Used/rebuilt Kioti loader control valve options

[TX mower]

.... I have to say, after that discussion I'm still perplexed as to how I'd know the cylinder seals are faulty. ...

Perhaps of interest:

TESTING A DOUBLE ACTING HYDRAULIC CYLINDER (pdf file)

Describing a series of diagnostic tests that can be done with cylinders installed / in-situ (from this page on K&E Technical, Inc. website)

 

[4lane]

Agreed that this is a good first step. As others have noted in the past, there is a loopholes to oldnslo's test. Namely that the valve has to have some leaking (at least per spec) in order to make any determination on whether the cylinders seals are leaking or not. That is an assumption we're making here. So.. only one of two things is going to happen when you remove the jack from under the loader; it will drop or it won't.

1) If loader doesn't drop, then...
a) valve doesn't leak, cylinders don't leak
b) valve doesn't leak, cylinders do leak

2) If loader does drop, then...
c) valve leaks, cylinders leak


If #1 happens, great, I will have eliminated the valve as the issue. But, we're going on the assumption that the valve leaks a little (at least per spec) so #2 is the scenario we're looking for.

Keep me honest here, this is what I'm thinking...

 

[oldnslo]

Your thinking is correct 4lane

My money is on option 2

 

[LouNY]

One simple way to check for cylinder piston seal leaks is to retract the cylinder(s) all the way, remove the hose(s) from the base of the cylinder(s) and try to retract it/them more if oil flows out the cylinder port under pressure the piston seal is leaking.
If you wish to know how much put a hose on it to a container, maintain pressure for 10 seconds measure the fluid volume displaced multiply by 6 that is the flow rate of the leak at that pressure per minute.

 

[4lane]

This weekend I did OldnSlo's test. The loader did drop, about 1in/30sec - the same drop rate as when using the loader normally. So, my conclusion is:

• The piston seals WERE leaking, because the oil had a path to return to the tank since the rod end hose was connected
• If the piston seals were not leaking and the control valve was leaking, the loader would not have dropped in this test since the cap end hose was disconnected/blocked off.

Is that correct? I've proven that the piston seals are leaking regardless of if the control valve is leaking or not?

 

[K5lwq]

4lane,

You are correct. If you fix the cylinders, you might be satisfied with the internal valve leakage.

 

[oldnslo]

This weekend I did OldnSlo's test. The loader did drop, about 1in/30sec - the same drop rate as when using the loader normally. So, my conclusion is:

• The piston seals WERE leaking, because the oil had a path to return to the tank since the rod end hose was connected
• If the piston seals were not leaking and the control valve was leaking, the loader would not have dropped in this test since the cap end hose was disconnected/blocked off.

Is that correct? I've proven that the piston seals are leaking regardless of if the control valve is leaking or not?

4lane
I greatly appreciate you posting your test results.

You have proven that the piston seals and rod end port of the valve leaks. If the valve did not leak the cylinder would not drift.

This proves that the leak path through the rod end valve port is definitely contributing to the loader drift.

 

[4lane]

4lane
I greatly appreciate you posting your test results.

You have proven that the piston seals and rod end port of the valve leaks. If the valve did not leak the cylinder would not drift.

This proves that the leak path through the rod end valve port is definitely contributing to the loader drift.

Thank you again for all your insights. I'm going to post these results to the June thread on this topic since it was solely focused on this issue.