Procedures for Assembly and Disassembly of Travel Remote Control Valve

When disassembling the valve, read the disassembly procedures thoroughly before following the sequence below. The numbers in the parentheses after the part names indicate codes in "Attached diagram 1. Remote control valve assembly cross-section diagram" on page244. 1.Maintenance procedures (1) Disassembly procedures [1] Preparations 1) Prepare a sufficiently spacious, solid and stable work platform so that parts will not fall or move during work. 2) Prepare tools and materials. [2] General work precautions 1) Each part has been manufactured with a high degree of precision, so be careful not to let parts bump each other or fall when handling them. 2) If parts are struck or pulled with excessive force during work because they are tight, this may cause burrs or damage which may then cause reductions in performance or oil leak due to faulty assembly. Perform work carefully and thoroughly. 3) Rust may form on parts due to moisture or debris if the valve is left disassembled or if work is abandoned in the middle of disassembly. If work must be halted, be careful about preventing rust from forming and dust settling on parts. [3] Disassembly procedure 1) Clean the remote control valve with white kerosene. •Place plugs in each port. 2) Use shock plate to secure the remote control valve in a vise. Remove the bellows (501) from the covers (201) and remove the bellows by pulling upwards.

3) Use a hexagon wrench on the hexagon socket head locking screws (423) to loosen them.

Be careful, as application of Loctite #241 makes the loosening torque high.

4) Place a round rod (φ8 mm or less) against one end of the cam shafts (413) and lightly strike it with a hammer to remove the shafts.

5) Remove the cams (420) as an assembly with the locking screws (471) and lock nuts (472) left attached.

Record the positions of the cams in relation to the covers (201).

Be careful when removing, as the push rods (214) may fly off.

6) Use a hexagon wrench on the hexagon socket head bolts (271) to loosen and remove them.

7) Remove the covers (201).

Record the positions of the covers in relation to the casing (101).

Be careful when removing, as the push rods (214) or plugs (202) may fly off due to the damping springs (336) and (337). (The plugs are only kept in the casing by the sliding resistance of the O-rings (212).)

8) Remove push rods (214) from the plugs (202).

Record the positions of the plugs in relation to the push rods.

Be careful not to scratch the surface of the push rods.

Be careful when removing, as plugs may fly off.

9) Remove the plugs (202) with the grease caps (203) and NHU packings (210) left attached.

Record the positions of the plugs in relation to the casing holes.

Be careful when removing, as the pistons (224) may fly off due to the damping springs (336) and (337).

10)Remove the pistons (224).

Record the positions of the pistons in relation to the casing holes.

11)Remove the damping springs (336) and (337) from the casing (101).

Record the positions of the damping springs in relation to the casing holes.

12)Remove the spring seatings (218) from the casing (101).

Record the position of the spring seatings in relation to the casing holes.

13)Use a magnet, etc. to remove steel balls (225).

Be careful not to lose steel balls.

14)Use a hexagon wrench to remove the hexagon socket head bolts (220).

15)Remove the damper casing (102) and remove the O-rings (211) and (213) from the casing. •Record the position of the damper casing in relation to the casing (101). •Be careful when removing, as the pressure reducing valve assembly may fly off due to the return springs (335).

16)Remove the pressure reducing valve assemblies and return springs (335) from the casing (101).

Record the positions of these parts in relation to the casing holes.

17)Lay the covers (201) on their sides on a level surface, place the special tool 1 against the bushings (412), and remove the bushings by lightly striking them with a hammer.

18)Secure each cam assembly in a vise, use a wrench to loosen the lock nuts (472), and remove the lock nuts and locking screws (471).

As neutral adjustment of locking screws is necessary during assembly, handle them as part of the cam assembly as long as replacement of locking screws is not necessary.

19)For disassembly of the pressure reducing valve assemblies, place the bottom end of the spools (301) perpendicular on a level work platform, lower the spring seatings (311), and use the end of a small flathead screwdriver to remove the 2 halfcircle washers 1 (215).

Be careful not to scratch the surface of the spools.

Do not insert the spring seatings more than 4 mm. 20)Separate the spools (301), spring seatings (311), secondary pressure springs (324), washers 2 (217), and washers 3 (313).

Handle as an assembly until assembly is performed.

Washers 2 are used for pre-set adjustment of the secondary pressure springs, so thickness is different for each spool assembly. Additionally, these are sometimes not used, so record the status for each assembly. 21)Remove the grease cups (203) from the plugs (202).

22)Remove the NHU packings (210) from the plugs (202). Use a small flathead screwdriver, etc. to remove.

Be careful not to scratch the inner surface of the plugs.

23)Remove the O-rings (212) from the plugs (202).

24)Cleaning parts •Clean each part by placing it in a rough cleaning container filled with white kerosene. (Rough cleaning) 25)Scratching can easily occur if cleaning of parts is begun just after parts are immersed in white kerosene, so let each part sit in white kerosene until debris and grease sufficiently loosen off from the surface of parts and float to the surface.

If the white kerosene is dirty, this will encourage damage to parts and result in reduced performance after reassembly. Thoroughly manage the level of cleanliness of the white kerosene. •Clean each part by placing it in a finish cleaning container filled with white kerosene, and thoroughly clean each part, including the interior, while slowly rotating it (finish cleaning).

Use a rag to thoroughly remove white kerosene adhered to parts. 26)Do not dry parts with compressed air, as this will damage parts and cause rust to form due to debris and moisture being dispersed into the atmosphere. 27)Preventing rust on parts

Apply an anti-rust agent to each part.

Rust will form on parts if they are left as is after cleaning, and this will cause reduced performance of functions after reassembly.

(2) Assembly procedures [1] Preparations 1) As with disassembly, prepare a work platform, tools and materials. [2] General work precautions 1) Observe the same general work precautions as with disassembly. 2) When performing assembly, remove metal fragments and foreign matter from all parts, and check that there are no burrs or nicks on parts. If there are burrs or nicks, use a whetstone to remove them. 3) As a rule, replace all O-rings and NHU packings. 4) When installing O-rings and NHU packings, be careful not to damage them. (Apply a thin layer of grease to ensure smooth installation.) 5) When installing parts, using grease is good for preventing parts from falling. 6) Tighten bolts, etc. to the torque values indicated in the assembly cross-section diagram. 7) After assembly is complete, place plugs in all of the ports to prevent entry of debris. [3] Assembly procedures 1) Install the washers 3 (313), washers 2 (217), secondary pressure springs (324), and the spring seatings (311) onto each of spools (301) in that order. Washers 2 are used for pre-set adjustment of the secondary pressure springs, so thickness is different for each spool assembly. Additionally, these are sometimes not used. Check the status recorded during disassembly and attach parts accordingly. 2) Place the bottom end of the spools (301) perpendicular on a level work platform, push the spring seatings (311) down, and install the 2 half-circle washers 1 (215) onto the spring seatings in such a way that they are not on top of each other. Install the washers 1 so that the sharp edge side faces up and the washer catches the head of the spool. Do not insert the spring seatings more than 4 mm.

3) Install the return springs (335) in the casing (101).

Install them in the positions they were in before disassembly.

4) Install the pressure reducing valve subassemblies assembled in the previous steps 1) and 2) into the casing (101).

Install them in the positions they were in before disassembly.

When installing the pressure reducing valve subassemblies, be careful not to strongly strike the casing corners with the bottom ends of the spools.

5) Install O-rings (211) and (213) on the casing.

6) Tighten the damper casing (102) and casing (101) with the hexagon socket head bolts (220) to the specified torque.

Tightening torque: 8.8 ± 1 N•m •Install them in the positions they were in before disassembly. •Tighten the 2 hexagon socket head bolts (220) evenly, and tighten the damper casing (102) in a parallel orientation.

7) Install the steel balls (225) into the bushings (412).

8) Install the spring seatings (218) into the bushings (412).

Install them in the positions they were in before disassembly.

9) Install the damping springs (336) in the casing (101).

Install them in the positions they were in before disassembly.

10)Install the damping springs (337) in the casing (101).

Install them in the positions they were in before disassembly.

Be careful that they do not become entangled with damping springs (336).

11)Install the pistons (224).

Install them in the positions they were in before disassembly.

12)Install O-rings (212) on the plugs (211).

13)Install NHU packings (210) into the plugs (202).

When installing the NHU packings, be careful of the installation direction. (See the diagram.)

Before installing NHU packings, apply a thin layer of grease.

14)Install grease cups (203) into the plugs (202).

15)Install push rods (214) into the plugs (202).

Before installing push rods, apply hydraulic oil to the rod surfaces.

Do not press the rods in strongly, as this may damage the NHU packing lip sections.

NHU packing

16)Install the push rod subassemblies assembled in the previous steps 12), 13), 14), and 15) into the casing (101).

17)Use special tool 1 on the covers (201) to press down the bushings (412), and lightly strike the bushings with a hammer to press fit them.

Be careful that the ends of the bushings do not stick out from within the cover.

18)Install the covers (201) on the casing (101).

Install them in the positions they were in before disassembly.

Be careful of the cover rising up due to the damping springs (336) and (337).

19)Tighten the hexagon socket head bolts (271) to the specified torque.

Tightening torque: 55 ± 9.8 N•m

Be careful that the covers are horizontal.

20)Temporarily install the locking screws (471) and lock nuts (472) on the cams (420).

21)Install the cams (420) on the covers (201).

Install them in the positions they were in before disassembly.

22)While holding the cams (420), insert the cam shafts (413) from the outside.

23)Apply Loctite #241 or the equivalent to the surfaces of the hexagon socket head locking screws (423).

24)Tighten the hexagon socket head locking screws (423) to the specified torque.

Tightening torque: 6.9 ± 1 N•m

25)Adjust the height of the locking screws (471) so that the top surface of the cams (420) and the bottom surface of the covers (201) are parallel, and tighten the lock nuts (472) to the specified torque after rotating the cams left and right to check if there is any neutral backlash.

Tightening torque: 33.3 ± 3.4 N•m

Even if the push rods (214) are pressed in too much by the locking screws, backlash during neutral will occur. Use caution as this may cause the sudden movement when starting the engine. 26)Tilt the cams (420) and fill the grease cups (203) of the plugs (202) with grease while filling grease to the top of the push rods (214).

For grease application and filling, use a flat object made of soft material so as to not scratch the push rod or plug surfaces.

27)After mounting the top end of the bellows (501) on the cams (420), mount the bottom end into the grooves on the covers (201).

Before mounting the bottom end of the bellows into the grooves of the covers, spray anti-rust oil on the parts within the bellows.

Be careful that the bellows are properly mounted in the grooves and not twisted, as this may reduce anti-rust and antimoisture protection.

2.Causes of trouble and countermeasures

It is not always easy to find where the source of trouble is located. A few problems that may sometimes occur are listed in the table below. Repair of these problems can be difficult, so see the suggested causes and solutions in the table for assistance.

The table below shows general symptoms, suggested causes and also solutions. However, the cause of machine problems are often not rooted in just a single part. Problems are often due to the relationship of one part with another. Also keep in mind that solutions other than those listed in the table may sometimes be necessary.

The table below does not include all possible causes and countermeasures. Accordingly, further investigation of problems and causes should be done by an experienced and qualified repair person, as necessary.

Symptom Secondary pressure is not rising.

Secondary pressure is unstable. Cause

1. Insufficient primary pressure 2. Secondary pressure spring (324) is worn. 3. The gap between spool and the casing is abnormally large. 4. There is backlash in the operation section.

1. Sliding parts are sticking. 2. Tank line pressure is variable. 3. Air is getting into lines.

Secondary pressure is high.

Damping is not working. 1. Tank line pressure is high. 2. Sliding parts are sticking. 1. Air is gathering in the piston chamber.

2. Sliding parts are sticking. 3. Damping spring (336) and/or (337) are worn. 4. The gap between piston (224) and the casing is abnormally large. 5. There are check valve operation problems. 6. The piston metering hole is abnormally large. Damping torque is high. 1. Sliding parts are sticking. 2. Piston metering hole is clogged. Solution

1. Maintain primary pressure. 2. Replace it with new part.

3. Replace spool and casing assembly.

4. Disassemble and assemble or replace operation section parts. 1. Repair the sticking sections. 2. Return directly to the oil tank. 3. Perform operation several times and let out air.

1. Return directly to the oil tank. 2. Repair the sticking sections. 1. Perform operation several times and let out air. 2. Repair the sticking sections. 3. Replace it with new part.

4. Replace piston and casing assembly.

5. Disassemble and adjust the check valve section. 6. Replace piston.

1. Repair the sticking sections. 2. Repair or replace piston.

Tightening torque list Code Screw size Tightening torque 220 M6 8.8 ± 1 N•m 271 M12 55 ± 9.8 N•m 423 M6 6.9 ± 1 N•m (Loctite coating) 472 M10 33.3 ± 3.4 N•m

Note The hydraulic parts are important safety mechanisms, so performance and function cannot be guaranteed if they are disassembled and reassembled. Attached diagram 1. Remote control valve assembly cross-section diagram

Code Part name Q'ty Code Part name Q'ty Code 101 Casing 1 217 Washer 2 102 Casing (damper) 1 218 Spring seating 4 336 Spring 4 337 Spring

201 Cover 2 220 Hexagon socket head bolt 2 412 Bushing

202 Plug 4 224 Piston 2D085 4 413 Camshaft

203 Grease cup 4 225 Steel ball 2 420 Cam Part name Q'ty 4 4 4 2 2

210 NHU packing 211 O-ring 212 O-ring 213 O-ring 214 Push rod 245 Washer 1 4 271 Hexagon socket head bolt 2 423 Hexagon socket head locking screw 2 2 301 Spool 4 471 Locking screw 4

4 311 Spring seating 4 472 Lock nut 4

4 313 Washer 3 4 501 Bellows 2

4 324 Spring 8 335 Spring 4 4

[1] Special jig 1 (for bushing removal)