2Pump Main Body Assembly and Disassembly Procedures

2 Pump Main Body Assembly and Disassembly Procedures

1-1Tools

The table below shows the tools required for the assembly and disassembly of the K7V pump. The bolts and plugs may vary by pump type.

Tool name and dimensions Required tools are indicated with Hydraulic pump type

Name B K7V63

Hexagon socket head bolt Part name

Buried plug (PT screw) ROH plug VP plug (PF screw)

Hexagon socket head stop screw

Hexagon bar wrench 2 - - - M4 2.5 - - - M5 3 - - - M6 4 M5 Rc 1/16 - M8 5 M6 Rc 1/8 - M10 6 M8 Rc 1/4 G 1/4 M12, M14 8 M10 Rc 3/8 G 3/8 M16, M18 10 M12 Rc 1/2 G 1/2 M20 14 M16, M18 Rc 3/4 G 3/4 17 M20, M22 Rc 1 G 1 19 M24, M27 - - 21 - - - 22 M30 - - -

Closed wrench Socket wrench Double-head (single-head) wrench

19 M12 - G 1/4 22 - - G 3/8 24 M16 - - 27 M18 - G 1/2 30 M20 - - 36 - - G 3/4 41 - - G 1 50 - - G 11/4 55 - - G 11/2 Monkey wrench - Medium-sized × 1 Screwdriver - Medium-sized flathead screwdriver × 2 Hammer - Plastic hammer × 1 Pliers - TSR-160 for stop ring Steel rod - Diameter φ4 or less L = 100 Torque wrench - With adjustable specified torque tightening

1-2Disassembly procedure

Read the entire section below on the disassembly procedure, and follow the procedure for disassembling the pump. The numbers in parentheses on the rear of each part correspond to the part numbers in Figure 1. Pump parts breakdown. 1. Select the location for disassembling the regulator.

Precautions (1)Find a clean location to disassemble the regulator.

Place a rubber plate or cloth on the work table so as not to damage the parts.

2. Use cleaning oil to remove any dirt or rust from the surface of the pump.

3. Remove the oil drain port plug (468) and drain the oil from the pump casing (271).

Precautions (1)Remove plugs from both front and rear pumps.

4. Remove hexagon socket head bolts (412 and 413), and remove the regulator.

Precautions (1)See the Regulator Assembly and

Disassembly Procedures for how to disassemble the regulator.

5. Face down the pump regulator installation surface horizontally on the work table, remove the flange socket (435) and remove the PTO unit (05).

Precautions (1)When facing down the regulator installation surface, be sure to place a rubber plate or similar material on the work table so as not to damage the regulator installation surface. (2)Refer to the Explanation of PTO Unit

Manual for how to disassemble the PTO unit.

6. Loosen the flange socket (435), and remove the gear pump (04).

7. Loosen hexagon socket head bolts (401 and 402) that fasten together the pump casing (F) (271), the pump casing (R) (272) and the valve block (312).

8. Separate the pump casing (F) (271), pump casing (R) (272) and valve lock (312).

Precautions (1)When separating the pump casing and valve block, remove the 1st gear (116) at the same time.

9. Remove the cylinder block (141) straight out from the pump casing (F) (271) toward drive shafts (111 and 113), and remove piston subassemblies (151 and 152), the holder plate (153), the spherical bush (156), and cylinder spring (157) at the same time.

Precautions (1)Be careful not to damage the sliding surfaces of the cylinder block, spherical bush, shoes, and swash plate.

10.Remove hexagon socket head bolts (406), and remove the seal cover (F) (261).

Precautions (1)The seal cover (F) can be easily removed by inserting a flathead screwdriver into the notch on the seal cover (F) and pulling it out. (2)The seal cover (F) has an oil seal, so be careful not to damage the oil seal when removing the seal cover (F).

11.Tap the rear of drive shafts (111 and 113), and separate it from pump casings (271 and 272).

12.Remove the shoe plate (211) and swash plate (212) from pump casings (271 and 272).

13.Insert a wire to the unlocking hole (see figure below) on the swash plate support board (251). While pressing the rotation lock pin (255), turn the swash plate support counterclockwise to remove it out of the pump casing.

Precautions (1)When holding the lock pin with the wire, be careful not to mistake the small hole (oil path) on the circular arc of the swash plate for the unlocking hole. (2)When removing the swash plate support, rotation lock pin and the set spring may spring out, for which care should be taken.

14.Remove valve plates (313 and 314) from the valve block (312).

Precautions (1)This plate may be removed also in step 7.

15.If necessary, remove the Qmin plug (533), the stopper (L) (534), stopper (S) (535), the servo piston (532), and tilting pin (531) from pump casings (271 and 272), and remove the needle bearing (124) from the valve block (312).

Precautions (1)To avoid damaging the head of the tilting pin, use a jig when removing the tilting pin. (2)The section where the tilting pin and servo piston are bonded is coated with Locktite, so be careful not to damage the servo piston. (3)Do not remove the needle bearing unless it is at the end of its service life. (4)Do not loosen the hexagon nut of the valve block and Qmin plug or flow setting may change.

1-3Assembly procedure

The assembly procedure is the reverse of the disassembly procedure. However, follow the precautions below. (1)Be sure to repair any parts damaged during disassembly, and prepare replacement parts in advance. (2)Thoroughly clean all parts with cleaning oil and air blow before assembling. (3)Be sure to coat sliding parts and bearings with clean hydraulic oil before assembling. (4)As a rule, replace all O-rings, oil seals, and other seal parts with new parts. (5)Use a torque wrench to tighten all installation bolts and plugs to the torque specified in the maintenance standards. (6)Be careful not to mix up the pump parts for the front and rear of the tandem pump.

1. Install the set spring (256) and rotation lock pin (255) to the pump casing (271). Align the swash plate support board (251) to the spigot portion of pump casing, turn it clockwise and anchor the swash plate support board with the rotation lock pin.

Precautions (1)If the servo piston, tilting pin, stopper (L), stopper (S) and Qmin plug have been removed, assemble these parts in the pump casing in advance. (2)To avoid damaging the tilting pin head and feedback pin, use a jig when tightening the servo piston and tilting pin.

Also apply Locktite (medium adhesive strength) to the threaded portions.

2. Install the shoe plate (211) to the swash plate (212). Insert the tilting bushing of swash plate to the tilting pin (531) and install the swash plate and shoe plate correctly to the swash plate support board (251).

Precautions (1)Use the tips of both fingers to check that swash plate moves smoothly. (2)Coat the swash plate, swash plate support board, and all sliding sections with grease for easier installation of the drive shaft. (3)Be careful not to damage the sliding surface of the shoe plate.

3. Install drive shafts (111 and 113) being attached with the cylinder roller bearing (123), bearing spacer (127), and stop ring (824) to pump casings (271 and 272).

4. Attach the seal cover (F) (261) to the pump casing (271), and secure with hexagon socket head bolts (406).

Precautions (1)Lightly coat the oil seal of the seal cover (F) with grease. (2)Attach the oil seal while being careful not to damage it.

5. Assemble the piston cylinder subassembly [the cylinder (141), piston subassemblies (151 and 152), holder plate (153), spherical bush (156), and cylinder spring (157)], and insert it into the pump casing in alignment with the phase of the spherical bush and cylinder spline.

6. Install into the valve plate (313) while aligning valve blocks (313 and 314) with the spring pin (886).

Precautions (1)Be careful not to mistake the intake and discharge directions of the valve plate.

7. Face down the pump regulator installation surface horizontally on the work table, and install pump casings (271 and 272) and the valve block (312).

Precautions (1)When facing down the regulator installation surface, be sure to place a rubber plate or similar material on the work table so as not to damage the regulator installation surface. (2)Be careful not to mistake the valve block direction. (Install the valve block with the regulator facing up and the suction flange facing to the right when viewing the valve block from the front.) (3)When installing the pump casing and valve block, install the 1st gear at the same time.

8. Tighten the valve block (312) and pump casings (271 and 272) with hexagon socket head bolts (401 and 402).

9. Tighten the flange socket (435) and install the gear pump (04). Tighten the valve block (312) and pump casings (271 and 272) with hexagon socket head bolts (401).

10.Tighten the flange socket (435) to the valve block (312) and install the PTO unit (05).

Precautions (1)Attention must be paid to the installation direction of PTO unit.

For a pump having no PTO unit, install the cover (326) using hexagon socket head bolts (414).

11.Insert the feedback pin of the tilting pin into the feedback lever of the regulator, install the regulator, and tighten hexagon socket head bolts (412 and 413).

Precautions (1)Install the regulator, making sure not to mistake the front and the rear of the regulator.

12.Attach the drain port plug (467) to finish assembly.

Figure 1. Pump parts breakdown

Breakdown diagram

Note: (W) (X) (Y) (Z) and (K) (L) (M) (N) in this diagram shows the installation locations of regulator. “See regulator breakdown diagrams (drawing Nos. 21290-1821 and 21290-1822)”

2. Maintenance Standards for Pump Main Unit 2-1Standards for replacing worn parts

If any part exceeds the standard values below and is worn, replace or readjust that part. If, however, the appearance of the part shows significant damage, replace that part.

Part name and inspection item

Standard dimensions/ recommended replacement value Hydraulic pump type K7V63 Solution

Piston to cylinder bore clearance (D-d) 0.032/0.056 Replace piston or cylinder

Piston, shoes and caulking section backlash (δ) 0 - 0.1/0.3 Replace piston and shoe assembly Shoe thickness (t) 3.9/3.7 Replace piston and shoe assembly Free height of cylinder spring (L) 41.1/40.3 Replace cylinder spring Assembled height of holder plate and spherical bush (H-h) 17.0/15.7 Replace holder plate or spherical bush

Piston to cylinder bore clearance (D-d) Free height of cylinder spring (L)

Piston, shoes, and caulking section backlash (δ) Shoe thickness (t) Assembled height of holder plate and spherical bush (H-h)

2-2Standards for replacing the cylinder, valve plate, and swash plate (shoe plate)

2-3Tightening torque

Valve plate (sliding section) Swash plate (shoe plate section) Cylinder (sliding section) Surface roughness requiring repair Standard surface roughness (repair value) 3-Z

0.4Z or lower (lapping)

Part name Size Tightening torque (N•m) Tool name (mm) M5 6.9 B = 4

Hexagon socket head bolt (material SCM435)

PT plug

(material S45C) Note) Wrap the seal tape 1.5 2 times.

ROH plug material G3/8 or below: S45C G1/2 or above: SCM435 [ ]

M6 12 5 M8 29 6 M10 57 8 M12 98 10 M14 160 12 M16 240 14 M18 330 14 M20 430 17 Rc1/16 6.9 4 Rc1/8 10 5 Rc1/4 17 6 Rc3/8 34 8 Rc1/2 49 10 G1/4 29 6 G3/8 74 8 G1/2 98 10 G3/4 150 12 Hexagon bar wrench

Same as above

Same as above

Figure 2. Pump dimensional outline diagram

Fig. 3 Pump assembly cross-section diagram