SERVICE INFORMATION BULLETIN

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Rudolf French
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SERVICE INFORMATION BULLETIN Hydraulic System HS14-001 August 29, 2014 Guidelines for Cleaning a Contaminated Hydraulic System All Models Subject: Guidelines for Cleaning a Contaminated Hydraulic

1 SERVICE INFORMATION BULLETIN Hydraulic System HS August 29, 2014 Guidelines for Cleaning a Contaminated Hydraulic System All Models Subject: Guidelines for Cleaning a Contaminated Hydraulic System Page 1 of 9 MODEL APPLICATION: All models GENERAL INFORMATION: When diagnosing and repairing a contaminated hydraulic system, it is recommended that you contact Technical Services for assistance. This is especially recommended if the unit falls within warranty guidelines. Note: If the repair is to be considered for warranty, prior authorization by the warranty department is required before the repair is started. Warranty Dept. Authorization # Hydraulic contamination can have many symptoms which can lead to any combination of the following examples: Erroneous behavior of hydraulic functions, i.e. lift, tilt, auxiliary, steering and brakes Abnormal mast speeds on lift or lower Mis-staging of mast Excessive effort required to move the hydraulic control levers Abnormal noise from the truck when using hydraulics, steering, or brakes For the initial diagnosis, the following 4 steps should be followed: 1. Visual inspection of the hydraulic oil in the tank for metallic particles floating in the oil. 2. Lower a magnet into the hydraulic tank to check for any ferrous metal. 3. Block the mast following the proper procedures and remove the safety down valve from the bottom of the lift cylinders to check for metal contamination. 4. Remove the hydraulic return filter from the tank and cut it open for inspection. Refer to procedure starting on page 5. The above 4 steps should be utilized to determine if a hydraulic contamination exists and should take about 3 hours to perform. If metal is found during these diagnostics steps, the unit should be taken out of service and taken to a repair shop for further tear down and cleaning. Note: Contact Technical Services for advice, prior to disassembling any components. When a hydraulic system experiences a failure of a component and metal particles are introduced into the fluid, a thorough cleaning of the hydraulic system needs to be performed. Merely replacing the failed component and the hydraulic oil and filters is not going to ensure the problem has been corrected.

2 Subject: Guidelines for Cleaning a Contaminated Hydraulic System Page 2 of 9 The hydraulic fluid is filtered on the suction side and return side of the hydraulic system. In the event of a system component failure, the contamination can be circulated throughout the system before going back to the hydraulic tank filters. It is important to identify the failed component(s) and completely clean the system to prevent ongoing hydraulic issues. For example: If metal is found in the steering control valve, then the steer cylinder and the hydraulic oil control valve would need to be checked for contamination. If the steering cylinder was okay, but the metal was found in the hydraulic oil control valve, then the entire system would need to be checked. This is due to the hydraulic oil control valve dispersing oil to the entire system. REPAIR INFORMATION: Use the following steps to track and document parts and labor used during the hydraulic contamination repair. Hydraulic Attachments and Auxiliary Valves: If attachment(s) are used on the unit with the failure, each and every attachment should be inspected that may have come in contact with the unit which had the failure. Also, any other units which have used an attachment which was on the failed unit should be inspected for metal contamination. All auxiliary options should be cleaned and inspected Flow/Auxiliary Valve, Labor Attachment Cylinders, Labor Attachment Hoses, Labor Attachment Rotator/Motor, Labor System Clean Up Procedures: Drain the hydraulic oil from the tank and remove the filters. The inside of the tank will need to be cleaned. Labor The hydraulic oil cooler in the radiator or additional coolers should be flushed to ensure no contamination is present. Labor Radiator: Replaced or Cleaned If the unit is equipped with a hydraulic accumulator, it should be inspected, flushed, and pressure tested to verify it is reusable. Labor Accumulator: Replaced or Cleaned Remove the hydraulic pump from the unit and disassemble to determine the condition of the pump. If the internal walls of the pump look scored, or a broken gear is visible, the pump will need to be replaced. Labor Pump: Replaced or Cleaned While the pump is out of the unit, the torque on the crankshaft pulley bolt should be checked on units with a pump driveshaft. A malfunctioning pump can put an added amount of stress on the crankshaft pulley bolt and cause it to come loose. Also, the keyway on the crankshaft should be checked if the bolt was found to be loose. Refer to the appropriate engine manual for the proper torque for the crankshaft bolt. Labor If the pump has to be replaced due to internal damage, then the hydraulic oil control valve will need to be inspected. This is due to the metallic pieces from the pump will be transported to the oil control valve via the hydraulic oil.

3 Subject: Guidelines for Cleaning a Contaminated Hydraulic System Page 3 of 9 Hydraulic Control Valve: Determine if the control levers for the hydraulic controls move freely. If there is any binding in the levers, a spool could be sticking from the contamination and that section of the valve will need to be replaced. The valve should be completely disassembled and inspected for any damage or contamination. If any damage is found, the valve will need to be replaced. The pressure relief valve and the flow regulator valve should be inspected for any sign of contamination or scoring. If any damage is found, the component should be replaced. Labor: Hydraulic control valve: Replaced or Cleaned Flow Divider Valve (within the hydraulic control valve): If any metal contamination or scoring is found in the flow divider valve, then the steering circuit will need to be examined for metal contamination. Steering System: The steer cylinder should be completely disassembled and inspected for any contamination or damage. Labor The lines going from the steering valve to the steer cylinder should be thoroughly cleaned if contamination was found in the steer cylinder. Labor If contamination was found in the steer cylinder, then the steering valve may also be contaminated with particles. The valve may need to be replaced. Labor If the steer cylinder was found to be free of contamination, along with the flow divider valve, then checking the steering valve internally would not be required. Labor Steering Cylinder: Replaced or Cleaned Steering Valve: Replaced or Cleaned Brake System: If so equipped, the brake booster should be disassembled and inspected for any contamination or damage. The flow of oil to the booster comes directly from the hydraulic oil pump. Labor Disassembly of the wheel cylinders to inspect for debris is recommended. Labor Brake Booster: Replaced or Cleaned Wheel Cylinders: Replaced or Cleaned Lift /Tilt Cylinders: The cylinders should be completely disassembled and checked for any contamination or damage. Labor Lift Cylinders: Replaced or Cleaned Tilt Cylinders: Replaced or Cleaned

4 Subject: Guidelines for Cleaning a Contaminated Hydraulic System Page 4 of 9 Metal Tubing/Rubber Hydraulic Hoses: The lines going to and from the failed component will need to be inspected. Steel tubing can easily be flushed, but metal particles can become embedded in the rubber hoses causing issues at a later time. It is important to determine the condition of the rubber hose before spending a lot time trying to clean the contamination out of the hose. Short hoses can be visually inspected by holding straight, and back lighted. Rubber hoses should be flushed in both directions. Mast Hoses, Labor Brake Lines, Labor Steering Hoses, Labor Chassis Hoses, Labor After the repair has been completed and during the next PM, the hydraulic oil and filters should be changed to ensure the contamination issue has been resolved. Total labor time: Component which caused the metal contamination: NOTES:

Subject: Guidelines for Cleaning a Contaminated Hydraulic System Page 5 of 9 Disassembling a Hydraulic Return Oil Filter for Inspection: Note: Never

Doing this will add contamination into the filter and can easily be misdiagnosed as a hydraulic contamination problem.

5 Subject: Guidelines for Cleaning a Contaminated Hydraulic System Page 5 of 9 Disassembling a Hydraulic Return Oil Filter for Inspection: Note: Never grind or hacksaw into the can of a filter. Doing this will add contamination into the filter and can easily be misdiagnosed as a hydraulic contamination problem. There are special tools designed to cut open a filter that are designed similar to a pipe cutter. These are also good to use. If you do not have a specialized filter cutting tool then you can follow the approved grinding method described below. Approved grinding method: 1. Drain excess oil

pan under it to catch any oil that may come out

6 Subject: Guidelines for Cleaning a Contaminated Hydraulic System Page 6 of 9 2. Tape or cover the inlet and outlet 3. Secure filter in a vise and position a catch pan under it to catch any oil that may come out when the filter comes apart 4. Get a grinder and wear proper PPE for grinding

Subject: Guidelines for Cleaning a Contaminated Hydraulic System Page 7 of 9 5.

Keep repositioning the filter in the vise as needed to continue the grinding

7 Subject: Guidelines for Cleaning a Contaminated Hydraulic System Page 7 of 9 5. Locate the fold of the filter end lip that joins the end of the filter to the can of the filter. 6. Grind the fold down till you see the separate lines of the can and end piece. 7. Keep repositioning the filter in the vise as needed to continue the grinding process until grounding through the fold the entire way around the filter. At this point the filter will come apart and trapped oil may drain out

Subject: Guidelines for Cleaning a Contaminated Hydraulic System Page 8

You can now pull the end with the paper filter attached from the can 9.

and good place to start the inspection one pleat at a time. 10.

8 Subject: Guidelines for Cleaning a Contaminated Hydraulic System Page 8 of 9 8. You can now pull the end with the paper filter attached from the can 9. The paper element will have a metal splice which can serve as a marker and good place to start the inspection one pleat at a time. 10. Pull the pleats apart to see if there is any contamination. Note: Latex or nitrile gloves are recommended as the element will still be oil soaked.

Subject: Guidelines for Cleaning a Contaminated Hydraulic System Page 9 of 9 11. Check inside every pleat and photograph or save any contamination that is found.

9 Subject: Guidelines for Cleaning a Contaminated Hydraulic System Page 9 of Check inside every pleat and photograph or save any contamination that is found. A magnet can be used to help find ferrous contamination. 12. A few particles are normal. If it is thought that there is excess contamination present then contact the Technical Services department and get instructions on how to proceed if the truck is in the warranty period.

k. Components not properly adjusted. Refer to machine technical manual for proper adjustment of components.

k. Components not properly adjusted. Refer to machine technical manual for proper adjustment of components. General Troubleshooting Charts General Troubleshooting Charts Use the charts on the following pages to help in listing all the possible causes of trouble when you begin diagnosing and testing of a machine.