Model 784 hydraulic rockshaft stuck in full up position

Mich John

Member
Was using my auger boom to lift logs and "dead-headed" the pump with an excessive load (chain held boom in fixed position). I shut down the tractor, freed up the "locked boom position" after which the rockshaft went to full up (what manual refers to as "transport position"). The "position control lever" does NOT respond to any input.

What am I missing here with respect to getting normal function back on the operation of the position control lever or is there a repair required? Hydraulics work otherwise (steering & loader).

As usual, comments appreciated from users (e.g. JimB and the like) are much appreciated.
 
Hi John, from archives from Bernard le m?cano Qu?bec Canada,

3 pt will not go down:

There is a cover on the right side, in front of the rock-shaft. Remove and check if the spool valve moves with the position
lever. Make sure the draft lever is down. There is a long spring, with a rod, maybe the spring is unhooked.


Maybe the unload valve is stuck. Check with engine running, raise the hitch and pull at the same time the remote lever. If the
hitch raises, you have dirt in the unload valve. This valve is under the seat and you remove the large plug for access. One
trick, loosen the large plug, and the unload valve, 2 turns and start the engine, the hitch should raise if the valve is stuck.
It has a small hole in the valve and just blow the dirt out with air. Replace the O rings.


Hope this helps
Jim
 
(quoted from post at 14:26:17 12/07/17) Hi John, from archives from Bernard le m?cano Qu?bec Canada,

3 pt will not go down:

There is a cover on the right side, in front of the rock-shaft. Remove and check if the spool valve moves with the position
lever. Make sure the draft lever is down. There is a long spring, with a rod, maybe the spring is unhooked.


Maybe the unload valve is stuck. Check with engine running, raise the hitch and pull at the same time the remote lever. If the
hitch raises, you have dirt in the unload valve. This valve is under the seat and you remove the large plug for access. One
trick, loosen the large plug, and the unload valve, 2 turns and start the engine, the hitch should raise if the valve is stuck.
It has a small hole in the valve and just blow the dirt out with air. Replace the O rings.


Hope this helps
Jim

Jim - haven't got to the valve yet as "under seat" requires some work to access. Was wondering what would be the harm if I put a load on the drawbar to force the rockshaft down (free up the unload valve) - would this cause ANY potential issues?
Later, Mich John
 

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