraper adapter (15) with rod wiper (7) into position against lower bearing.
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