Loader Problem

   / Loader Problem #1  

HammockLand

New member
Joined
Dec 12, 2004
Messages
15
Location
East Florida
Tractor
DK 65, 1948 Farmall Cub. YM1700.
I now have 32 hours on the new DK65 and have been moving fill dirt from the back pasture to fill the stump holes where the trees damaged or blown over by the hurricanes were in the front and back yards. The tractor has performed flawlessly, but I can't say the same for the loader system.

It seems that when the fluid gets warm the curl and roll functions of the bucket start acting strange and there is a sound of fluid flowing through a small opening coming from the area of the control spool valves. The loader has plenty of breakout power and the curl is strong. However, when dumping the roll seems slow and actually stops about 15 degrees from completion. If I hold the joy stick in roll mode it will restart and complete the full motion in about 8-10 seconds. If I go through this process then the bucket seems to work normally until I curl it again.

However, if I let it be where it stops rolling and lower it to the ground and go into reverse (for troubleshooting purposes) it will flop back to level with no resistance. This happens whether I lower it in powered or float mode. Also, if while in the above level position I attempt to curl the bucket there is a long pause before it moves toward fully curled.

Has anyone experienced such a problem? Do any of you technicians have a theory or explanation of the cause of the problem?
 
   / Loader Problem #2  
It sounds like you are experiencing "cavitation" in the system. When dumping, the weight of the load is driving the bucket down faster than the pump can replenish the oil in the cylinders so air is sucked into the system through the venting port. In addition this can happen when back dragging with the bucket tilted downward. Cavitation can happen on most loaders so I don't think it is a problem with just yours. When it occurs you need to "burp" the system by exercising the full stroke of all cylinders with no load on the bucket and high engine speed.

There are a couple of things you can do to try to prevent cavitation:

(1) Keep your engine speed up when dumping or back dragging so the pump is producing as much flow as it can.

(2) When you dump the bucket, push the joystick completely into the detent mode so that the regenerative portion of the circuit is effective. This causes the bucket to dump fast. The regen circuit is used in loaders to help the bucket dump as fast as possible. If you choose to "feather" the joystick for a slower more controlled dump, be sure the engine speed is high.

JackIL
 
   / Loader Problem #3  
Sometimes weird things can happen if you bump the remote stick and cause it to dead-head into the quick disconnect. Just a quick easy one to check before going deeper.
KO
 
   / Loader Problem #4  
I agree with Kiohio, check the quick disconnects first to ensure that they are completly sealed. The only times I've had a problem similar to yours is when a QD is not connected well. Usually though, it comes apart after a few initiations of bucket action if not connected well.

Air in the system is a viable concern as well, follow JackIL's advice in that respect.

Just for kicks, is your loader hooked up to the proper outlets? Forward = D/U, Right = dump etc.? John
 
   / Loader Problem #5  
Hammockland, When you lower the bucket down from the up position do you put in the float position?
Try to limit the the use of the float position.
 
   / Loader Problem
  • Thread Starter
#6  
Thanks for the quick replies. Taken in order;

JackIL, I was not operating the engine at a very high speed, so I reved it up to 2250 rpm and ran through all the actions. It worked much better, but it still pauses for an instant at the same point that it had stopped before. As for a detent in the dump position of the joy stick, mine doesn’t seem to have one so I don’t know about a regenerative circuit. Maybe someone can confirm if a DK65 has one.

Kiohio, I have checked the rear auxiliary control levers many times to be sure they are not in the activated position. In fact, I’m paranoid about that.

John, the connects are in the right place. I have checked them for leaks and they seem to be dry.

Wallace, the only time I use float is when the bucket is on the ground to spread/level dirt. I don’t lower the boom in float, ever.

Although the loader operation still doesn’t feel right, I will keep using higher rpm and practicing while I observe and make notes. Thanks again for all the good suggestions.
 
   / Loader Problem #7  
Like Jack said, It is captivation. The cylinders are getting air separated from the fluid. If you don't have a regenerative position on your valve, keep the rpms up when dumping a heavy bucket
 
   / Loader Problem #8  
<font color="blue"> As for a detent in the dump position of the joy stick, mine doesn’t seem to have one so I don’t know about a regenerative circuit.</font>

You'll need to have a heavy load in the bucket to visually detect the faster movement of the bucket as it dumps. It basically releases the bucket and let's gravity take its course. When the bucket is empty it is diffucult to detect.

Don
 
   / Loader Problem #9  
Hammockland,

Is the level of your hydraulic fluid right up where its supposed to be? "My" reason for asking this is that from my understanding is that the loader is probably almost fully up (cylinders fully loaded with oil) and the dumping position (cylinders almost fully extended) is almost reached. Either because its possible to suck air out of the tank in the float position or the pump maybe sucking air due to a low level in combination with the tractor bouncing around. Maybe a stupid theory but something to check if you haven't found a solution yet.

Steve
 
   / Loader Problem
  • Thread Starter
#10  
Thanks Jerry, Don and Steve for your input.

Yes my fluid is right at the mark. My understanding of how the loader circuits work is as follows.

Each cylinder for the loader arms and for the bucket has two sections. A front and a back cavity with the piston in the middle. The control valve allows fluid under pressure into the appropriate end to cause the desired action and opens the passageway for the opposite end so the fluid can escape that end of the cylinder into the sump. I am assuming that the escape port is below fluid level within the sump. Ignoring float for the moment, it seems to me if the sump and the pump input has adequate fluid level there is no way for air to get into a cylinder.

In float mode it seems to me that the passageway for each end of the cylinder is opened to allow fluid in the sump to flow into and out of each end of the cylinder as dictated by the up and down movement of the arms following the contour of the ground. Again, if the sump is full no air should get into the lines.

Someone correct me if I am wrong. Thanks.
 
 
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