It's not a tractor but it seems to be the same principle. I have a manlift that is a Wisconsin engine and a John Deere pump. Direct drive ? Hooked up by two sprockets and a chain. Problem I am having is engine won't turn over immediately after I shut it down. I have to wait about 10 minutes then I canturn over the motor. Almost like the hydraulic system is bogging down the engine. Any ideas? I started disassembling the pump thinking the pump was shot. The pump would not turn until I drained the fluid. I hooked it all back up and refilled and it started right up and got up to pressure. I am stumped plus I am no expert on hydraulics
Hydraulic issues...help me
- Thread starter Jcorso56
- Start date
Hydraulic circuits on aerial work platforms are designed so as to dump oil directly back to tank unless a function is actuated.
When a function is actuated at least two things need to occur for the function to operate. Let's say you want the platform to lift, so you actuate the lift switch or joystick. That switch or joystick sends an electrical signal to at least two solenoid valves.
The first solenoid valve is a "dump" valve that closes off the pump flow back to tank so the system can build pressure to actuate the desired function. The second solenoid valve is for the function you wish to activate...."lift up" for example. So the first solenoid valve allows the system to build pressure, and the second valve sends that pressure where it needs to go.
If your machine is turning over hard with the starter due to hydraulic pressure in the system, then someone without a schematic has been mucking around with the wiring, or.....the dump valve itself is sticking and not allowing oil to go back to tank when a function isn't selected.
What model machine is this?
When a function is actuated at least two things need to occur for the function to operate. Let's say you want the platform to lift, so you actuate the lift switch or joystick. That switch or joystick sends an electrical signal to at least two solenoid valves.
The first solenoid valve is a "dump" valve that closes off the pump flow back to tank so the system can build pressure to actuate the desired function. The second solenoid valve is for the function you wish to activate...."lift up" for example. So the first solenoid valve allows the system to build pressure, and the second valve sends that pressure where it needs to go.
If your machine is turning over hard with the starter due to hydraulic pressure in the system, then someone without a schematic has been mucking around with the wiring, or.....the dump valve itself is sticking and not allowing oil to go back to tank when a function isn't selected.
What model machine is this?
It is an old grove manlift mz50. I can't find any info from anywhere in regards
to schematics or diagrams. It's funny because if I wait 10 minutes it will start right up. I'm wondering where the dump valve is? The machine is quite old and I bought it used to paint my house. All else fails I will have to keep it running while I am working. It's a pain in the *** and the old lady is all over me...
Any ideas? Thanks for your help in advance bro
to schematics or diagrams. It's funny because if I wait 10 minutes it will start right up. I'm wondering where the dump valve is? The machine is quite old and I bought it used to paint my house. All else fails I will have to keep it running while I am working. It's a pain in the *** and the old lady is all over me...
Any ideas? Thanks for your help in advance bro
I work at a place that's a dealership for several brands, but Grove isn't one of them. Grove got out of the work platform biz a few years ago, and when they did a place called Parts For lifts took over the parts and support business. Parts For Lifts has since joined forces with MinnPar. I've gotten Grove schematics from them a couple of times when working on customers' equipment.
Here's a link:
Fiat Allis Part, Fiat Allis Chalmers Part, Manlift Part, Manlift AWP Part, Northwest Engineering Part, Northwest Crane Part, Bucyrus Crane Part, Trojan O&K Part, Bantam Lorain Part, Barber Greene Part, Dana Clark Hurth Part, Michigan Clark Part, Lull
If they won't provide you directly with the info you need, post back up here with your model and serial number and I'll talk to them.
That's because with the engine off and the pump not turning, there's enough leakage internally in the system for the built-up pressure to bleed off.
If you want, you can check to see which solenoids are powered up with the machine idling, and then unhook them to see if the condition changes. You can check for voltage at the wires, or you can hold something metal against the center of the valves and see which ones are magnetized.
They should look something like this: (this one is actually for a pneumatic system instead of a hydraulic system, but they look very similar)
Place something like a screwdriver or wrench next to the center "stud" where the coil nut is and check for magnetism. If there's magnetism there, that valve is energized. Disconnect them one at a time and see if anything changes.
If nothing changes with the coils de-energized, then the spool inside the cartridge itself is likely stuck.
Here's a link:
Fiat Allis Part, Fiat Allis Chalmers Part, Manlift Part, Manlift AWP Part, Northwest Engineering Part, Northwest Crane Part, Bucyrus Crane Part, Trojan O&K Part, Bantam Lorain Part, Barber Greene Part, Dana Clark Hurth Part, Michigan Clark Part, Lull
If they won't provide you directly with the info you need, post back up here with your model and serial number and I'll talk to them.
That's because with the engine off and the pump not turning, there's enough leakage internally in the system for the built-up pressure to bleed off.
If you want, you can check to see which solenoids are powered up with the machine idling, and then unhook them to see if the condition changes. You can check for voltage at the wires, or you can hold something metal against the center of the valves and see which ones are magnetized.
They should look something like this: (this one is actually for a pneumatic system instead of a hydraulic system, but they look very similar)
Place something like a screwdriver or wrench next to the center "stud" where the coil nut is and check for magnetism. If there's magnetism there, that valve is energized. Disconnect them one at a time and see if anything changes.
If nothing changes with the coils de-energized, then the spool inside the cartridge itself is likely stuck.
Soundguy
Old Timer
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YOu guys were a big help. It was the stupidest thing.
I sat there staring at the hydraulic system for a good 20 minutes tracing where all the lines go....
Then I found what had to be the dump valve and low and behold the power to the pump was disconnected. I am not sure how that happened but somehow the wire was unplugged.... maybe goonies???
So I took apart most of the hydraulic system, changed the battery, starter and all the required wires for the engine, leaked about 2 gallong of fluid all over my driveway and wept for a good hour and all it was was a stupid unplugged wire.... figures
Thanks for all of your help you were wonderful...
One last question. How do I check the fluid levels in teh system without any gauge to be found? I know it has to be low since when it gets at the farthest throw of the pumps it runs out of power.
Thanks
I sat there staring at the hydraulic system for a good 20 minutes tracing where all the lines go....
Then I found what had to be the dump valve and low and behold the power to the pump was disconnected. I am not sure how that happened but somehow the wire was unplugged.... maybe goonies???
So I took apart most of the hydraulic system, changed the battery, starter and all the required wires for the engine, leaked about 2 gallong of fluid all over my driveway and wept for a good hour and all it was was a stupid unplugged wire.... figures
Thanks for all of your help you were wonderful...
One last question. How do I check the fluid levels in teh system without any gauge to be found? I know it has to be low since when it gets at the farthest throw of the pumps it runs out of power.
Thanks
oldnslo
Super Member
Not familiar with that lift but to check oil level pn most lifts all of thecylinders should be fully retracted. Then remove the reservoir cap and fill tow with-in 2- 3 inches of the top. Don't fill it plumb full or when the oil gets warm it will overflow.
There is usually some sort of sight gauge on the reservoir. It may be just a round (window) in a fitting.
Good luck.
Roy
There is usually some sort of sight gauge on the reservoir. It may be just a round (window) in a fitting.
Good luck.
Roy
Soundguy
Old Timer
- Joined
- Mar 11, 2002
- Messages
- 52,238
- Location
- Central florida
- Tractor
- RK 55HC,ym1700, NH7610S, Ford 8N, 2N, NAA, 660, 850 x2, 541, 950, 941D, 951, 2000, 3000, 4000, 4600, 5000, 740, IH 'C' 'H', CUB, John Deere 'B', allis 'G', case VAC
Hopefully your driveway is dirt, or garavel, or concrete... if it is asphalt.. you will be patching it where that 2g of hydraulic fluid hit it...
good luck
soundguy
good luck
soundguy