How can I test a loader for cylinder vs control valve leakage??

   / How can I test a loader for cylinder vs control valve leakage??
  • Thread Starter
#31  
I'm about to do a test this weekend and was thinking about this some more. Here is my test to isolate the issue from a cylinder seal vs spool leak (remember, there is NO external leaking of oil in my system):

1. If I raise the loader, put a block under it, remove the hose on BOTH the extension and retraction side of the cylinder so the test is isolated to the cylinder and not the valve, and remove the block under the loader...

a) If loader drops then there is a cylinder seal leak in one or both cylinders
b) If loader stays then there no cylinder seal leak


Now lets say the loader stays in the above scenario confirming that the there is NO cylinder leak. Then I can confirm the spool valve leak by...


2. If I swap the hoses to the extension/retraction loader cylinders, then raise the loader by moving the joystick in the down position until the front wheels are off the ground...

a) If the loader does not drop and tractor does not sink back to the ground, then there is a leak in expansion spool


What do you think?
 
   / How can I test a loader for cylinder vs control valve leakage?? #32  
4lane
Your test #1 will prove nothing since you could remove the piston seals and the loader will not drop with both hoses plugged. For the cylinders to drift you must provide a path for oil to escape the rod end of the cylinder.

There is no question that the valve is leaking the question is from which end of the cylinder is the oil escaping through the valve. That is what I have been trying to help you determine by leaving the rod end hose connected to the valve and with the cap end quick disconnect unplugged

I know multiple people say this is to difficult or won稚 work all I ask is prove me wrong.
 
   / How can I test a loader for cylinder vs control valve leakage?? #33  
If you want to go through the difficulties of re connecting the hoses under pressure for fun then go for it. If you don’t believe us than go for it. THE CYLINDER CAN NOT RETRACT WITHOUT SPILLING OIL. That can happen through the valve or out the plumbing or out the end of the cylinder. If you want to test the cylinder seals unplug the quick connect on the barrel end and take the hose off the rod end. Any oil that leaks past will come out the open hose.
 
   / How can I test a loader for cylinder vs control valve leakage??
  • Thread Starter
#34  
oldnslo said:
4lane
Your test #1 will prove nothing since you could remove the piston seals and the loader will not drop with both hoses plugged. For the cylinders to drift you must provide a path for oil to escape the rod end of the cylinder.
Click to expand...

If you extend the cylinder all the way, and disconnect the hoses so oil is contained in the cylinder, the oil does have a path to escape the rod end of the cylinder - by leaking through the piston seals to the other side of the cylinder. No?
 
   / How can I test a loader for cylinder vs control valve leakage?? #35  
4lane said:
If you extend the cylinder all the way, and disconnect the hoses so oil is contained in the cylinder, the oil does have a path to escape the rod end of the cylinder - by leaking through the piston seals to the other side of the cylinder. No?
Click to expand...

No. I used to be of the same belief until a lengthy thread a while back. As the rod moves into the cylinder it takes up more room than you started with. Try sticking a broom handle in a glass of water that’s filled to the brim without spilling any.
 
   / How can I test a loader for cylinder vs control valve leakage?? #36  
4570Man said:
No. I used to be of the same belief until a lengthy thread a while back. As the rod moves into the cylinder it takes up more room than you started with. Try sticking a broom handle in a glass of water that’s filled to the brim without spilling any.
Click to expand...

The Original post had a rather interesting twist.

Bucket curl "sag" is usually in cylinder extension. So the in-compressibility of the fluid and the rod displacement explanation does not apply. The symptom was the initial sudden drop, then a slow lowering. Add to that the boom droop, and you see a combination of leaky cylinder seals AND a leaky control valve. For as the bucket curl cylinders were asking for fluid as the volume increased with droop, the boom cylinders need a place for excess volume to go. Logical!

Now a bit of fluid leaking past a typical control valve won't distract from operations or performance. The time and volumes just are not there. The leak down of elements raises concern. And as this thread shows, Rightfully so!

Think Smart!

;-)
 
   / How can I test a loader for cylinder vs control valve leakage??
  • Thread Starter
#37  
Great, understood. Thanks everyone. How difficult is it to reconnect the hose if I have a jack under the loader and jack it up to release pressure. I壇 love to do oldnslo痴 test assuming I can get the hose reconnected easily enough.
 
   / How can I test a loader for cylinder vs control valve leakage?? #38  
It’s possible for the cylinder to extend out ( read bucket curl down ) without getting more oil in the cylinder. And it’s likely to leak past the valve faster since it’s higher pressure.
 
   / How can I test a loader for cylinder vs control valve leakage?? #39  
4lane
Using a jack you should be able to disconnect & reconnect the quick disconnect. Just have to lift the loader enough to remove the pressure from the disconnect.
 
   / How can I test a loader for cylinder vs control valve leakage?? #40  
Just disconnect it about 8” from the ground and use the bucket curl to lift it back up. You’ll probably still have to loosen a fitting on the cylinder to bleed pressure.
 
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