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Discussion Starter #1 (Edited)
I’ve had this problem for a while now with my JD 1026R. In fact, pretty much since I purchased the tractor in 2011. I honestly haven’t used the mower more than a hand full of times since I bought my rig. The problem is, after dropping the mower and raising the mid PTO to get it out of the way, it doesn’t lower again. It was going up and down fine with the mower deck attached, but since I last dropped the mower and raised the mid PTO, the mid PTO will not lower using the SCV.

My rig is out of warranty, so I decided to troubleshoot and attempt a repair myself. Not knowing too much about the mechanics of the system, I tried to find as much information as I could online, and in the operating manual. I’m confident that I’m operating the system properly, and verified that the mower height control knob is in the “install” position. I crawled under the tractor to verify that the cam is not preventing the trapeze from lowering. Someone suggested checking the drop/lock rate valve knob to make sure it wasn’t in the min position, but from everything I’ve read this valve has nothing to do with the mid PTO with the auto connect system. The system is controlled by the SCV.

I had to remove the deck on the tractor in order to get a good look at the auto connect system. This is a little bit of a procedure that I’ll share with anyone interested. Most of the auto connect system is mechanical, with the exception of one hydraulically actuated piston – part number LVA15396. This is more of an accumulator than a piston in that it only has one hydraulic fitting. It appears to me that hydraulic fluid is forced into the LVA15396 to raise the trapeze, and when pressure is released, it should allow the trapeze to lower due to the weight of the trapeze along with a spring assist. Even without the mower deck installed, there is a good amount of weight there to force the LVA 15396 to retract allowing the trapeze to lower into the install position.

I ordered a new LVA15396, because I believe that there is a problem inside this accumulator. I’m hoping that replacing it will solve the problem. I’ll post again to let others know in case they’re having a similar problem.
 

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I was having the same problem a few weeks ago. In the hose , on the cylinder side, there is a small round restrictor disc, called an orifice. On mine, a small particle had gotten in and clogged it, reducing the flow even further. A small piece of piano wire was able to clear the blockage and return the functionality of the mechanism. May want to give that a look first.
 

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Discussion Starter #3
The LVA15396

I was having the same problem a few weeks ago. In the hose , on the cylinder side, there is a small round restrictor disc, called an orifice. On mine, a small particle had gotten in and clogged it, reducing the flow even further. A small piece of piano wire was able to clear the blockage and return the functionality of the mechanism. May want to give that a look first.
Thanks "lewisc1985," I'll give that a look!

Cheers,

John
 

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Discussion Starter #4 (Edited)
Lost and found

Thanks "lewisc1985," I'll give that a look!

Cheers,

John
WOW - thanks again for posting Lewis. The restrictor you mentioned fell out of the fitting when I removed it, and I didn't notice. I just went out and found it laying on the ground where I first removed the hydraulic hose. The little hole does appear to be blocked. I'll clean it out and reinstall. I should have posted first and got your advice before I took everything apart. Oh well - lesson learned. I'm learning more about my tractor though.

Quick question - which way does the orifice go in. Does the rubber gasket go towards the fitting on the LVA15396?

Thanks again,

John
 

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WOW - thanks again for posting Lewis. The restrictor you mentioned fell out of the fitting when I removed it, and I didn't notice. I just went out and found it laying on the ground where I first removed the hydraulic hose. The little hole does appear to be blocked. I'll clean it out and reinstall. I should have posted first and got your advice before I took everything apart. Oh well - lesson learned. I'm learning more about my tractor though.

Quick question - which way does the orifice go in. Does the rubber gasket go towards the fitting on the LVA15396?

Thanks again,

John
The orifice gets turned so that the O-ring on the orifice contacts the flat face inside the swivel nut on the hose. The smooth face of the orifice contacts the o-ring on the adapter threaded into the lift cylinder.
The item that you referred to above as an accumulator is actually the mmm lift cylinder. This is a single acting cylinder. Oil feeds to it when lifting the mmm. When lowering, the oil is pushed out of the cylinder, back through the SCV and back to tank/diff. simply by the weight of the mmm linkage and the return assist spring. This returning of oil takes time and with just the linkage pulling it down, you have to be patient.
When I lower my mmm linkage, I always push the SCV to the right slightly (do not push the SCV too far to the right). Hold the SCV in this position for about 10 seconds, then look under the tractor to see if the linkage has dropped. It is has, I put my foot on the left side of the linkage, reach across and push the SCV to the right again while applying some pressure with my foot. This assures the linkage is all the way down. Then I drive over the mmm.
 

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Discussion Starter #6
Thank you

The orifice gets turned so that the O-ring on the orifice contacts the flat face inside the swivel nut on the hose. The smooth face of the orifice contacts the o-ring on the adapter threaded into the lift cylinder.
The item that you referred to above as an accumulator is actually the mmm lift cylinder. This is a single acting cylinder. Oil feeds to it when lifting the mmm. When lowering, the oil is pushed out of the cylinder, back through the SCV and back to tank/diff. simply by the weight of the mmm linkage and the return assist spring. This returning of oil takes time and with just the linkage pulling it down, you have to be patient.
When I lower my mmm linkage, I always push the SCV to the right slightly (do not push the SCV too far to the right). Hold the SCV in this position for about 10 seconds, then look under the tractor to see if the linkage has dropped. It is has, I put my foot on the left side of the linkage, reach across and push the SCV to the right again while applying some pressure with my foot. This assures the linkage is all the way down. Then I drive over the mmm.
Thank you Ray for the detailed explanation. Now I understand the system better and will install the orifice correctly.

Cheers,

John
 

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Thank you Ray for the detailed explanation. Now I understand the system better and will install the orifice correctly.

Cheers,

John
:thumbup1gif:
 

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Discussion Starter #8
Just an update_2 July 2017

I tried just cleaning out the orifice, and reinstalling, but it didn't solve my problem. The mechanism retracted OK, but it wouldn't lower without pushing on one of the mechanical linkages. This is easy to access with the flooring removed, but it wouldn't be with everything put back together. I ended up replacing the LVA15396, and now it works the way it was intended to. It's an expensive part, but I'm glad to have the system functioning properly. LVA15396.jpg
 
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