OT?-Hydraulic Winch Not Lifting Load

[idacal]

I had a valve bank that got some moisture in it and it cracked one spool internally sitting over winter, that was a fun one to figure out. if it was me I would start by checking pressure and gpm at both pumps its just fittings, time, oil, a needle valve, and a measuring jug. after that start from the winch and follow all the lines and see if there is a valve in the system that's gummed up. if you have access to other hydraulic power units break the lines for the winch off the valve and run it with a known working system. on old equipment it is usually the pump but this last go-a-round for me it was the winch. but you don't have pressure to the winch so it has to be pump or valves a couple of test hoses will allow you enough room to change to a known good spool. valves and pressure relieve units when bad seem to make odd noises, and vibrations pumps do not. JMO

 

[m16ty]

There is still a possibility there is something wrong with your winch motor. I can’t tell if you have the gauge in a tee, or hooked directly to the port. If it’s in a tee, and something is broken in the motor, allowing oil to pass though without resistance, you will get a zero or low pressure on a teed gauge tap.

 

[muckalee]

The relief valve may be in the valve spool piece itself. Pull the spool and check for broken springs, missing parts, etc. Installing the relief valve in the spool keeps operators and maintenance from raising the lifting capacity and breaking the winch rope, tipping the vehicle, etc.
The spool can be removed with the valve in place. Remove cap on bottom of valve, unscrew the retaining cap screw, capture the washer cap screw, washers and spring. remove actuator handle and push up on the spool to remove.
If the lower cap contains much oil. now is a good time to replace both o rings. When the lower o rings leak, the cap can fill with oil and prevent the spool from operating in both of spool's functions.
A quick check, if the cap contains oil, clean out cap and install and check lift function before proceeding to removing spool.

 

[e-fishin-c]

If you didn’t already check this, I’d pull that relief valve out and check a very tiny hole in that relief piston, common for the hole to be plugged and the relief valve would be inoperable.
If the control spool is not stroking (loose bolt or spring jammed etc) then that could be something to look at.
Or if one of the cartridge sections of that dual Vickers vane pump is connected to that valve section it will explain why some of the hydraulics are working. You would need a flow/load meter to check flow and load pressure.

 

[garyhlucas]

You may have a pilot operated relief valve on the winch. There certainly is one on the boom lift cylinder. It requires pressure in the circuit before the valve will open so you can't drop a load with no pressure to hold it up.

Had one of these polecats and the power steering on the 4x6 truck wasn't working because of a burst hose. Was fun driving it 25 miles down the mountain roads from Johnstown PA with no power steering! Got to the dealer and got the hose and asked about a manual for the whole truck. He said no one buys those they are $400! I told him to add it to the bill, and it was worth every cent for stuff like you are going through.

 

[alskdjfhg]

I made up some adapter fittings to adapt the 3/4 JIC hose to fit onto a 3/8 JIC valve.

The valve I plumbed into is run off the other pump section. Now the winch works.

I can pick up a load with the winch and the pressure gauge goes to 2000/2500 PSI.

Im probably going to leave it like this for a while. Next most pressing thing is the leaking out rigger cylinders.

Im thinking I have a bad pump section or something is porting to tank inside the valve block on the original winch valve.

I may also have something leaking in the rotary, but I think that's the least likely at this point

Also learned that a 3000 lb tractor rear end at 20' radius will make the front of this truck start to come off the ground....

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[gbent]

Picking over the back is one thing. Swinging over the side is a whole 'nuther animal.

 

[alskdjfhg]

The real problem is that the piston seals on the main out riggers (the back two) leak so bad they are acting like shock absorbers instead of cylinders and allow fluid to flow past the piston.

So under load they are retracting.

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[svs]

It sure is fun having worn out broken down stuff....Always something to do before you can do the thing that needs done.


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[alskdjfhg]

It sure is fun having worn out broken down stuff....Always something to do before you can do the thing that needs done.


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One of the reasons I'm looking at some newer equipment

Getting tired of having to be a mechinc for 3 weeks to use something for an hour

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[john.k]

Thats what I like about my old Harman crawler crane....nothing but asbestos lined bands ,all mechanical linkages ,only oil is in the engine .....it sat for 14 years most recently,then I put the radiator and starter back in ,and the old girl did several months work scrapping amd moving collectables (junk).....the Gardner diesel runs on a mix of waste compressor oil and just enough diesel to thin the mix....Fuel thieves are taking waste oil.

 

[DDoug]

Fuel thieves are taking waste oil.

Man-O-Man is it getting bad down there....

 

[Strostkovy]

I only skimmed this thread but assuming a fixed displacement pump you can cap the lines to the winch motor, and try operating the winch valves. If the motor is broken the pump will load up hard and you'll hear the engine bog down and the relief valve bypassing. If that doesn't happen then it is a pump or valve issue.

If you choose to cap other lines be sure that it is after a functioning relief valve.

 

[Garwood]

If you choose to cap other lines be sure that it is after a functioning relief valve.

Well, If the relief isn't working you'll find out real fast.

 

[john.k]

The winch may have clutch plates inside the drum so it can free spool,and it may have a brake thats dragging.............and definitely repair the outriggers.....if one gives way under load,there is a good chance of bending the truck chassis...............my Atlas crane came from a friends estste............an outrigger seal blew,and when I pulled it down he had made a seal from rope ,teflon pipe tape and silastic..........fortunately it was the one in the end of the ram ,not the load sustaining seal.

 

[Strostkovy]

Well, If the relief isn't working you'll find out real fast.

You'll find a stuck relief valve real fast regardless. Unless you are super careful to never max out travel on any cylinder.