Yale A7S1 Service Manual page 61

8000 YRM 2199
a. The trace of contact appears on the entire slide
inner surface, and roughness is felt when
scraped with a finger nail.
b. Crack appears around the face, and roughness
is felt when scraped with a finger nail.
c. Foreign matter is on the internal slide surface
or end face.
Most cases of failures are caused by dirty
hydraulic oil. The whole oil circuit may be
cleaned or the oil may be replaced. Some
individual cases are attributed to overloaded
safety valve, air corrosion, too high
temperature, or too low viscosity. In the case
when failures occur, leading to roughness or
severe wear on the gear shaft or the surface of
the gear, the gear and bearing shall be
replaced. The limit size for bearing
maintenance is:
Inner Diameter—19.12 mm (0.75 in.)
Total Length—26.41 mm (1.04 in.)
A. INNER DIAMETER
B. TOTAL LENGTH
Figure 51. Inner Bearing Inspection
Inspection of Gear
3. If clean hydraulic fluid is used, the gear shaft and
gear surface will not be damaged. If roughness is
felt on the surface, a crack occurs, or uneven
wear is present, replace the gear. When gear
surface is worn or discolored, it indicates that
failure has also occurred, and must be inspected.
The limit size for the axial diameter of gear shaft
is 18.94 mm (.075 in.).
A. 18.94 mm (.075 in.)
Figure 52. Gear Inspection
Inspection of Oil Seal
NOTE: For the following procedures refer to or .
a. Oil Seal (item 14) is a combination seal. The lip
on inner side of the pump shaft provides
sealing, while the lip at the outer side is for
dust resistance. Check if crack, wear, or
distortion exists on oil seal, and inspect
whether or not the rubber is elastic.
b. Replace seal rings (items 8-9) for bearing.
c. Inspect seal rings (items 10-11) for wear and
damage.
Hydraulic System
53