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20 Cards in this Set
- Front
- Back
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How can hydraulic fluid that comes in contact with your skin for prolonged periods harm you |
It can cause cancer |
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How can a pinhole hydraulic leak harm you |
High pressure fluid can pierce your skin and enter your bloodstream, which in turn can cause gangrene |
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Why should a dynamic seal have some leakage |
For lubrication |
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What condition must the surfaces of a metal-metal seal be in before assembly |
It must be flat with no scratches |
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What tightening pattern must you use to avoid distortion when bolting rectangular surfaces together |
Spiral from the center |
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How can you determine the correct torque value when you assemble a hydraulic component |
Consult the service manual |
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What is the main purpose of a backup ring for an o-ring? |
It supports the o-ring against extrusion |
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What type of sealant should you use on tapered pipe threads in hydraulics |
Liquid sealants |
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Which should have the tighter fit |
Static o-ring |
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What type of piston rings should you use when no cylinder creep can be tolerated |
Non-metallic |
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What is the basic purpose of an accumulator |
It adds pressurized fluid to the system when needed |
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Name three additional purposes of an accumulator |
Absorb shock Even out pulsations Allow for thermal expansion |
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What safety precaution must you take when there is an accumulator in the system |
Completely depressurize and block it out of the circuit before you disconnect any piping or disassemble the accumulator |
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Name three unloading methods for an accumulator |
Manual bleed down Solenoid bleed down Vented relief valve |
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Which type of gas must be used in a gas accumulator |
Use inert gas such as nitrogen |
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The precharge should never be less than ______ of max system pressure when the accumulator is empty. |
The precharge should never be less than 25% of maximum system pressure when the accumulator is empty |
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When is the pre-charge put into an accumulator |
When the accumulator is empty |
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What is the main disadvantage of gas or spring type accumulators |
They cannot maintain a constant pressure as they discharge |
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Name three advantages of a spring type accumulator |
It can operate in any position It is compact There are no leaks No pre-charge is needed |
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Why are air and oxygen not used in gas-filled accumulators? |
If they contact oil through a leak in the bladder, they cause an explosion |
