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 | beaner1
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2002-07-08 40173
I have a 750 w/ a jd 7back hoe which has never been off the tractor. I bought a backblade and tried to use the rock shaft and it won't work. I disconnected the hydraulic lines to the hoe and then hooked them together like I see on all othr jd's with on backhoe but the rockshaft has no response at all. Someone told me that there should be an internal pipe plug in the upper hydraulic line connection to the rockshaft. Is this the cause of my problem?
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| Big Eddy
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2002-07-12 40309
Simple checks before the real troubleshooting begins.
Is the 3 pt Valve (under the seat on an 855?) closed down preventing the rockshaft from moving>
On my 855 I install a solid bar to keep the rockshaft up when I install the backhoe. I remove it when I install the 3pt arms. Ensure it's not installed
Some machines have a latch to keep a mower deck up. Ensure no latch, or not latched.
If this fixes it - great - if not, others can contribute.
Big_Eddy ....
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| beaner 1
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2002-07-14 40367
The valve is open but hydraulics only will work when tractor is revved to 2000 rpm and then they won't even lift 150 lbs. ....
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| Big Eddy
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2002-08-09 41112
If you get some hydraulic action, but only at high revs, and only limited lift (does it leak down after?) it sound to me like you have a seal problem in the cylinder, but I would approach it in a structured fashion.
First check.
Is the relief valve operating? Yes -
Possibilities -
a) seized or blocked mechanical motion. (Can you lift the 3 pt arms manually and do they drop back down?)
b) blockage in the system that prevents flow
c) defective relief valve opening at low pressure (measure the pressure and you will know which of the latter 2)
No
a) either the flow is passing by (seals)
b) not plumbed correctly (but then I wouldn't expect any motion at all)
I assume you have unplugged and reconnected the hoses, and have retried the backhoe to ensure it still works.
I'd try that and see what happens. Check the underseat valve again! Unscrew it all the way and test it at both extremes to make sure it is working.
Big_Eddy ....
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