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Genie S85 S/N 1708 year 1999 - Hydraulic problem

usedequipment

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Hi guys,
We bought 1 Genie S85 S/N 1708 4WD year 1999 and we have 1 problem with Hydraulic system.
When we operated the functions, if there was no voltage went to Valve item G Valve G.jpg, all of the functions didn't operate.
If we bypass the electronic signal and provide electric to Valve G, we can operate the functions. However, the hydraulic temperature will increase rapidly and after 30mins - 1hour the machine will stop working.
We have checked 1 Genie S85 year 2000 S/N 1895 and found out the Valve G received electric only when we lower the main boom. All remaining functions, the valve received no electric.

We tried to replace the valves with similar valves but couldn't fix the problem.
We have also tested the wiring diagrams and made sure it stays the same with Genie S85 year 2000.
Did anyone face the same problem with us ??
We have been fixing this machine for half a year but didn't make and progress.
We also contacted local Genie Dealer but they didn't support used machine.
Here is the schematic of the hydraulic system ( we downloaded on Genie).Valve G location.jpg
 

lantraxco

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Can't really read the schematic, but enough of it I'm pretty sure that "G" is the dump valve, it has to close when any function is engaged to provide pressure.
When you activate the valve with your bypass wire of 12V, it closes and if you are not using any functions, the oil flow is bypassing through the relief valve, which is the reason you have so much heat. With the valve not activated does the steering and drive still function?

Does this have extendable axles and are they in fact extended fully before attempting to operate?
 

usedequipment

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Dear lantraxco,
Very appreciated you reply. This machine has extendable axles and we extracted the axles before operating. All functions didn't operate unless Valve G received voltage.
We tested with another Genie S85 year 2000, Valve G only received voltage when lower the main boom. Others functions ( include steer & drive), Valve G didn't received voltage. The machine worked normally.
On the schematic and service manual Valve G named Solenoid Valve-no poppet - Hydraulic Limit Switch. I don't understand the hydraulic limit switch function in the machine ? is it the limit switch of the axles ???
Please check the full 4WD schematic :
koV0GXl.jpg

Valve types :
Manifold1.jpgManifold 2.jpgAxle dump.jpgSteer.jpg
Valve G and Valve SS are connected ( if valve G receives voltage, Valve SS also receives voltage).
 
Last edited:

lantraxco

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These manuals are very poor in my opinion. I think I am beginning to somewhat understand some of the systems here.

I think this is mostly an electrical problem, may I make some suggestion?

I think Limit switch 2 is your problem, this is the limit switch on the side of the boom that is activated by the cable track I think? It senses that the boom is retracted to a certain point or shorter. The activating wire for the boom down function ties in after Limit switch 2, all other feeds are previous to it, so I am guessing either the switch is faulty or you have a broken wire.

Please test Limit switch 1, which is the boom raise switch, check that power is present on at least one wire, the switch functions, and it is in proper position.
Please do the same with Limit switch 2, which is the boom extend switch, same checks.
With the engine running, boom down and in, you should have power going in and out of both limit switches?

If the switches check out, please do these tests with the engine running:
Test TB 46 for +12V If there is no power, check for a break in the white wire from the alternator to this point.

Once you have 12V at TB46 please test TB42 for +12V, this test point is after the Limit switch 1, the boom must be fully down.

Again once you have 12V at TB42, if the machine is not now functioning continue on....
Remove relay CR20, test for +12V at terminal 85, this is after Limit switch 2, the boom must be fully retracted. If there is no power, try testing while activating the boom down switch, this should provide +12V since you state that this function does work. There may be a broken wire between Limit switch 2 and this point, schematic says "Red 6".

I hope some of this is helpful. In addition there are two hydraulic limit valves one on each axle that when both axles are fully extended, if they are functioning correctly and properly adjusted, send 350 psi pressure to valve "M" in the manifold which performs the same function as valve "G" closing off the dump line to tank and creating pressure for the boom and rotate, etc. functions. This needs to happen in order for the machine to function beyond the point where the limit switches open, it's a safety measure designed to prevent operation with the boom up and out if you do not fully extend the axles for stability. The two systems, electrical and hydraulic limit switches work together.

Let me know what you find out!
 

lantraxco

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If you get the machine working and still have heat problems, check valve Y, it seems to be a compensator which keeps pressure low until a function is activated, bypassing oil to tank at a much lower pressure than the relief valve would.
 

usedequipment

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Broken wire found

Dear Lantraxco,
We followed your instructions and found out that wire connect LS2 with CR20 was broken.
After repairing the wire we finally can operate the machine.
However, we faced another problem. We can't extend the boom, we have followed the Troubleshoot from Genie but everything was normal.
Moreover, the Leveling function couldn't auto leveling the platform when we operated the main boom up.
Plus the Steering function worked very poor and it steered very slow.
I hope you could give us some good advices.
Once again, we very appreciate your help !
 

usedequipment

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We have found the problem that disabled boom extend function and got it fixed. There was 1 broken diode connected to valve. After replacing it we now can operate the machine
 

usedequipment

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Dear Lantraxco,
Yes we still have problem with steering function. It works quite slow comparing to other machines. Furthermore, the auto leveling didn't work when we raised the boom. We have check the voltage at the valves and didn't found anything.
I hope you could give some advices !
 

lantraxco

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Is the steering weak also, or just slow to function?

Have you verified main relief valve is set to 2,900 psi?

Valve CC is a priority flow divider, sends 5 gallons per minute oil to the steering manifold, valve YY splits oil off for the chassis jacks and axle extension, maybe you can check somehow. Other possibilities are bad piston seals in the steering cylinders, bad seals in the rotary coupler, malfunction in steering valve VV. Bad O-rings on any valve cartridge in the steering manifold or valve CC in the main manifold could be a problem.

Can you level the basket with the controls, but the auto level does not work when raising and lowering the boom? If so then bad piston seals in the master leveling cylinder underneath the boom at the back end, behind the boom lift cylinder would be my guess.

Almost done!
 

usedequipment

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Dear Lantraxco,
Thanks for your advices,
For the Steering function : It worked but the tires moved slower than others machines. We haven't checked the relief valve yet. We also thought about the O-ring and we are checking that.
For the auto leveling : We can level the basket with control but only when we lower the main boom. When the main boom raised, that function was disabled. Others machines also have the same result. Level function worked when lowered the main boom, when the main boom raised, the basket will auto-leveling.
 

lantraxco

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Okay, so still working on the steering.

For the leveling you are saying that the auto leveling works as the boom goes up and down, and the levelling switches will manually level the basket as long as the boom is down? You mentioned testing, is there no voltage at the steering valve when the boom is up and you operate one of the levelling switches?

I found in the schematic and operation manual reference to:
Machines equipped with Platform Level Control
Disable Function: The platform level toggle switch
will not operate when the boom is raised or
extended past the drive speed limit switches

Perhaps this machine is so equipped?
 

usedequipment

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Dear Lantraxco,
Sorry for my late reply. We have just returned to work after holiday. Up to now, the machine still have problem with steering ( i think we could handle that issue).
However, we had another issue that needed to be fixed : the engine will shut down after 6~8 mins. There was a problem with terminal #9 to relays CR2. If we bypassed that wire (provide 12V to CR2), the engine will continue working. I think the problem has something related to Alternator since we had to remove it once when checking the engine.
The engine also gives us a big headache, it emitted thick black smoke when the machine runs through a rough terrain. I think we have to maintain it as well.
That is the updated information about the machine so far.
We now begin with checking every wires for errors or broken wires. Then we will check the wires to drive valves since the machine was likely moving when we switch to drive mode even though we didn't activate the drive joystick.
Lastly we will check the steering valves and the pressure as you recommended and hopefully the engine as well.
We are so thankful for your kindness when helping us. We hope you have a successful business and happy life !!!
Nick,
 

lantraxco

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For the power to CR2, if i am looking at the correct schematic it looks like you could have a bad ign/start module, bad wire from alternator to terminal #2, or problem with terminal #10 being grounded by a short in the wiring or faulty switch, either oil pressure or coolant temperature. #2 senses alternator pulses as a tachometer input, makes sure engine is turning, #10 is safety for low oil pressure or overheat. Any fault will turn off ignition and fuel pump (if present)

Since it runs for a time before shutting off I would suspect the coolant switch or low oil pressure switch. You might try disconnecting wire from terminal #10 and see if it keeps running, but be sure to watch temperature and put a pressure gauge on the oil, don't want to ruin the engine if oil pressure IS actually low.

Thank you for the kind words, I try to help where I can. Life is short and the world is small yes? Do you ever deal in Morooka dumpers?

Cheers,
Don
 

usedequipment

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Dear Don,
Thanks for your helps. We have tested the oil pressure and heat sensor and they worked normally. When we replaced the ignition/start module with another ones in Genie S80, Tthe symptom disappeared. We are checking the machine under great precaution. Up to now the machine works ok and we are testing it in working environment.
I hope we can finally get it back to work since it costed so much efforts !!!
We rarely see Morooka Dumpers in our place. Maybe, it is used in mining industry.
Regards,
Nick,
 

usedequipment

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Hi Don,
Do you know the pressure inside the function manifold when we start the engine ???
I've checked the service manual specifications. It only mentioned 3 types of pressure relief valves : System (2900psi), boom down(2300psi), boom extend ( 2500psi). When we start the engine, the pressure inside function manifold raised up to 2500psi ( which is extremely high compared with 1000psi in one Genie S80).
I think we have wiring problem to the valve G.
Since i checked the schematic, valve G will receive 12V when we operate any functions. But when we start the engine, it received 12V immediately.
Up to now, the machine work normally for 1~2 hours, then we cannot drive the machine since the hydraulic fluid became excessive hot. I think it somehow related to valve G ( Since it always received 12V when we started the engine, therefore, the pressure built up in the system went high and made the hydraulic fluid very hot).
I think we can fix this problem by checking the wiring system in 1 same Genie S85 unit. We will update information for you.
 

lantraxco

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No, valve G receives power at all times when engine is running and limit switches are closed. Also valve M will be closed any time the axles are fully extended.

Main relief Z is set with function enable switch activated and also boom retract, should be 2,900 psi.

There is a pressure regulating valve, valve Y, if you can swap in one from another machine this may give you a lower pressure reading. Valve Y reads load pressure from any activated function and modulates system pressure to be just high enough to move the load, so oil is not flowing over the relief valve all the time. There may also be an issue of the sense line for valve Y having a high pressure all the time, valve L is a bleed off and may be restricted?
 

usedequipment

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Dear Don,
Did you check the wiring diagram ?? Since we have tested 3 different Genie S80 and Valve G only received power when we lowered the main boom ???
If Valve G receives power all the time, the pressure inside function manifold will be 2,500~2,600 psi. That is very high compared with other Genie S80/85 since we the pressure is 1000~1200psi when we started the engine.

Once more thing, we have another problem with the engine, when we operated the engine for 3~4hrs and switch off. We couldn't start the engine afterwards and we had to wait for 30mins. Then we could start the engine and continued working. We have checked everything but we couldn't find any faults.
The weird part was if we just worked continuously without switching off the engine, it still worked normally. But, by doing that, the engine will wear off very fast and will be broken.
We assumed that the engine became so hot than the system automatically stopped. If so, do we have any tricks to fix this problem and let the engine starts( remove the heat sending unit, or pressure sending unit) ???
Regards,
 

lantraxco

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Yes, and if I am looking at the correct diagram, as long as both the boom up and extend limit switches are closed, you will always have power to valve G. Also, valve M is closed any time the axles are fully extended. If you are getting about 1,000 psi on other machines in standby then as I suggested before you probably have a problem with valve Y or the bleed valve L which works with valve Y, valve Y lowers the standby pressure and only raises it enough to move the load when a function is activated. When the axles are not extended, if you extend the boom far enough to open the limit switch, LS1, that should remove power to valve G I think which will help, but I am fairly sure you need to address valve Y and it's associated circuitry to lower the standby pressure.

Which engine does this machine have, and what fuel? When you attempt to start it while hot, does it spin at a normal speed but just fails to start, or does it struggle to turn over?
 
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