Maintenance Of Hydraulic Pump; Disassemble, Main Oil Pump; Inspection And Repair - Yale A7S1 Service Manual

8000 YRM 2199
1. CLEVIS
2. DUST RING
3. BAFFLE RING
4. SEAL RING
5. O-RING
When tilt spool valve is pushed forward, the high-
pressure fluid enters from the bottom of the cylinder,
pushing the the piston forward and allowing the mast
to mast to tilt forward by 6°. When spool valve is pulled
backwards, the fluid enters from the front end of
cylinder body, to push the piston until the mast tips
backwards by 12°.

MAINTENANCE OF HYDRAULIC PUMP

Disassemble, Main Oil Pump

NOTE: For the following procedures refer to Figure 55
and Figure 56.
1. Clamp the pump gently on a vice stand after
cleaning. Remove the bolts (item 12).
2. Detach pump cover (item 1) and seal rings (items,
8, 9, 10, and 11).
3. Remove the front-end cover (item 7) and seal
rings.
6. GUIDE SLEEVE
7. BEARING
8. O-RING
9. PISTON ROD
10. CYLINDER BODY
Figure 48. Tilting Cylinder
4.

Inspection and Repair

Clean disassembled metal parts with hydraulic fluid.
Inspect, repair, or replace according to following
procedure.
Inspection of Pump Body
1.
11. SEAL RING
12. WEAR RING
13. PISTON
14. SEAL RING
Remove bearings and gears (items 3-6) from
pump body. Bearings may be removed by
pressing the gears, if it is difficult to remove them.
The gear pump is designed so the gear rotates
along the inner surface of the pump body. Under
normal wear its wear area shall not exceed a
length 1/3 of the inner edge of the pump body. If it
reads ½ length, it indicates that the bearing and
gear shaft are worn out. When size at "X"
exceeds 39.180 mm (1.542 in.), replace the pump
body. See Figure 49.
Hydraulic System
51