9BL1-1398
The lift and tilt pilot valve is manually controlled by the operator. The lift and tilt pilot valve controls the flow of oil from the pilot system to the lift and tilt control valve. The lift and tilt control valve controls the operation of the lift cylinders and the tilt cylinder. The lift and tilt pilot valve has four valve stems. Two valve stems are required for each operation.
When a lift control lever or a tilt control lever is moved, one plunger is pushed down in the pilot valve. The plunger causes a valve stem to move downward. Pilot oil is sent to one end of a valve spool in the lift and tilt control valve. Oil from the opposite end of the valve spool is pushed out of the lift and tilt control valve. The oil flows back to the pilot valve to another valve stem. The oil then flows back to the tank through the tank passage.
Three valve stems in the pilot valve are identical. The stems are for DUMP, TILT BACK and LIFT. The LOWER stem is longer than the other three stems.
HOLD Position of LIFT Operation
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| Illustration 1 | g00495101 |
LIFT and LOWER Stems in HOLD Position. Single Lever Bucket Control. (1) Actuator (2) LIFT control shaft (3) Plunger (LOWER) (4) Plunger (LIFT) (5) Retainer (6) Retainer (7) Metering spring (8) Metering spring (9) Centering spring (10) Centering spring (11) Tank passage (12) LOWER stem (13) LIFT stem (14) Holes (15) Holes (16) Vent passage (17) Tank passage (18) Passage to LIFT valve spool (19) Passage to LIFT valve spool (20) Pump passage (21) Passage to TILT valve spool (22) Passage to TILT valve spool (FF) Supply oil (HH) Blocked oil (LL) Return oil | |
When the LIFT control lever is in the HOLD position, plungers (3) and (4) are in the same position. The plungers do not push up against actuator (1) in the HOLD position. Pilot pump oil flows through pump passage (20) and the oil is stopped by stems (12) and (13). Holes (14) and (15) are open to tank passage (11) .
RAISE Position of LIFT Operation
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| Illustration 2 | g00495109 |
LIFT Stem in RAISE Position. Single Lever Bucket Control. (1) Actuator (2) LIFT control shaft (4) Plunger (LIFT) (6) Retainer (7) Metering spring (8) Metering spring (9) Centering spring (11) Tank passage (12) LOWER stem (13) LIFT stem (14) Holes (15) Holes (18) Passage to LIFT valve spool (19) Passage to LIFT valve spool (20) Pump passage (EE) Pilot oil (FF) Supply oil (HH) Blocked oil (LL) Return oil | |
When the LIFT control lever is moved into the RAISE position, the control lever moves control shaft (2) and actuator (1). The actuator pushes plunger (4) against the force of centering spring (9). LIFT stem (13) moves down with the plunger. The oil from pump passage (20) flows through holes (15). The oil flows out of passage (19) to one end of the lift valve spool. The pressure of the supply oil on the end of the LIFT valve spool moves the spool into the RAISE position.
The oil from the chamber at the opposite end of the LIFT valve spool flows back through passage (18). The oil flows to holes (14) of LOWER stem (12) into tank passage (11) .
Oil pressure in passage (19) pushes up against LIFT stem (13) and metering spring (7). An increase in pressure within passage (19) pushes LIFT stem (13) against the force of metering spring (7). The flow of oil through holes (15) and passage (19) is now stopped. LIFT stem (13) is pushed off retainer (6) and the stem is held in a pressure modulating position. The LIFT stem keeps a balance between the pressure in passage (19) and the force of metering spring (7) .
When the LIFT control lever is released, centering spring (9) pushes up on plunger (4). Actuator (1) turns shaft (2) and the lever moves back to the HOLD position. LIFT stem (13) moves up as retainer (6) moves up. The retainer moves up as metering spring (7) expands. The oil in passage (19) can now flow through holes (15) and tank passage (11). The centering springs on the LIFT valve spool in the lift and tilt control valve move the valve spool back to the HOLD position. The extra oil from the end of the LIFT valve spool also flows through holes (15) and tank passage (11) .
LOWER Position of LIFT Operation
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| Illustration 3 | g00495115 |
LOWER Stem in LOWER Position. Single Lever Bucket Control. (1) Actuator (2) LIFT control shaft (3) Plunger (LOWER) (5) Retainer (8) Metering spring (10) Centering spring (11) Tank passage (12) LOWER stem (13) LIFT stem (14) Holes (15) Holes (17) Pump (supply) passage. (18) Passage to LIFT valve spool (19) Passage to LIFT valve spool (20) Pump passage (EE) Pilot oil (FF) Supply oil (HH) Blocked oil (LL) Return oil | |
When the LIFT control lever is moved into the LOWER position, the control lever turns control shaft (2) and actuator (1). The actuator pushes plunger (3) against the force of metering spring (8). LOWER stem (12) moves down with the plunger. The oil from pump passage (20) now flows through holes (14) out of passage (18) to one end of the LIFT valve spool. The pressure of the supply oil on the end of the LIFT valve spool moves the spool into the LOWER position.
The oil from the chamber at the opposite end of the LIFT valve spool flows back through passage (19). The oil flows through holes (15) of LIFT stem (13) into tank passage (11) .
Oil pressure in passage (18) pushes up against LOWER stem (12) and metering spring (8). An increase in pressure within passage (18) pushes LOWER stem (12) against the force of metering spring (8). The flow of oil through holes (14) and passage (18) is now stopped. LOWER stem (12) is pushed off retainer (5) and the stem is held in a pressure modulating position. The LOWER stem keeps a balance between the pressure in passage (18) and the force of metering spring (8) .
When the LIFT control lever is released, centering spring (10) pushes up on plunger (3). Actuator (1) turns shaft (2) and the lever moves back to the HOLD position. LOWER stem (12) moves up as retainer (5) moves up. The retainer moves up as metering spring (8) expands. The oil in passage (15) can now flow back to the tank. The oil in passage (18) can now flow through holes (14) and tank passage (11). The centering springs on the LIFT valve spool in the lift and tilt control valve move the valve spool back to the HOLD position. The extra oil from the end of the LIFT valve spool also flows through holes (14) and tank passage (11) .
LOWER Position With Engine OFF
When the front of the machine is lifted off the ground, there is pressure in the rod end of the lift cylinders. When the bucket is off the ground, there is pressure in the head end of the lift cylinders. The oil flows from the location with the higher pressure into the lift and tilt pilot control valve. When the LIFT control lever is moved to the LOWER position, either the bucket or the front of the machine lowers to the ground.
The oil returns to the tank and the oil pressure in the lift cylinders is released. If the bucket is off the ground, the weight of the bucket and lift arms cause the bucket to lower. If the front of the machine is off the ground, the weight of the machine causes the front of the machine to lower.
HOLD Position of TILT Operation
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| Illustration 4 | g00495101 |
DUMP and TILT BACK Stems in HOLD Position. Single Lever Bucket Control. (1) Actuator (2) LIFT control shaft (3) Plunger (LOWER) (4) Plunger (LIFT) (5) Retainer (6) Retainer (7) Metering spring (8) Metering spring (9) Centering spring (10) Centering spring (11) Tank passage (12) LOWER stem (13) LIFT stem (14) Holes (15) Holes (16) Vent passage (17) Tank passage (18) Passage to LIFT valve spool (19) Passage to LIFT valve spool (20) Pump passage (21) Passage to TILT valve spool (22) Passage to TILT valve spool (FF) Supply oil (HH) Blocked oil (LL) Return oil | |
When the TILT control lever is in the HOLD position, plungers (3) and (4) are in the same position. The plungers do not push up against actuator (1) in the HOLD position. Pilot pump oil flows through pump passage (20) and the oil is stopped by stems (12) and (13) .
TILT BACK Position of TILT Operation
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| Illustration 5 | g00495172 |
TILT BACK Stem in TILT BACK Position. Single Lever Bucket Control. (11) Tank passage (20) Pump passage (21) Passage to TILT valve spool (22) Passage to TILT valve spool (24) Actuator (25) TILT control shaft (26) Plunger (TILT BACK) (27) Plunger (DUMP) (28) Retainer (29) Retainer (30) Metering spring (31) Metering spring (32) Centering spring (33) Centering spring (34) DUMP stem (35) TILT BACK stem (36) Holes (37) Holes (EE) Pilot oil (FF) Supply oil (HH) Blocked oil (LL) Return oil | |
When the TILT control lever is moved into the TILT BACK position, the control lever turns control shaft (25) and actuator (24) in a counterclockwise direction. TILT BACK stem (35) moves down with the plunger. The oil from pump passage (20) flows through holes (37). The oil flows out of passage (21) to one end of the valve spool. The pressure of the supply oil on the end of the TILT valve spool moves the spool into the TILT BACK position.
The oil from the chamber at the opposite end of the TILT valve spool flows back through passage (22). The oil flows through holes (36) of DUMP stem (34) into tank passage (11) .
DUMP Position of TILT Operation
When the TILT control lever is moved into the DUMP position, the control lever turns control shaft (25) and actuator (24) in a clockwise direction. DUMP stem (34) moves down with the plunger. The oil from pump passage (20) flows through holes (36). The pressure of the supply oil on the end of the TILT valve spool moves the spool into the DUMP position.
The oil from the chamber at the opposite end of the TILT valve spool flows back through passage (21). The oil flows through holes (37) of TILT BACK stem (35) into tank passage (11) .
9BL1399-UP
HOLD Position of LIFT Operation
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| Illustration 6 | g00406650 |
LIFT and LOWER Stems in HOLD Position. Two Lever Bucket Control. (1) Actuator (2) LIFT control shaft (3) Plunger (LOWER) (4) Plunger (LIFT) (5) Retainer (6) Retainer (7) Metering spring (8) Metering spring (9) Centering spring (10) Centering spring (11) Detent spring (12) Detent spring (13) LOWER stem (14) LIFT stem (15) Passage to LOWER end of valve spool (16) Passage to LIFT end of valve spool (17) Pump passage (18) Tank passage (BB) Supply oil (DD) Metered oil (HH) Blocked oil (LL) Return oil | |
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| Illustration 7 | g00407142 |
LIFT and LOWER Stems in HOLD Position. Single Lever Bucket Control. (1) Actuator (2) LIFT control shaft (3) Plunger (LOWER) (4) Plunger (LIFT) (5) Retainer (6) Retainer (7) Metering spring (8) Metering spring (9) Centering spring (10) Centering spring (11) Detent spring (12) Detent spring (13) LOWER stem (14) LIFT stem (15) Passage to LOWER end of valve spool (16) Passage to LIFT end of valve spool (17) Pump passage (18) Tank passage (BB) Supply oil (DD) Metered oil (HH) Blocked oil (LL) Return oil (A) Armature (B) Energized coil | |
When the LIFT control lever is in the HOLD position, plungers (3) and (4) are in the same position. The plungers do not push up against actuator (1) in the HOLD position. Pilot pump oil flows through pump passage (17) and the oil is stopped by stems (13) and (14) .
RAISE Position of LIFT Operation
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| Illustration 8 | g00406653 |
LIFT Stem in RAISE Position. Two Lever Bucket Control. (1) Actuator (2) LIFT control shaft (3) Plunger (LOWER) (4) Plunger (LIFT) (5) Retainer (6) Retainer (7) Metering spring (8) Metering spring (9) Centering spring (10) Centering spring (11) Detent spring (12) Detent spring (13) LOWER stem (14) LIFT stem (15) Passage to LOWER end of valve spool (16) Passage to LIFT end of valve spool (17) Pump passage (18) Tank passage (BB) Supply oil (DD) Metered oil (HH) Blocked oil (LL) Return oil (A) Armature (B) Energized coil | |
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| Illustration 9 | g00407180 |
LIFT Stem in RAISE Position. Single Lever Bucket Control. (1) Actuator (2) LIFT control shaft (3) Plunger (LOWER) (4) Plunger (LIFT) (5) Retainer (6) Retainer (7) Metering spring (8) Metering spring (9) Centering spring (10) Centering spring (11) Detent spring (12) Detent spring (13) LOWER stem (14) LIFT stem (15) Passage to LOWER end of valve spool (16) Passage to LIFT end of valve spool (17) Pump passage (18) Tank passage (BB) Supply oil (DD) Metered oil (HH) Blocked oil (LL) Return oil (A) Armature (B) Energized coil | |
When the LIFT control lever is moved into the RAISE position, the control lever moves control shaft (2) and actuator (1). The actuator pushes plunger (4) against the force of metering spring (8) and centering spring (10). LIFT stem (14) moves down with the plunger. The oil flows out of passage (16) to the LIFT end of the valve spool. The pressure of the supply oil on the end of the LIFT valve spool moves the spool into the RAISE position.
The oil from the chamber at the opposite end of the LIFT valve spool flows back through passage (15), past the LOWER stem, and back to the tank.
Oil pressure in passage (16) pushes up against LIFT stem (14) and metering spring (8). An increase in pressure within passage (16) pushes LIFT stem (14) against the force of metering spring (8). LIFT stem (14) is pushed off retainer (6) and the stem is held in a pressure modulating position. The LIFT stem keeps a balance between the pressure in passage (16) and the force of metering spring (8) .
When the LIFT control lever is released, centering spring (10) pushes up on plunger (4). Actuator (1) moves shaft (2) and the lever moves back to the HOLD position. LIFT stem (14) moves up as retainer (6) moves up. The retainer moves up as metering spring (8) expands. The oil in passage (16) can now flow back to the tank. The centering springs on the LIFT valve spool in the lift and tilt control valve move the valve spool back to the HOLD position. The extra oil from the end of the LIFT valve spool returns to the tank.
Note: Both types of bucket controls enable the RAISE function when armature (A) and energized coil (B) are in contact. The RAISE function is disabled when coil (B) is de-energized by the LIFT kickout mechanism. The RAISE function is also disabled when the control lever is manually pulled back to the NEUTRAL position.
LOWER Position of LIFT Operation
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| Illustration 10 | g00407183 |
LOWER Stem in LOWER Position. Two Lever Bucket Control. (1) Actuator (2) LIFT control shaft (3) Plunger (LOWER) (4) Plunger (LIFT) (5) Retainer (6) Retainer (7) Metering spring (8) Metering spring (9) Centering spring (10) Centering spring (11) Detent spring (12) Detent spring (13) LOWER stem (14) LIFT stem (15) Passage to LOWER end of valve spool (16) Passage to LIFT end of valve spool (17) Pump passage (18) Tank passage (BB) Supply oil (DD) Metered oil (HH) Blocked oil (LL) Return oil (A) Armature (B) Energized coil | |
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| Illustration 11 | g00407185 |
LOWER Stem in LOWER Position. Single Lever Bucket Control. (1) Actuator (2) LIFT control shaft (3) Plunger (LOWER) (4) Plunger (LIFT) (5) Retainer (6) Retainer (7) Metering spring (8) Metering spring (9) Centering spring (10) Centering spring (11) Detent spring (12) Detent spring (13) LOWER stem (14) LIFT stem (15) Passage to LOWER end of valve spool (16) Passage to LIFT end of valve spool (17) Pump passage (18) Tank passage (BB) Supply oil (DD) Metered oil (HH) Blocked oil (LL) Return oil (A) Armature (B) Energized coil | |
When the LIFT control lever is moved into the LOWER position, the control lever moves control shaft (2) and actuator (1). The actuator pushes plunger (3) against the force of metering spring (7) and centering spring (9). LOWER stem (13) moves down with the plunger. The oil flows out of passage (15) to the LOWER end of the valve spool. The pressure of the supply oil on the end of the LIFT valve spool moves the spool into the LOWER position.
The oil from the chamber at the opposite end of the LIFT valve spool flows back through passage (16), past the LIFT stem, and back to the tank.
Oil pressure in passage (15) pushes up against LOWER stem (13) and metering spring (7). An increase in pressure within passage (15) pushes LOWER stem (13) against the force of metering spring (7). LOWER stem (13) is pushed off retainer (5) and the stem is held in a pressure modulating position. The LOWER stem keeps a balance between the pressure in passage (15) and the force of metering spring (7) .
When the LIFT control lever is released, centering spring (9) pushes up on plunger (3). Actuator (1) moves shaft (2) and the lever moves back to the HOLD position. LOWER stem (13) moves up as retainer (5) moves up. The retainer moves up as metering spring (7) expands. The oil in passage (15) can now flow back to the tank. The centering springs on the LIFT valve spool in the lift and tilt control valve move the valve spool back to the HOLD position. The extra oil from the end of the LIFT valve spool returns to the tank.
LOWER Position With Engine OFF
When the front of the machine is lifted off the ground, there is pressure in the rod end of the lift cylinders. When the bucket is off the ground, there is pressure in the head end of the lift cylinders. The oil flows from the location with the higher pressure into the lift and tilt pilot control valve. When the LIFT control lever is moved to the LOWER position, either the bucket or the front of the machine lowers to the ground.
The oil returns to the tank and the oil pressure in the lift cylinders is released. If the bucket is off the ground, the weight of the bucket and lift arms cause the bucket to lower. If the front of the machine is off the ground, the weight of the machine causes the front of the machine to lower.
HOLD Position of TILT Operation
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| Illustration 12 | g00406650 |
DUMP and TILT BACK Stems in HOLD Position. Two Lever Bucket Control. (1) Actuator (2) TILT control shaft (3) Plunger (TILT BACK) (4) Plunger (DUMP) (5) Retainer (6) Retainer (7) Metering spring (8) Metering spring (9) Centering spring (10) Centering spring (11) Detent spring (12) Detent spring (13) TILT BACK stem (14) DUMP stem (15) Passage to TILT BACK end of valve spool (16) Passage to DUMP end of valve spool (17) Pump passage (18) Tank passage (BB) Supply oil (DD) Metered oil (HH) Blocked oil (LL) Return oil | |
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| Illustration 13 | g00407142 |
DUMP and TILT BACK Stems in HOLD Position. Single Lever Bucket Control. (1) Actuator (2) TILT control shaft (3) Plunger (TILT BACK) (4) Plunger (DUMP) (5) Retainer (6) Retainer (7) Metering spring (8) Metering spring (9) Centering spring (10) Centering spring (11) Detent spring (12) Detent spring (13) TILT BACK stem (14) DUMP stem (15) Passage to TILT BACK end of valve spool (16) Passage to DUMP end of valve spool (17) Pump passage (18) Tank passage (BB) Supply oil (DD) Metered oil (HH) Blocked oil (LL) Return oil (A) Armature (B) Energized coil | |
When the TILT control lever is in the HOLD position, plungers (3) and (4) are in the same position. The plungers do not push up against actuator (1) in the HOLD position. Pilot pump oil flows through pump passage (17) and the oil is stopped by stems (13) and (14) .
DUMP Position of TILT Operation
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| Illustration 14 | g00406653 |
DUMP Stem in DUMP Position. Two Lever Bucket Control. (1) Actuator (2) TILT control shaft (3) Plunger (TILT BACK) (4) Plunger (DUMP) (5) Retainer (6) Retainer (7) Metering spring (8) Metering spring (9) Centering spring (10) Centering spring (11) Detent spring (12) Detent spring (13) TILT BACK stem (14) DUMP stem (15) Passage to TILT BACK end of valve spool (16) Passage to DUMP end of valve spool (17) Pump passage (18) Tank passage (BB) Supply oil (DD) Metered oil (HH) Blocked oil (LL) Return oil (A) Armature (B) Energized coil | |
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| Illustration 15 | g00407180 |
DUMP Stem in DUMP Position. Single Lever Bucket Control. (1) Actuator (2) TILT control shaft (3) Plunger (TILT BACK) (4) Plunger (DUMP) (5) Retainer (6) Retainer (7) Metering spring (8) Metering spring (9) Centering spring (10) Centering spring (11) Detent spring (12) Detent spring (13) TILT BACK stem (14) DUMP stem (15) Passage to TILT BACK end of valve spool (16) Passage to DUMP end of valve spool (17) Pump passage (18) Tank passage (BB) Supply oil (DD) Metered oil (HH) Blocked oil (LL) Return oil (A) Armature (B) Energized coil | |
When the TILT control lever is moved into the DUMP position, the control lever moves control shaft (2) and actuator (1). The actuator pushes plunger (4) against the force of metering spring (8) and centering spring (10). DUMP stem (14) moves down with the plunger. The oil flows out of passage (16) to the DUMP end of the valve spool. The pressure of the supply oil on the end of the TILT valve spool moves the spool into the DUMP position.
The oil from the chamber at the opposite end of the TILT valve spool flows back through passage (15), past the TILT BACK stem, and back to the tank.
TILT BACK Position of TILT Operation
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| Illustration 16 | g00407183 |
TILT BACK Stem in TILT BACK Position. Two Lever Bucket Control. (1) Actuator (2) TILT control shaft (3) Plunger (TILT BACK) (4) Plunger (DUMP) (5) Retainer (6) Retainer (7) Metering spring (8) Metering spring (9) Centering spring (10) Centering spring (11) Detent spring (12) Detent spring (13) TILT BACK stem (14) DUMP stem (15) Passage to TILT BACK end of valve spool (16) Passage to DUMP end of valve spool (17) Pump passage (18) Tank passage (BB) Supply oil (DD) Metered oil (HH) Blocked oil (LL) Return oil (A) Armature (B) Energized coil | |
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| Illustration 17 | g00407185 |
TILT BACK Stem in TILT BACK Position. Single Lever Bucket Control. (1) Actuator (2) TILT control shaft (3) Plunger (TILT BACK) (4) Plunger (DUMP) (5) Retainer (6) Retainer (7) Metering spring (8) Metering spring (9) Centering spring (10) Centering spring (11) Detent spring (12) Detent spring (13) TILT BACK stem (14) DUMP stem (15) Passage to TILT BACK end of valve spool (16) Passage to DUMP end of valve spool (17) Pump passage (18) Tank passage (BB) Supply oil (DD) Metered oil (HH) Blocked oil (LL) Return oil (A) Armature (B) Energized coil | |
When the TILT control lever is moved into the TILT BACK position, the control lever moves control shaft (2) and actuator (1). The actuator pushes plunger (3) against the force of metering spring (7) and centering spring (9). TILT BACK stem (13) moves down with the plunger. The oil flows out of passage (15) to the TILT BACK end of the valve spool. The pressure of the supply oil on the end of the TILT valve spool moves the spool into the TILT BACK position.
The oil from the chamber at the opposite end of the TILT valve spool flows back through passage (16), past the DUMP stem, and back to the tank.