- Excavator:
- 308D CR (S/N: FYC1-UP; GBT1-UP)
Introduction
This Special Instruction contains information for reworking 308DCR travel control valve and travel motor.
Required Parts
The following table contains the necessary parts for the rework procedure.
| Materials | ||||
|---|---|---|---|---|
| Category | QTY | New Part No | Description | Former Part No |
| Control Valve | 2 | 356-6924 | Plunger As | 324-7800 |
| Final Drive | 2 | 366-9834 | Spool | 326-8955 |
| 2 | 366-9835 | Spring | 306-7929 | |
| 2 | 114-8229 | Plug-Orifice | 326-8956 | |
| Lines Gp-Pilot | 1 | 6v-8647 | Adapter-STR | 268-1601 |
| 1 | 3J-7354 | Seal-O-Ring | ||
| 1 | 4J-5477 | Seal-O-Ring | ||
Rework Procedure
| NOTICE |
|---|
Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting, and repair of the product. Be prepared to collect fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Cat Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Cat products. Dispose of all fluids according to local regulations and mandates. |
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Hydraulic oil pressure can remain in the hydraulic systems after the engine and pump have been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic systems. To prevent possible injury, refer to the section, Testing and Adjusting, "Hydraulic System Pressure - Release" before any fitting, hose or component is loosened, tightened, removed or adjusted. When possible, the bucket or attachment must always be lowered to the ground before service is started. When it is necessary for the boom to be in the raised position while tests or adjustments are done, be sure that the boom, stick and bucket or attachment have correct support. The swing lock (if equipped) must be engaged before service is started. Always move the machine to a location away from the travel of other machines. Be sure that other personnel are not near the machine when the engine is running and tests or adjustments are being made. |
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Preparation for Rework
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Be sure all personnel are clear of the equipment while the equipment is being lowered. Failure to stay clear of the equipment while the equipment is being lowered may result in personal injury. |
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Set vacuum pressure on hydraulic tank fill port using pressurized air to minimize oil leak.
Note: Do not use gloves to prevent contaminants from entering the hydraulic system.
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Personal injury can result from hydraulic oil pressure and hot oil. Hydraulic oil pressure can remain in the hydraulic system after the engine has been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic system. Make sure all of the work tools have been lowered to the ground, and the oil is cool before removing any components or lines. Remove the oil filler cap only when the engine is stopped, and the filler cap is cool enough to touch with your bare hand. |
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Accidental machine starting can cause injury or death to personnel working on the machine. To avoid accidental machine starting, turn the battery disconnect switch to the OFF position and remove the key. If the machine is not equipped with a battery disconnect switch, disconnect the battery cables from the battery and tape the battery clamps. Place a do not operate tag at the battery disconnect switch location to inform personnel that the machine is being worked on. |
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| Illustration 1 | g02476172 |
308D Control Valve location | |
Change the Travel Spools
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| Illustration 2 | g02476202 |
Valve body showing typical location of Spool. | |
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| Illustration 3 | g02476203 |
Exploded view of Spool . (A) O-Ring seal (B) Spool (C) Cap (D) Bolts | |
- Disassemble Spool caps at sections to change Spools. Begin by removing the two Hex/Socket head 5mm bolts that retain the Spool caps. Mark the caps and Pilot hoses to identify the pair.
- While pulling out the Spool, slowly rotate and pull out the Spool from the Valve body.
Note: Care should be taken to avoid scratching the surface of the Valve body when removing the Spool.
- Insert the new part number. Refer to Table 1.
Note: Be sure to clean the new Spool prior to reassembly.
- Push the new Spool into the Valve body while slowly rotating the Spool.
- Replace the Cap.
Note: Remember to check the alignment of the O-Ring while setting the Cap back into position on the Valve body.
- Complete the procedure by securing the Cap with the two Hex/Socket Head 5mm bolts and tighten the bolts to the torque spec of 13 N·m (9.6 lb ft)
Change the Spool and Spring of the Final Drive
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| Illustration 4 | g02476270 |
Example of Final Drive | |
- Remove Plug that retains the Spool and Spring from the Final Drive by using a 8mm hex head socket.
- After removing the plug, pull out the Spool and Spring.
- Remove the Spool and Spring by slowly pulling, while rotating the Spool.
Note: Care should be taken to avoid scratching the walls of the Valve Body during this process.
- Insert the new Spool and Spring. Refer to Table 1 for the correct part number.
Note: Be sure to clean the Spool and Spring prior to reassembling into the Valve Body.
- Carefully push the new parts into the Final Drive body by slowly rotating the Spool and Spring back into position.
- Replace the Plug back into the Final Drive.
- Tighten the plug securely to a torque spec of 78.5 N·m (57.9 lb ft)
Change the Orifice of the Final Drive
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| Illustration 5 | g02476304 |
Typical location of Orifice on Final Drive (A) Old Orifice is 0.05 mm (0.00197 inch) Diameter (B) New Orifice is 0.8 mm (0.03 inch) Diameter | |
- Remove hoses from Final Drive.
Note: Be sure to move hoses aside as not to interfere with the rest of this procedure.
- Remove the Plug that retains the Orifice from the Final Drive. To access the Orifice, remove the Plug by using a 5mm hex head socket.
- Remove the Orifice using a 4mm hex head socket.
Note: Care should be taken not to damage the socket during removal of the Orifice.
- Reinstall and tighten the new Orifice. Refer to Table 1 for correct part number.
Note: Remember to clean the new Orifice prior to assembly.
- Tighten the Orifice to a torque spec of 9.81 mm ±1.0 N·m (0.390 inch.±.74 lb ft).
- Reinstall the Plug into the Final Drive using the 5mm hex head socket.
- Tighten the plug to the torque spec of 19.6 N·m ± 2.0 N·m (14.45618 lb ft ± 1.48 lb ft).
Change the Connector of Lines Gp-Pilot C
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| Illustration 6 | g02476351 |
Change the Connector (A) Old connector 268-1601 Orifice Connector As . (B) New connector 148-8316 Connector As . | |
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| Illustration 7 | g02476362 |
Connector location Port P1 | |
Change the Connector with Orifice from 268-1601 Orifice Connector As to Connector 148-8316 Connector As .
Note: The Orifice size of the old Connector is 0.07 mm (0.00276 inch) Diameter. The new Connector is without Orifice.
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| Illustration 8 | g02476366 |
308DCR FB 307-2757 Main Control Valve Gp with Medium Pressure | |
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| Illustration 9 | g02476367 |
308DCR FB 307-2753 Main Control Valve Gp | |
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| Illustration 10 | g02476368 |
308DCR SB 307-2755 Main Control Valve Gp | |
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| Illustration 11 | g02476371 |
308DCR SB 307-2759 Main Control Valve Gp with Medium Pressure | |