LIEBHERR 932 Pilot Circuit Down

SMOKINMAC · Dec 20, 2017

Please Help!
The Pilot hydraulic system is not working.
The Safety Solenoid Cut OFF is not the issue, it has been by-passed, and there is hydraulic pressure on the pilot line leaving the Pilot Gear Pump.

My Question is, IS there any other cut-offs, either Electric Solenoid, or Air, etc in the pilot system. Looking for any other shut-offs down stream of the Gear Pump.

The Hydraulic Pilot Control System will go dead for no apparent reason and this time it will not come back to life, looking for causes.

Would greatly appreciate any help. Thanks

markct · Dec 20, 2017

When you say the safety solenoid cutoff
I assume you mean the armrest or stick
by the door, when you say bypassed how
so are you talking, bypassed the switch
and direct wired the solenoid to be live
always, or physically removed it. If
electrical bypassed it there's a good
chance the solenoid failed or jammed.

NCWayne · Dec 20, 2017

I'm not that familiar with Liebherrs but given general knowledge on various other brands, I've got to agree with Markct. If it has an electric solenoid valve simply bypassing the switch that turns it on doesn't insure it is actually going to work. I'd almost bet the coil has burned out and the valve isn't actually working. Unfortunately there's probably no way to bypass the actual valve completely as they are typically part of a larger valve body. Good luck.

SMOKINMAC · Dec 21, 2017

The Solenoid Valve itself has been by-passed / removed from the system. Hydraulic line goes direct from Gear pump to Pilot Line.

Looking for any other electric or air valves in the pilot system that would shut it down. Say a Oil pressure sensor circuit, Temperature circuit, etc. Thanks

NCWayne · Dec 22, 2017

The only thing I can think of that would cause the circuit to go dead would be either the pump stops putting out, or the there is a pilot system relief that's popping and causing the pressure to drop. Beyond that, sorry, but I don't know what else to tell you.

markct · Dec 23, 2017

Ok you say it goes to the pilot line,
where's that go? Directly to the
controls? Have you checked for flow and
pressure at the joysticks? Also for flow
to return? Many pilot systems have a
small "stone" filter before the
joysticks. Also there should be a relief
and or regulating valve in the circuit,
usually incorporated with the solenoid
valve but could be separate. Did someone
remove that as well?

SMOKINMAC · Dec 25, 2017

(quoted from post at 14:02:07 12/23/17) Ok you say it goes to the pilot line,
where's that go? Directly to the
controls? Have you checked for flow and
pressure at the joysticks?

Also for flow
to return? Many pilot systems have a
small "stone" filter before the
joysticks. Also there should be a relief
and or regulating valve in the circuit,
usually incorporated with the solenoid
valve but could be separate.

Did someone
remove that as well?

[/b]1. No pressure at Joysticks
2. No other mods to system.
3. I am wondering if a check valve or Relief valve in the control circuit has failed. If a relief valve then that is siphoning off the pressure, or if a check valve not as sure how this wold affect circuit. I wonder if a check valve could fail where it blocks flow in the INTENDED direction??

Thanks for your replies and help.

LIEBHERR 932 Pilot Circuit Down

SMOKINMAC

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markct

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NCWayne

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SMOKINMAC

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NCWayne

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markct

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SMOKINMAC

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