most companies make very few preventive maintenance checks such as: oil level filter condition leaks...

Welcome To

HydraulicsFor The

LONG TERM

Copyright, 2012 © GPM Hydraulic Consulting, Inc.

• Most Companies Make Very Few Preventive

Maintenance Checks Such As: Oil LevelFilter ConditionLeaksPump And Motor Coupling

Hydraulics For The Long Term

Forklift Maintenance Checklist

How To Improve The Longevity Of Your

Hydraulic System

• Testing of the pump(s) to determine if the proper volume is being delivered to the system. By making this test regularly the pump can be replaced on a down day and not when it fails and interrupts production.

• Checking the accumulators to make sure they are properly pre-charged which is necessary to achieve the desired speed to maintain production.

How To Improve The Longevity Of Your Hydraulic System

• On any given hydraulic system, there should be some lines that are hot (above 130 degrees), warm (100-130 degrees), and cool or at ambient temperature. By checking the temperature of these lines on a regular basis a component failure can be found before the system fails completely.

• One of the main issues in a hydraulic system is leakage. One drop of oil that drips once per second will lose 405 gallons a year. If leakage is occurring there is a reason for it.


Hydraulic System

• One of the biggest problems in systems today is that the pressures are out of adjustment which causes excessive force, heat, leakage and wasted electrical energy. You will identify any pressure setting issues and many times correct them during the checks.

• Check to verify that the pipe and tubing clamps are properly spaced and are of the proper type. Make sure that the hoses are properly installed to prevent pre-mature failure and oil loss.


Hydraulic System

• Check the condition of the filters if a visual or electrical indicator is available.

• Verify that the air and water heat exchangers are operating properly to reduce the oil temperature to an acceptable level. If the oil temperature is above 140 degrees then oil will start breaking down causing

sludge and varnish in the system.


Hydraulic System

• Check the condition of the breather cap on the reservoir.

• Sound checks to determine pump cavitation, aeration or valves bypassing in the system.

Hydraulic Reliability Checks That Should Be Made On A Regular Scheduled Basis

1. Record the maximum and minimum pressures in the system.

Max PSI

Min PSI

Hydraulic Reliability Checks

2. Record the oil temperature in the reservoir. If there is no thermometer or unreadable, use a temperature gun.

°F


3. Check the relief valve tank line for heat. The tank line should be considerably cooler than the inlet line.

°F

Compensator Set Higher Than The Relief Valve

Adjusting The PressuresSetting a Compensator In a System With a Relief Valve

Hydraulic Reliability Checks4. Check the temperature of the pump suction line and case drain

line.

Suction Line °F Case Drain Line °F

Pressure Compensating Piston Pump

Case Drain Line

Suction Line

There are two methods of checking case drain flow:

• Run the case drain flow into a container of known size and time it

Checking The Pumps Case Drain Flow

• A flow meter may be permanently installed in the case drain line.

Checking The Pumps Case Drain Flow

Hydraulic Reliability Checks5. Check the temperature of the accumulator shell for heat.

Top Of Shell °F Bottom Of Shell °F

Checking The Accumulator

Checking the pre-charge with a charging rig.

Gas Chuck

Bleed Valve

Hose Connection


6. When was the last date the return filter was changed? Check the visual indicator for the filter condition.


7. Check the condition of the breather caps. When was the last time they were changed?


8. Check the oil level in the reservoir. A sight glass is usually mounted on the side of the tank.


9. Check the condition of the heat exchanger. Are the fins clean and is there good air flow?

Hydraulic Reliability Checks10. Check the condition of the hydraulic hoses. Are any rubbing or over

4-6 feet in length? If so, hose protectors should be placed over the rub points.

Hydraulic Reliability Checks11. Check the condition of the pipe clamps and make sure the

proper clamps are used. Clamps should be spaced every 5 – 8 feet and within 6” of where the pipe terminates.

Proper Clamp

Improper Clamping

Hydraulic Reliability

• These are just 11 checks that should be made on a regular scheduled basis.

• Depending on the hydraulic system, there can be as many as 25 reliability checks.

• A Hydraulic System Reliability Checklist should be developed for all your hydraulic systems.

Questions

1. Force = _____ x _______

Hydraulic IQ TestHow Much Do You Really Know About Hydraulics?

2. Pascal’s Law states that pressure in a confined body of fluid will act _______ in all directions.

Hydraulic IQ Test

3. Power is the ____ at which work is done.

Hydraulic IQ Test

4. Pressure in a hydraulic system is caused by a __________ to flow

Hydraulic IQ Test

5. There are six reasons why a valve solenoid can fail. Can you name one?

Hydraulic IQ Test

6. When a solenoid is checked with an ohmmeter and the reading is less than 50 ohms, what does this mean?

Hydraulic IQ Test

7. What five characteristics does the valve symbol below have?

Hydraulic IQ Test

8. Which valve center position would be best to use with a fixed displacement pump?

Hydraulic IQ Test

9. If you were replacing the pilot valve on a solenoid controlled hydraulic piloted valve, which center position would be correct?

Hydraulic IQ Test

10. Which valve is larger?

Hydraulic IQ Test

11. What two checks would you make to be sure an accumulator used for volume is operating properly?

Hydraulic IQ Test

12. If no heat is felt on a bladder accumulator, one of two things has happened. They are:

Hydraulic IQ Test

Hydraulic IQ Test

13. The relief valve serves two functions in a hydraulic system with a variable displacement pump.

They are:

Hydraulic IQ Test

14. What is usually the number 1 reason why pumps cavitate?

Hydraulic IQ Test

15. True or False: A particle of contamination whose size is the diameter of a human hair is not harmful to a hydraulic system.

Hydraulic IQ Test

16. What happens to the electric motor current draw when a pump compensates?

most companies make very few preventive maintenance checks such as: oil level filter condition leaks...

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