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Precautions when changing a hydraulic valve

Reviewed by Julie Gunn, Head of Services, SALUS Safety

The question, as asked: When changing a hydraulic valve what are some precautions I should take to?

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Rosie's answer

Published by SALUS

When replacing or maintaining hydraulic valves, keep the following points in mind:

1\. Ensure you have proper personal protection at all times because escaping fluid from a hydraulic pressure leak can damage your eyes, penetrate the skin and cause serious injury. [2]

2\. Take precautions to assure the absolute cleanliness of the hydraulic oil, as even small amounts of dirt or foreign materials in the system can cause wear or damage to components, as well as general faulty operation of the hydraulic system. [2]

3\. If there is a hydraulic system failure, drain and flush the entire system and replace the filter cartridges. A complete oil change must be made under these circumstances. [2]

4\. Check the magnets in the hydraulic reservoir for metal particles whenever the hydraulic system is drained. If metal particles are present, flush the entire system and add a new change of oil. [2]

5\. Use absolutely clean containers and funnels when handling hydraulic oil. [2]

6\. Cap and tag all hydraulic lines involved when removing any hydraulic component, and plug the ports of the removed components. [2]

7\. Disassemble all hydraulic components in spotlessly clean surroundings. Clean all metal parts in a clean mineral oil solvent, ensuring all internal passages are thoroughly cleaned. [2]

8\. Replace all O-rings and seals when overhauling any component. Lubricate all parts with clean hydraulic oil before reassembly, and use small amounts of petroleum jelly to hold O-rings in place during assembly. [2]

9\. Replace any lost hydraulic oil when completing the installation of the repaired component, and bleed any air from the system when required. [2]

10\. Keep all hydraulic connections tight. [2]

11\. Before working on the hydraulic system:

  • Lower forks to the ground.
  • Engage parking brake.
  • Shut down the engine.
  • Clean area around reservoir cap.
  • Loosen reservoir cap.
  • Remove key from starter switch. [1]

12\. Use a piece of cardboard or paper to search for leaks. Do not use hands! Before disconnecting lines, be sure to relieve all pressure. Before applying pressure to the system, ensure that all connections are tight. Do not apply pressure to a damaged line, hose, or fitting. [1]

13\. Change filters annually, or more often depending on operating conditions. [3]

14\. Maintain a sufficient quantity of clean hydraulic oil of the proper type and viscosity in the hydraulic reservoir. [3]

15\. Samples of hydraulic oil should be drawn from the reservoir and tested annually. These samples should be taken when the oil is warmed through normal operation of the system. [4]

4 source record(s)

Sources used for this answer

[1] Rough Terrain Scissors - SJ6826 RT, SJ6832 RT (167955) - Service Manual

Page 13

Open source document

Source excerpt

# Section 1 - Scheduled Maintenance (cont.) ## 1.2-3 Maintenance and Service Safety Tips (cont.) Hydraulic System & Component Maintenance and Repair 1 - Scheduled Maintenance # 1.3 Hydraulic System & Component Maintenance and Repair The following points should be kept in mind when working on the hydraulic system or any component: ## WARNING Escaping fluid from a hydraulic pressure leak can damage your eyes, penetrate the skin and cause serious injury. Use proper personal preotection at all times. 1. Any structure has limits of strength and durability. To prevent failure of structural parts of hydraulic components, relief valves which limit pressure to safe operating values are included in the hydraulic circuits. 2. Tolerance of working parts in the hydraulic system is very close. Even small amounts of dirt or foreign materials in the system can cause wear or damage to components, as well as general faulty operation of the hydraulic system. Every precaution must be taken to assure absolute cleanliness of the hydraulic oil. 3. Whenever there is a hydraulic system failure which gives reason to believe that there are metal particles or foreign materials in the system, drain and flush the entire system and replace the filter cartridges. A complete change of oil must be performed under these circumstances. 4. Whenever the hydraulic system is drained, check the magnets in the hydraulic reservoir for metal particles. If metal particles are present, flush the entire system and add a new change of oil. The presence of metal particles also may indicate the possibility of imminent component failure. A very small amount of fine particles is normal. 5. All containers and funnels used in handling hydraulic oil must be absolutely clean. Use a funnel when necessary for filling the hydraulic oil reservoir, and fill the reservoir only through the filter opening. The use of cloth to strain the oil should be avoided to prevent lint from getting into the system. 6. When re…

[2] Terex Square Shooters Series SS-624 / SS-636 / SS-836 / SS-842 / SS-1048 (manufactured after 4/30/1999) - Operator's Manual (PN 236492)

Page 54

Open source document

Source excerpt

# MAINTENANCE PROCEDURES # GENERAL SAFETY PRACTICES ## HYDRAULIC SAFETY ! WARNING Hot hydraulic oil can cause severe burns. DO NOT work on the hydraulic system if oil temperature exceeds 120 F°(49 c). Before ANYONE works on the hydraulic system: 1. Lower forks to the ground. 2. Engage parking brake. 3. Shut down engine. 4. Clean area around reservoir cap. 5. Loosen reservoir cap. 6. Remove key from starter switch. ## FLUID UNDER PRESSURE ! ## WARNING 4-4 Escaping fluid under pressure can penetrate the skin and cause serious personal injury. Use a piece of cardboard or paper to search for leaks. DO NOT use hands! Before disconnect- ing lines, be sure to relieve all pressure. Before applying pressure to the system, ensure that all connections are tight. DO NOT apply pressure to a damaged line, hose or fitting. If injured by escaping fluid, see a doctor at once. Proper medical treatment must be administered immediately. A serious infection or reaction can result without proper medical treatment.

[3] Rough Terrain Scissors - SJ9250 RT (163766) - Service Manual

Page 14

Open source document

Source excerpt

# Operator's Responsibility for Maintenance (cont.) ## Maintenance and Service Safety Tips (cont.) Service and Maintenance ## Hydraulic System & Component Maintenance and Repair The following points should be kept in mind when working on the hydraulic system or any component: SKYJACK, Page 14 ## WARNING Escaping fluid from a hydraulic pressure leak can damage your eyes, penetrate the skin and cause serious injury. Use proper personal protection at all times. 1. Any structure has limits of strength and durability. To prevent failure of structural parts of hydraulic components, relief valves which limit pressure to safe operating values are included in the hydraulic circuits. 2. Tolerance of working parts in the hydraulic system is very close. Even small amounts of dirt or foreign materials in the system can cause wear or damage to components, as well as general faulty operation of the hydraulic system. Every precaution must be taken to assure absolute cleanliness of the hydraulic oil. 3. Whenever there is a hydraulic system failure which gives reason to believe that there are metal particles or foreign materials in the system, drain and flush the entire system and replace the filter cartridges. A complete change of oil must be made under these circumstances. 4. Whenever the hydraulic system is drained, check the magnets in the hydraulic reservoir for metal particles. If metal particles are present, flush the entire system and add a new change of oil. The presence of metal particles also may indicate the possibility of imminent component failure. A very small amount of fine particles is normal. 5. All containers and funnels used in handling hydraulic oil must be absolutely clean. Use a funnel when necessary for filling the hydraulic oil reservoir, and fill the reservoir only through the filter opening. The use of cloth to strain the oil should be avoided to prevent lint from getting into the system. 6. When removing any hydraulic component, be sure to c…

[4] Rough Terrain Scissors - SJ6832 RTE (167574) - Service Manual

Page 13

Open source document

Source excerpt

# Section 1 - Scheduled Maintenance (cont.) ## 1.2-3 Maintenance and Service Safety Tips (cont.) Hydraulic System & Component Maintenance and Repair Section 1 - Scheduled Maintenance ## 1.3 Hydraulic System & Component Maintenance and Repair The following points should be kept in mind when working on the hydraulic system or any component: ## WARNING Escaping fluid from a hydraulic pressure leak can damage your eyes, penetrate the skin and cause serious injury. Use proper personal preotection at all times. 1. Any structure has limits of strength and durability. To prevent failure of structural parts of hydraulic components, relief valves which limit pressure to safe operating values are included in the hydraulic circuits. 2. Tolerance of working parts in the hydraulic system is very close. Even small amounts of dirt or foreign materials in the system can cause wear or damage to components, as well as general faulty operation of the hydraulic system. Every precaution must be taken to assure absolute cleanliness of the hydraulic oil. 3. Whenever there is a hydraulic system failure which gives reason to believe that there are metal particles or foreign materials in the system, drain and flush the entire system and replace the filter cartridges. A complete change of oil must be performed under these circumstances. 4. Whenever the hydraulic system is drained, check the magnets in the hydraulic reservoir for metal particles. If metal particles are present, flush the entire system and add a new change of oil. The presence of metal particles also may indicate the possibility of imminent component failure. A very small amount of fine particles is normal. 5. All containers and funnels used in handling hydraulic oil must be absolutely clean. Use a funnel when necessary for filling the hydraulic oil reservoir, and fill the reservoir only through the filter opening. The use of cloth to strain the oil should be avoided to prevent lint from getting into the system. 6…

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