4-13. 6-NFR DISTRIBUTING VALVE (cont)
CLEANING, INSPECTION, AND REPAIR (cont)
Clean, inspect, and repair slide valve (18) and graduating valve (19) by the following:
Check that valves are not scratched, scored, or damaged. Replace damaged valves.
Use a micrometer and measure slide valve (18) thickness from the bottom of the graduating valve seat.
Replace slide valve if thickness is less than 0.549 inch (13.944 mm).
Use a depth gage and measure depth of 1/8-inch (3.2 mm) slots in slide valve (18). Replace slide valve if
depth of slots is greater than 0.093 inch (2.362 mm).
Use flat gage and gage thickness of graduating valve (19).
If graduating valve (19) is within gage limits, use lapping compound and lap slide valve to slide valve seat by
Condition the valve by rubbing slide valve against seat several times with lapping compound. Remove
burrs and rough surface marks.
Compressed air used for cleaning purposes will not exceed 30 psi (207 kPa). Do not direct
compressed air against skin. Use goggles or full face shield.
Use compressed air and remove foreign particles from cavities.
Regage graduating valve (19).
Check that piston is not bent. Use a micrometer and measure diameter of two guides on piston. Rep
lace piston if
diameter is greater than 1.733 inches (44.02 mm).
Use triple valve oil and lubricate slide valve bushing.
Use pneumatic grease and lubricate O-rings, O-ring grooves in spool valves, and bushings into which spool valves
enter. Use a clean wiping rag and remove excess lubricant.
Lubricate rubber check valves by placing them in a box with dry graphite and -- shaking the box. Remove check
valves. Wipe excess graphite off on a piece of wiping rag.