Deere 655 SCV won't move

[Davidritenburgh]

I have a Deere 655 with a factory SCV for a loader. I put a newer 200cx loader on it. It worked well at first, but over time it has developed and issue where when lowering the loader quickly something hydraulically locks up and the loader won't go down. If I lift the loader just a little bit and lower it very slowly then the loader will lower ok. The same issue exists with the bucket cylinders. The bucket moves well one way, but it locks up when moving the other way and the only way to release it is to reverse direction and go back slowly. I cannot figure out what could cause this, It acts like some sort of check valve seats when the flow is significant and it must be unseated by reversing fluid flow direction to correct it. Any ideas? BTW, the same condition exists when I hook up the front mount snow blower.

 

[Tx Jim]

:welcome: to TBN
I agree it sounds as if a check valve is blocking return oil path to sump.

 

[J_J]

Check your QD's as the pressure might try and close the ball and spring preventing fluid from moving.

If you move it slow, less pressure might not move the spring and ball and let fluid pass.

You might have to replace QD's or go to a straight coupler, with no QD's.

 

[Davidritenburgh]

Check your QD's as the pressure might try and close the ball and spring preventing fluid from moving.

If you move it slow, less pressure might not move the spring and ball and let fluid pass.

You might have to replace QD's or go to a straight coupler, with no QD's.

I believe you are exactly right. Late last night I put the loader up and quickly let it down to lock it. I then started cracking lines from the scvs back to the cylinders and I found that I can crack the line right at the scv side of the QD and the loader still stays up. I believe I have the round type QD and Deere used the pointed type.