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I have a CAT 225 I need to know how to set the pressures.

It seems to have an...
I have a CAT 225 I need to know how to set the pressures. It seems to have an issue with the stick coming in slow & even stopping when it's vertical then picking up & going again. The boom seems to drop very fast almost uncontrolable. Also, it seems to take off very fast one way but takes off normal the other way. It walks fine & in a straight line. I need to know where to plug my gauges & what to check & how to adjust the pressure's and/or fine tune.
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Answered in 10 minutes by:
12/30/2012
Mechanic: catmastertech, Technician replied 9 years ago
catmastertech
catmastertech, Technician
Category: Construction and Road Equipment
Satisfied Customers: 3,994
Experience: Field service technician for CAT 19 years.
Verified

catmastertech :

If you have the serial number, I will try to find something to help.

catmastertech :

Have you considered ordering a manual from CAT?

Customer:

76u03900

Customer:

can l get one online?

catmastertech :

Sometimes you can find an old manual on ebay or another source. It may not be complete or as up to date as a new print so, beware. CAT dealers can usually get one printed in about a month, average cost for the complete manual can be over $1000. Worth the cost when you compare it to a dealer service call for a couple of days.

catmastertech :

I have only done a few repairs on these machines. Most of it has been on the undercarriage and travel valves. Never had to adjust the pumps or check this particular problem. I do have a testing guide the may help get you started on the problem. It sounds like you have a signal problem to the pumps. Follow the testing and check the summing valve closely. Verify the signal lies from each valve to the summing control is not damaged or blocked.

catmastertech :

Testing and adjusting 225 hydraulic system <<<click here.

catmastertech :

If you run into a problem, I will be glad to find more details to help.

catmastertech :

Hopefully this can help you get started checking the machine. Thanks for using JustAnswer!

Customer:

so far your imput and info have been a tremendos help ,however we are having trouble with locating the test ports and correct valves from the limited illustrations provided even though we no have a set of service / repair manuals.could there be some better refrences?

catmastertech :

Which test do you need more information about? I will see if I can locate some better images to identify the port.

catmastertech :

I know this pictures are not that clear. It is copied from old books and was done a few years ago. Imaging has improved today but, the books are not likely to be updated.

Customer:

I need to run pressure tests on the pilot /relief valves.

catmastertech :

I would you the port in the end of the control valve. You could also use a T-fitting in line to tap into the pressure.

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catmastertech :

You will need to tap each line to see the pilot pressure for each spool. A gauge will be needed on each end of the spool. I guess you may already know this, just want to be sure. I will send a picture of the valve layout too.

catmastertech :

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catmastertech :

CONTROL VALVES IN MAIN OIL SYSTEM
9. Control valve (right track). 10. Control valve (bucket). 11. Control valve (boom). 12. Control valve (stick crossover) boom crossover valve is located at opposite end. 15. Control valve (swing). 16. Control valve (left track). 17. Control valve (stick). 20. Overspeed valve (right track). 21. Blocker valve. 22. Overspeed valve (left track).

catmastertech :

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catmastertech :

PILOT CONTROL VALVE AND LINES (Boom and Bucket)
1. Oil line to supply of pilot oil from safety valve. 2. Oil line for pilot pressure to control valve for boom RAISE. 3. Oil line for pilot pressure to control valve for bucket CLOSE. 4. Oil line for pilot pressure to control valve for boom LOWER. 5. Oil line for pilot pressure to control valve for bucket OPEN. 6. Oil line for return oil to tank.

catmastertech :

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catmastertech :

PILOT CONTROL VALVE AND LINES (Boom and Bucket)
1. Oil line to supply of pilot oil from safety valve. 2. Oil line for pilot pressure to control valve for boom RAISE. 3. Oil line for pilot pressure to control valve for bucket CLOSE. 4. Oil line for pilot pressure to control valve for boom LOWER. 5. Oil line for pilot pressure to control valve for bucket OPEN. 6. Oil line for return oil to tank.

catmastertech :

Control Valves In Pilot System


The pressure of the pilot oil in lines (1) and (12) is held at approximately 2300 kPa (335 psi) by the action of the relief valve for pilot pressure. (See PUMP FLOW AND PRESSURE CONTROL). Pilot pressure of 2300 kPa (335 psi) will move any spool in a main control valve to its full travel. This lets maximum oil flow from the main system pumps go to a cylinder or motor. The rate of main system oil flow through any main control valve is controlled by a change in the pressure of the pilot oil that is used to activate the valve. Pilot valves (15) and (28) have the capacity to cause a controlled increase or decrease of pilot oil pressure to the main control valves.



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[IMAGE][SRC][/SRC][ALT][/ALT][WIDTH]100[/WIDTH][HEIGHT]100[/HEIGHT][STYLE][/STYLE][/IMAGE]
PILOT CONTROL VALVE AND LINES (Boom and Bucket) 1. Oil line to supply of pilot oil from safety valve. 2. Oil line for pilot pressure to control valve for boom RAISE. 3. Oil line for pilot pressure to control valve for bucket CLOSE. 4. Oil line for pilot pressure to control valve for boom LOWER. 5. Oil line for pilot pressure to control valve for bucket OPEN. 6. Oil line for return oil to tank.


Pilot valves (15) and (28) are the same. Each has one control lever and two spools. Movement of either spool controls pilot pressure to the end of a spool in the main control valves. This control of the pilot oil pressure gives controlled movement of the spool in the main control valve and modulation of the implement it controls.



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[IMAGE][SRC][/SRC][ALT][/ALT][WIDTH]100[/WIDTH][HEIGHT]100[/HEIGHT][STYLE][/STYLE][/IMAGE]
PILOT CONTROL VALVE AND LINES (Stick and Swing) 7. Oil line for pilot pressure to control valve for stick OUT. 8. Oil line for return oil to tank. 9. Oil line for pilot pressure to control valve for swing RIGHT. 10. Oil line for pilot pressure to control valve for stick IN. 11. Oil line for pilot pressure to control valve for swing LEFT. 12. Oil line for supply of pilot oil from safety valve.


When spools (13), (14), (26) and (27) are in the NEUTRAL position, oil flow is stopped and oil pressure at oil passages (18) and (31) is at pilot system pressure of approximately 2300 kPa (335 psi).


When spool (13) is moved up, passage (19) and slot (22) open a way for oil flow from passage (18) into passage (21). Oil flow also goes through passage (24) and slot (22) to passage (23) for return to tank. This arrangement of oil flow makes a pressure in passage (21) of approximately 415 kPa (60 psi) after spool (13) has moved 1.6 mm (.062 in.).


When spool (13) is moved more in the same direction, the area of the opening between slot (22) and passage (18) becomes larger. At the same time, the area of the opening between slot (22) and passage (24) becomes smaller. This causes an increase in the pressure in passage (21). The oil pressure in passage (21) increases to approximately 1720 kPa (250 psi) after spool (13) has moved 6.4 mm (.250 in.). When the spool movement is more than 6.4 mm (.250 in.), the area between passage (21) and passage (23) is closed off and oil flow to passage (23) is stopped. Oil pressure in passage (21) increases to the same value as the pilot system.


When spool (13) is pushed down, the oil pressure in passage (16) follows the description for the increase in pressure for passage (21).


Oil line (4) connects passage (21) and the inlet opening in the cover on the end of the main control valve for boom LOWER. The pressure of the pilot oil in the cover that moves the main spool against the force of its springs, is the same as the pressure in passage (21) that is controlled by the movement of spool (13).

catmastertech :

OOPS- forgot to remove links- they will not work anyway, just ignore them.

catmastertech :

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catmastertech :

PILOT CONTROL VALVE (Boom and Bucket) 13. Spool for boom control. 14. Spool for bucket control. 15. Pilot valve for control of the boom and bucket circuits. 16. Oil passage to line (2) for boom RAISE. 17. Oil passage to line (3) for bucket CLOSE. 18. Oil passage to line (1) for supply of pilot oil. 19. Oil passage in the spool. 20. Oil passage to line (5) for bucket OPEN. 21. Oil passage to line (4) for boom LOWER. 22. Slot in the spool. 23. Oil passage for return oil to tank. 24. Oil passage in the spool. 25. Oil passage for return oil to tank.


Pilot oil pressure of about 145 kPa (21 psi) will cause the main spool to move 4.0 mm (.156 in.) against the force of the inner spring and make contact with the outer spring. Pilot oil pressure of about 415 kPa (60 psi) is needed to move the main spool against the force of both springs to a position where main system oil starts through the valve to the cylinder. When spool (13) is in the position to start a controlled pressure increase from 415 to 1720 kPa (60 to 250 psi), the main spool is in the position to start to control the rate of flow through the main control valve from zero to full pump output. As spool (13) is moved to cause a pressure increase to 1720 kPa (250 psi), the main spool moves through the range where rate of flow of the oil in the main system is controlled. The movement of spool (13) makes contact with a second spring in the pilot valve and the added force gives the operator a "feel" of the operation during the changes in rate of flow.

catmastertech :

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catmastertech :

PILOT CONTROL VALVE (Stick and Swing)
26. Spool for swing control. 27. Spool for stick control. 28. Pilot valve for control of stick and swing circuits. 29. Oil passage to line (9) for swing RIGHT. 30. Oil passage to line (7) for stick OUT. 31. Oil passage to line (12) for supply of pilot oil. 32. Oil passage in spool. 33. Oil passage to line (11) for swing LEFT. 34. Oil passage to line (10) for stick IN. 35. Slot in spool. 36. Oil passage to line (8) for return oil to tank. 37. Oil passage in spool. 38. Outlet to tank.

catmastertech :

That is what I have about the pilot controls. Let me know if you need more help. Thanks, Donnie

Customer:

I'm specfically looking for a pilot controlled relief valve.

catmastertech :

OOPS- my bad! I will see if I can find the correct info. Sorry.

catmastertech :

Just to be clear- you want to set the pressure for the pilot relief or the main control valve pressure relief?

Customer:

pilot relief first then ill goto the main.

catmastertech :

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catmastertech :

This tee should be in the supply line to the travel valve.

catmastertech :

Remove the front pan under the cab to access it.

catmastertech :

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catmastertech :

Item 4 is the relief valve. It is mounted on the side of the hydraulic tank.

catmastertech :

I think you will need to remove a hood section to access it.

catmastertech
catmastertech, Technician
Category: Construction and Road Equipment
Satisfied Customers: 3,994
Experience: Field service technician for CAT 19 years.
Verified
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Category: Construction and Road Equipment
Satisfied Customers: 3,994
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