Troubleshooting (Continued)
| Problem |
| Cause | Correction |
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| Unable to push valve |
| Paint on valve spool; sticking | Clean valve spool. Binding is usually | |||||
| spool in |
| valve spool or scored valve | caused from an overtightened plug, | |||||
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| spool | mounting bolt, fitting in valve body or | |||||
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| tie rod bolt. If a plug or fitting in the valve | |||
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| body is leaking, do not overtighten in an | |||
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| effort to stop leak. This will distort body | |||
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| casting and cause spools to bind. Instead, | |||
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| the plug and fitting should be removed | |||
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| from valve body and be reconnected, | |||
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| using a new | |||
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| excessive pressure on mounting bolts. | |||
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| The rods should be torqued to 30 ft. lbs. | |||
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| Never force spool. |
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| Oil leakage past spool seal into | Remove cap. If it contains oil replace spool | |||||
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| spool cap | seal | |||||
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| sure it is flat. If it has been “belled” check | |||
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| for restriction from outlet to reservoir of | |||
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| valve which would cause excessive back | |||
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| pressure. If supply and return lines are | |||
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| reversed, pressure on low pressure / return | |||
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| side of valve will cause problem. | |||
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| Make sure hoses are connected correctly | |||
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| at bulkhead connection on backhoe. |
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| Bent spool | Replace with new spool section. | |||||
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| Foreign particles | Clean system and valve. | |||||
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| Misalignment of control handle | Check linkage for binding condition. | |||||
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| linkage |
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| Spring centered spools |
| Paint on valve spool; sticking | Clean valve spool. Binding is usually | |||||
| do not return to neutral |
| valve spool or scored valve | caused from an over tightened plug, | |||||
|
|
| spool | mounting bolt, fitting in valve body or | |||||
|
|
|
|
|
| tie rod bolt. If a plug or fitting in the | |||
|
|
|
|
|
| valve body is leaking, do not overtighten | |||
|
|
|
|
|
| in an effort to stop leak. This will distort | |||
|
|
|
|
|
| body casting and cause spools to bind. | |||
|
|
|
|
|
| Instead, the plug and fitting should be | |||
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|
|
|
|
| removed from valve body and be | |||
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|
|
|
|
| reconnected, using a new | |||
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|
|
| not apply excessive pressure on | |||
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|
|
|
| mounting bolts. The rods should be | |||
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|
|
|
|
| torqued to 30 ft. lbs. Never force spool. |
| ||
|
|
| Oil leakage past spool seal into | Remove cap. If it contains oil replace spool | |||||
|
|
| spool cap | seal | |||||
|
|
|
|
|
| sure it is flat. If it has been “belled” check | |||
|
|
|
|
|
| for restriction from outlet to reservoir of | |||
|
|
|
|
|
| valve which would cause excessive back | |||
|
|
|
|
|
| pressure. If supply and return lines are | |||
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|
|
|
|
| reversed, pressure on low pressure / return | |||
|
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|
|
|
| side of valve will cause problem. | |||
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| Make sure hoses are connected correctly | |||
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| at bulkhead connection on backhoe. |
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| Broken return springs | Replace springs. |
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| Bent spool | Replace with new spool section. | |||||
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| Foreign particles | Clean system and valve. |
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| Misalignment of control handle | Check linkage for binding condition. | |||||
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| linkage |
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