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Cat 325L no hydraulic power

T

TVA

Senior Member
r20d12 said:
If they would take me whale watching we could work something out Lol. Ive actually considered driving up there just cuz it looks so purdy on tv
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Maybe little too late than s year, unless you like cold weather!
 
r20d12

r20d12

Well-Known Member
Just remembered... (There's nearly 30 years of tractor knowledge to shuffle through)
I once had a trackhoe that had a plugged screen in the pilot passage in the center of the main control valve. It only let the hydraulics of one pump work.
TVA said:
I know, but my thinking was maybe the flow so low that drain orifices cannot restrict flow to build up pressure.

So all day yesterday I was looking at pictures and diagrams of A8VO and looking at the gear drive, thinking maybe something happened to it and he lost drive three piston pumps and retain only to gear pump but now I know that it is impossible.
Now I have another theory about restricted suction, as he has three piston pumps (when ch not known for good suck ability) which produce almost no flow, and one gear pump ( with better suck ability and lower displacement) which seems to be doing OK.
And that’s beside not knowing what is pilot pressure at pilot control valves.
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"Suckability" you should write service manuals!
 
T

TVA

Senior Member
r20d12 said:
Just remembered... (There's nearly 30 years of tractor knowledge to shuffle through)
I once had a trackhoe that had a plugged screen in the pilot passage in the center of the main control valve. It only let the hydraulics of one pump work.


"Suckability" you should write service manuals!
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Which reminds me: I took a brief look at the Kobelco SK 120 on my way back from another job, that POS was doing half ass job, seems to ran too high of a negcon pressure. Maybe it need the orifices cleaned out. Also was hanging at arm cylinder bottomed out.
 
r20d12

r20d12

Well-Known Member
TVA said:
Which reminds me: I took a brief look at the Kobelco SK 120 on my way back from another job, that POS was doing half ass job, seems to ran too high of a negcon pressure. Maybe it need the orifices cleaned out. Also was hanging at arm cylinder bottomed out.
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Arm cylinder hanging sounds like main spool hung due to trash in the system. Maybe arm cylinder coming apart?
 
r20d12

r20d12

Well-Known Member
TVA said:
I was born in Ukraine, lived in Seattle for 20 years, then moved to Mobile - talking about cultural shock!
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Wow! Yeah! You went from snow and beautiful women to rain and ugly hippies to warmth and beautifull women!
 
T

TVA

Senior Member
r20d12 said:
Arm cylinder hanging sounds like main spool hung due to trash in the system. Maybe arm cylinder coming apart?[/

By hanging I meant not going to neutral after you let go of joystick, didn’t have time to check pilot for hang ups, but high and slow the drop negcon pressure is either plugged orifices or these hanging problems hint me towards spools leakage.
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T

TVA

Senior Member
r20d12 said:
Wow! Yeah! You went from snow and beautiful women to rain and ugly hippies to warmth and beautifull women!
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I wouldn’t count what goes on in Seattle - rain! It’s more likely he 9 months of non stop drizzle, followiled by 3 months you f scorching heat!
 
T

TVA

Senior Member
Hello rclay1981! Want to apologize for highjacking your thread again. I’m afraid I’m going to get scalded by others but my method is remove and plug the hoses and try to use the machine. If your engine boggs down then your PRV is leaking and pump is good. If not - then the problem with the pump. Provided, of course, that you have good pilot pressure all the way to control valve.
 
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T

TVA

Senior Member
TVA said:
Hello rclay1981! Want to apologize for highjacking your thread again. I’m afraid I’m going to get scalded by others but my method is remove and plug the hoses and try to use the machine. If your engine boggs down then your PRV is leaking and pump is good. If not - then the problem with the pump. Provided, of course, that you have good pilot pressure all the way to control valve.
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Or you can find 0-10 ampmeter, connect it PRV solenoid in series, at in to PRV signal line with 0-600 or digital gauge, start operating the machine and compare changes of current corresponds with changes of pressure. Or find some kind of current regulating device disconnect solenoid from the machine’s circuit change the current using the device and watch change in pressure.
 
R

rclay1981

Member
I capped all three of the lines it didn’t change anything. Their Was zero pressure at the PRV valve with the lines hooked up or capped off while testing. Pilot pressure is 500 psi at test point and 425 psi on top the control valve. I did notice today that the pilot pump line was getting extremely hot really fast like it has internal leakage.
What do you think the chances of the main pressure relief valve going bad all of a sudden is?
 
T

TVA

Senior Member
I would say something but lately it seems I caught a case of “foot in mouth” disease!!!
 
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